Sustainable Small-scale Nursery Production

1. Sustainable Small-Scale
ATTRA Nursery Production
A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.org
By Steve Diver and Sustainable nursery practices can increase plant marketability and reduce a nursery’s impact on the
Lane Greer environment. This publication focuses on the sustainable production of woody and herbaceous nursery
Updated June 2008 plants, both in containers and in the field. It is not a primer for inexperienced growers, but a comple-
by Katherine L. Adam mentary source of information that concentrates on sustainable production techniques. Topics covered
Agriculture Specialist include integrated pest management, weed control and alternative fertilizers. The publication also
© 2008 NCAT introduces business management practices.
Contents Introduction
Marketing ......................... 2 This publication is for small-scale nurs-
General ery managers who want to use sustainable
production ....................... 3
practices and large-scale nursery managers
Integrated pest
management .................. 6 interested in converting from conventional
Container to sustainable practices. In this publication,
production ....................... 7 small-scale defines a nursery with fewer
Field than five acres in container production and
production ..................... 14 fewer than 15 acres in field production. This
Costs.................................. 18 publication does not include everything a
Summary ......................... 19 nursery manager needs to know before going
References ..................... 19 into production.
Resources ....................... 21
A nursery can be part of a diversification
strategy to make a farm more profitable
or a nursery can be a sole enterprise. In
either case, it is important to start small and
expand later. For general information on
standard nursery production, please refer to
publications and bulletins published by the
Rows of greenbean beanstalks. Photo by Jandre Venter
Cooperative Extension Service and common
horticultural texts and trade magazines.
See the Resources: Publications section Department of Agriculture National Agri-
at the end of this document for a listing of cultural Statistics Service fi gures show a
nursery literature. slight increase over 2006 in wholesale value
of U.S. floriculture crops, the largest seg-
Sustainable nursery practices aim to reduce ment of the nursery industry (1a). The most
levels of synthetic fertilizers and pesticides, important things to consider before start-
use integrated pest management systems to ing production are what crops to grow and
ATTRA – National Sustainable
Agriculture Information Service is
deal with insects, diseases and weeds and how to market them. In today’s economy, it
managed by the National Center for focus on building the soil to promote plant is no longer possible to grow crops without
Appropriate Technology (NCAT)
and is funded under a grant health. This document discusses sustain- fi rst considering the crop’s marketability.
from the U.S. Department of able nursery production in general before Here are some facts to keep in mind before
Agriculture’s Rural Business-
Cooperative Service. Visit the moving to sustainable container and field starting out:
NCAT Web site (www.ncat.org/ production techniques.
sarc_current.php) for • Container-grown crops generate
more information on
our sustainable agri-
The nursery industry appears to be hold- about 10 times more sales per acre
culture projects. ing its own through 2007. The latest U. S. than field crops (1).

2. • Lawn and garden centers draw • Mass merchandisers want large volumes of a
approximately 80 percent of their few popular plant species. Mass merchan-
customers from a 5- to 15-mile disers purchase smaller plants. These cus-
radius (2). More than 60 percent tomers may not care about buying specific
of an average wholesale nursery’s plants, but focus on obtaining a good mix
sales are to customers from within of fast-moving materials. Demand from
the state. Small nurseries sell about these customers is seasonal (1). Plants in
20 percent of their plants to out-of- fashion vary from year to year.
state customers (1).
• Retail garden centers usually want There are several disadvantages to deal-
Related ATTRA small plants in 1- to 3-gallon con- ing with mass merchandisers. These cus-
Publications tainers. Landscaping firms and tomers want instant shipment, pay the
Solar Greenhouse landscapers want larger container lowest price for plants and often do not
Resources (Web only) plants in 3- to 5-gallon containers take care of plants after receiving them,
and balled and burlapped woody which can reflect poorly on a nursery.
Renewable Energy
Opportunities on plants. • Landscapers look for large, high-quality
the Farm • The nursery industry is dependent specimens carefully identified by cultivar.
Energy Saving Tips on the construction industry and Landscapers generally want to buy plants
for Irrigators on the rate of unemployment in the from a limited number of producers but
vicinity of the nursery (1). also want to choose among many plants
Woody Ornamentals
for Cut Flower and plant sizes. Landscaper purchases
Growers Marketing are spread out through the year, with an
Phenology Web Links: Before entering the nursery business, a mar- emphasis on spring planting (1). Horticul-
Sequence of Bloom, ket analysis is necessary to determine what ture degrees with specialization in land-
Floral Calendars, opportunities exist to sell plant materials in scape architecture were popular career
What’s in Bloom the local area. Most new fi rms begin with choices in the 1980s and 1990s, creating
(Web only) only a few acres of production and market a solid base for nursery customers.
Agricultural Business in a 50-mile radius, unless growing for mail
Planning Templates order or on contract (1). A market analysis • Lawn and garden centers fall somewhere
and Resources includes finding out what crops other nurs- between the mass merchandiser and the
Biointensive
eries grow successfully in the region. The landscaper. Some centers want variety in
Integrated Pest analysis also evaluates competition potential plants and plant sizes, some do not.
Management from area nurserymen. When considering
the market, bear in mind this advice from Other retail outlets include mail order, Web
Nematodes:
Lynn Byczynski, editor of Growing for Mar- sites, farmers’ markets and starting a land-
Alternative Controls
ket, a newsletter for small-scale producers: scaping business. Sales at farmers’ markets
Use of Baking Soda as will be local, but local can mean weekly
“I feel quite strongly that it is a serious mis-
a Fungicide
take to commit to growing for anyone before travel of 200 to 300 miles to a large metro-
Notes on you have become extremely confident of your politan area. Potential customers all share
Compost Teas skill as a grower. My recommendation for a common need to get uniform, well-grown
marketing is a simple one: Start where no plants from a producer without having to
Integrated Pest one is depending on you. If you have nothing
Management for to sell, no one will have to know”(3). inspect the crop before each purchase (1).
Greenhouse Crops
Marketing starts with a decision about what 2) Keep up with trends in buyer preferences.
to produce and at what volume. Nursery Constant monitoring of customer character-
managers need to: istics and purchases is crucial. Advertising
1) Determine what kind of customer the nurs- and promotion never end. Chain stores now
ery will attract and what size of plants those carry nursery items. Convenience and esca-
customers want. lating gas prices promote one-stop shopping.
Page 2 ATTRA Sustainable Small-Scale Nursery Production

3. Table 1. Types of nurseries plants. A concerted effort at the federal
level to limit introductions of plant species
Type Description
to the United States raised concerns on the
Grower/retail Grows and sells plants part of some plant explorers and nursery
nursery on-site owners. However, it encouraged renewed
Wholesale Grows plants for sale to interest in native species formerly put at a
nursery other nurseries, disadvantage by foreign imports, not only for
landscapers or retailers, in situ conservation, but also for increased
may grow plants on a
contract basis
use in landscaping. Several plants on inva-
sive lists throughout the United States are
Landscape Provides landscape important to the nursery trade. Plants such
nursery services and retail sales
as Norway maple, butterfly bush, Japanese
Farmers’ Grows plants to sell locally barberry and miscanthus have been lucra-
market at retail prices tive sellers (4).
Mail order/ Grows plants to sell at the
Web site national level* The USDA now maintains a Web site on
*Note: Recent legislation made it easier for states to invasive flora and fauna species at www.
collect sales tax on Internet sales. invasivespeciesinfo.gov. The National Park
Service provides plant fact sheets and a
helpful list of natural area invaders at www.
3) Know what combination of plants will nps.gov/plants/alien. Consulting such lists is
maximize profits. advisable when making decisions on offer-
ing nursery stock to the public.
Ornamental plants fall into general catego-
ries of shade trees, conifers, perennials,
vines, shrubs, bulbs and annuals. While
most nurseries grow a range of plants, there
is a trend toward specialization. Growing
only native groundcovers or only daylilies
are viable niche markets. The production of
specialty crops, such as hardy bamboo and
disease-free apple stock, and specialization
in plants in short supply, like uncommon
plants and very large trees, are niche mar-
kets even small growers can serve.
Keep abreast of recent developments in
the industry. Subscribing to trade publica-
tions and attending trade shows or confer-
ences are good ways to learn about grower
issues like plant availability, new varieties
for specific needs, popular sizes, specific
growing conditions and enhanced services. General production
Enhanced services can include providing
There are two types of nursery production:
photographs of plants and making presen-
field and container. Field stock is either
tations to landscape architects and other
direct-seeded or transplanted from seed-
potential customers.
lings and then lifted as bare-root stock for
use as nursery liners, fruit trees, seed-
Invasive species lings for Christmas trees, windbreaks and
The USDA and other government agencies conservation plantings. Field stock is also
are increasingly concerned about invasive grown for balled and burlapped landscape
plant imports. Drug enforcement personnel or shade trees. Container stock, which is
are also concerned about the use of some propagated from seed, rooted cuttings and
www.attra.ncat.org ATTRA Page 3

4. Container and field production will be dis-
Grower profile: Santa Ana Garden Center and Santa Ana cussed separately, but there is commonality
Native Plant and Tree Nursery between the two forms of production. Most
The Santa Ana Pueblo, a small suburb of 497 residents, is located two woody landscape plants, regardless of how
miles north of Albuquerque, New Mexico. The town is home to a retail they are grown, are propagated by cuttings.
nursery and a wholesale nursery that supply plants and trees that thrive Both types of production require spending
under arid local conditions. The Pueblo of Santa Ana Tribal Enterprises a high percentage of a nursery’s budgets on
operates the retail Santa Ana Garden Center and the wholesale Santa farm-type mechanized implements and fer-
Ana Native Plant and Tree Nursery.
tilizers (1).
Since tribal water rights to the adjacent Rio Grande take precedence, the
garden center and nursery, along with a tribally operated golf course,
Soil productivity is not as important when
greatly enhance landscaping and recreation options for Albuquerque growing only containerized products, but
and area residents. relatively level land with good drainage is
still necessary. Beginning nursery manag-
The Santa Ana Garden Center and Santa Ana Native Plant and Tree
Nursery maintain Web pages on the Pueblo of Santa Ana Tribal Enter- ers must learn the length of time required
prises Web site, www.santaana.org. The pages list more than 250 plant to produce marketable crops and how to
species, most grown from locally collected seed. The lists, organized schedule planting so the proper number of
alphabetically by scientific name, function only as a reference to what each species is available for the first year of
the venues stock. Plants must be picked up on-site since the stores are sale and following years (1).
not mail-order businesses.
The Santa Ana Garden Center offers a large selection of drought-toler- Irrigation
ant flowering native plants, shrubs and ground covers for xeriscaping
and trees with low watering requirements. It also stocks native grasses The two most widely used irrigation systems
for lawns or reclamation, herb and vegetable starts, wildflower seed, are overhead and drip or trickle systems.
organic products, drip irrigation supplies, seasonal gift items and books. Overhead irrigation systems are designed
The store can also advise customers about plants for rock gardens, to cover a large area and these systems are
windbreaks, natural hedges, barriers, erosion control, wildlife habitat, the least expensive to install. However, this
food and medicinal uses. method produces uneven water distribution,
Respect for tribal customs and the earth are strongly encouraged when which can slow plant growth, encourage dis-
visiting the nursery and garden center. Taking photographs at the sites ease and contribute to runoff. A container
is restricted, but images at the tribal Web site, www.santaana.org/ nursery using overhead irrigation can use
nursery.htm and www.santaana.org/garden.htm, give an idea of how from 15,000 to 40,000 gallons of water per
some plants are started in hoophouses with supplementary heating
acre daily in the summer (6), a reminder
during the chilly north-central New Mexico winters (5).
that sufficient water is a prerequisite to
nursery production.
Large containers are usually watered with a
field-grown seedlings, is common in both drip or trickle system, which uses 60 to 70
forestry and landscape nursery production. percent less water than an overhead system.
Drip irrigation systems cost more to install
Fifty years ago, nursery managers grew but have superior application uniformity
ornamental plants in the field and dug the and efficiency. Drip irrigation systems are
plants up later for transplanting. Today, 80 also affected less by wind and crop canopies
percent of ornamental plants are container- and produce less runoff. Another advantage
is that workers can continue working while
grown. The switch occurred for several rea-
the plants are being irrigated. The biggest
sons. Container-grown trees have a greater disadvantage to a drip or trickle irrigation
chance for survival and establishment after system, besides the initial cost, is keeping
transplanting. Containerized production the pipes and emitters clean.
does not require good soil and takes up less A third, less-used type of irrigation system
acreage. Containerized stock also enables is subirrigation using capillary sandbeds. In
the grower to extend the planting season. this system, water rises into containerized
Page 4 ATTRA Sustainable Small-Scale Nursery Production

5. Table 2. Comparison of water systems for container nursery stock (7)
Overhead sprinklers Drip or trickle irrigation Capillary beds
tubes
Installation cost/acre Moderate Moderate to high High
Maintenance Low High High
Durability Excellent Low Moderate
Labor Low Moderate to high Low
Water distribution Fair Fair to good* Good
Water use efficiency Poor, very wasteful Good Good
Pump required Large, high pressure Small, low pressure Small, low pressure
Water volume required Large Small Small
Wind effect on distribution Serious None None
*If ground is level and water quality is good
plants through capillary action. The sandbed Out, see the Container production sec-
is covered with at least 1 inch of fine sand tion. For distribution information, see the
and slopes very slightly. Water is released at Resources: Suppliers section. For a list of
the high end and slowly percolates to the low articles related to sandbeds and subirrigation
end. These systems cost the most to install, systems, see Resources: Publications.
but have no runoff or leaching. Plants need to be watered often, especially
Sandbeds are normally built using wood during hot, sunny days. A typical nursery
sidewalls, a plastic bed liner, sand, a small plant in a 1-gallon container can consume
tank, a drainpipe and a float valve. Sand- a pint of water a day, while the growing
beds do not require the use of any electrical medium capacity may be only 1.5 pints.
parts and provide a uniform and consistent One important aspect of irrigation manage-
supply of water without forming a saturated ment is to group plants according to water
water table at the base of the soil column requirements.
in the container. Sandbeds offer efficient
and uniform crop growth while providing Irrigation runoff
less water, less fertilizer and less pesticide. The most important issue with irrigation
Sandbeds also require less labor since in sustainable nursery production is water,
sprinkler heads, timers, pumps, valves and fertilizer and pesticide runoff. Many states
water-treatment systems don’t need to be now have regulations limiting runoff and
monitored (6). groundwater nitrate levels.
The biggest disadvantage of sandbeds is Subirrigation systems are designed to elim-
that weeds and containerized plants grow inate runoff, but overhead and drip or
into the structure. The Agroliner is a retail trickle systems may require special atten-
product designed to alleviate this prob- tion. Ditches planted with grass to slow
lem. The Argoliner is a mat treated with down water flow or tile systems that direct
Spin Out, a copper paint that prevents water to a pond or other holding area can
root growth and is registered by the Envi- collect runoff water.
ronmental Protection Agency. The mat is
The water and some of the fertilizers
placed over the sand and under the con-
present can be recycled by pumping water
tainers.
back out of the holding tank or pond after
Griffin LLC, a supplier of crop protection impurities like sand and silt settle out.
chemicals in Valdosta, Ga., sells Spin Out. Recycled water can improve plant growth.
For more information on ways to use Spin In experiments with more than 100 species
www.attra.ncat.org ATTRA Page 5

6. of ornamentals grown in 2.8-liter contain- practices. The researchers recommend
ers, the mean relative growth of plants irri- using lower amounts of N fertilizer—about
gated with continuously recycled water was 50 milligrams per liter—and providing
103 percent of the control (8). sufficient moisture.
Pulse irrigation is another way to reduce Several Extension bulletins and other pub-
runoff. In this system, a small amount of lications that deal with irrigation runoff
water is applied five or six times a day, issues are accessible on the Internet. See
instead of one heavy watering daily. Very the Resources: Web sites section for more
little water escapes from the container or information.
runs off from the field. Less fertilizer is
applied because there is less leaching. Most
nurseries that use this system use a com- Integrated pest management
puter to control water flow, since watering Integrated pest management is an ecologi-
plants repeatedly by hand causes a huge cally based pest control strategy that is part
increase in labor expenses. of the overall crop production system. It is
called integrated because all appropriate
There are several cultural practices that can methods from multiple scientific disciplines
reduce runoff: are combined into a systematic approach
• Avoid irrigating bare soil for optimizing pest control. Management
• Have rough soil surfaces to provide implies acceptance of pests as inevitable
surface storage of water components at some population level in the
agricultural system (11).
• Use less-porous media that retain
moisture and nutrients An integrated pest management program
involves using resistant cultivars, build-
• Use slow-release fertilizers instead
of liquid fertilizers ing up populations of beneficial organisms,
monitoring numbers of pests, developing
Researchers at The Ohio State Univer- treatment thresholds and using spot treat-
sity conducted experiments to reduce the ments of pesticides that are the least harm-
amount of pesticides and growth regula- ful to beneficial organisms and the environ-
tors leached from nursery pots and trays. ment. It is important to identify pests early
Researchers had excellent success mixing so nursery managers can take appropriate
chemicals in ordinary latex paint and then measures quickly.
painting the interior of the pots. The pots
leached less and the growth regulator and There are numerous publications available
pesticide researchers used, commercially from the USDA’s Cooperative Extension
available brands Bonzi and Marathon, pro- Service that deal with integrated pest man-
vided more consistent control. This method agement for nurseries. See the Resources
also reduced worker re-entry intervals in section for more information.
the nursery area, since workers apply chem-
icals once at the beginning of the growth
process (9).
Reducing moisture stress enhances growth ATTRA publications on nursery-
related pest management topics
more than increasing fertilizer concentra-
tion, a study conducted in the late 1990s Biointensive Integrated Pest Management
found (10). This study, also conducted at Nematodes: Alternative Controls
The Ohio State University, used fertilizer Use of Baking Soda as a Fungicide
concentrations between 50 and 200 milli- Notes on Compost Teas
grams per liter of nitrogen. The research-
Integrated Pest Management for
ers showed that water stress might limit
Greenhouse Crops
growth more frequently than limited nutri-
tion under current container production
Page 6 ATTRA Sustainable Small-Scale Nursery Production

7. Container production NCAT’s Organic Crops Workbook and other
A wide selection of ornamentals is produced ATTRA publications. For information about
in containers. Homeowners usually prefer to whether a commercial product is permitted,
buy containerized plants because the plants restricted or banned in organic produc-
are easier to transport and transplant than tion, consult the Organic Materials Review
balled and burlapped plants. The follow- Institute Web site at www.omri.org.
ing section summarizes some important
container production practices and Containers
addresses sustainable nursery management There are several factors to keep in mind
issues like recycling plastics, weed control when deciding what containers to use. Fac-
and fertilization. tors include cost, design features that con-
The advantages of containerized production trol root growth, durability, shipping capac-
include: ity, availability, how the container affects
growing medium moisture content and tem-
• Achieving high plant densities perature and how the container suits the
• Using land unsuited for field particular needs of the nursery.
P
production ots and
Round, black plastic pots are the industry
• Planting at times independent of the standard, but can cause root constriction containers
weather that leads to plants with poorly developed designed
• Eliminating some operations, like root systems. There are other kinds of con- for enhanced root
root pruning tainers that promote better root systems. growth are an
• Lowering transportation costs Copper-lined, white and light-colored con-
important feature in
because of lightweight media tainers all produce more root growth and
square and stair-step pots help keep plants containerized nurs-
• Experiencing less root loss and a from becoming root-bound (1). ery production.
greater chance of survival than with
field-grown trees Pots and containers designed for enhanced
The disadvantages are also numerous: root growth are an important feature in
containerized nursery production. Each pot
• Small containers need frequent and container offers its own advantages and
watering disadvantages.
• Nutrients deplete rapidly
• Plants require winter protection Copper
• Plants easily become root-bound Foresters discovered that copper can con-
trol root growth. Copper kills root tips that
• Wind can knock over trees
come in contact with it, forcing roots to
• Containers are costly branch within the root ball instead of cir-
• Labor costs to pot up plants are cling around it.
high Plants grown in copper-treated containers
• Temperature extremes stress roots are taller, less root-bound and have higher
Growing certified organic nursery stock transplant survival rates. Plants grown
intended for sale to vineyards, berry farms in copper-treated containers also have
and orchards raising organic produce is a increased nitrogen recovery and require
niche market that requires special atten- fewer applications of nitrogenous fertilizer.
tion. Restricted products include common More than 120 species perform better in
ingredients in conventional nursery produc- copper-treated containers versus untreated
tion like chemical fertilizers, wetting agents, containers. Copper-treated pots also do not
herbicides and synthetic insecticides and leach or leach very little into groundwater
fungicides. For more information, refer to or soil.
www.attra.ncat.org ATTRA Page 7

8. Copper-treated fiber pots, made from recy- strong tap-rooted species such as black wal-
cled paper, are biodegradable and can nut, pecan and pines for Christmas trees.
even be composted. The main problem with
There are other types of containers that
fiber pots is that the pots can degrade too
promote excellent root branching and dis-
quickly. Research at The Ohio State Univer-
courage root circling. RootMaker, devel-
sity showed that incorporating copper into
oped by Dr. Carl Whitcomb at the horticul-
fiber pots can increase their longevity (12).
ture research company Lacebark, Inc., is a
Dr. John Ruter at the University of Georgia
pot that encourages root branching. Root-
found copper-treated fiber pots keep roots
Maker pots have staggered walls and a stag-
cooler in the summer, increase root dry
gered bottom, which prevent root circling
weight and shoot dry weight of several spe-
and direct roots toward holes in the walls
cies and can withstand shipping (13).
and bottom of the pots. Whitcomb, formerly
Griffin LLC, a supplier of crop protection head of the nursery research program at
chemicals in Valdosta, Ga., offers a product Oklahoma State University, is well known
called Spin Out, a copper paint registered by for his numerous innovative approaches to
the EPA. Root Right pots are round, black unusual container systems.
plastic pots manufactured with Spin Out as a
G
rowing tree component of the container walls. For more Tubes
seedlings in information on Spin Out and Root Right pots,
Long bottomless tubes are another produc-
contact the Lerio Corporation (14).
bottomless tion system that uses air root pruning. Tubes
paper-based milk are generally made of plastic or Styrofoam.
Bottomless pots Nurserymen can use single tubes or several
cartons is one way to
use air root pruning.
Air root pruning is another way to prevent tubes imbedded in a flat. Tube plants range
root circling. Air root pruning employs a in size from large plugs sold as nursery lin-
similar mechanism to copper-treated pots. ers to seedling trees grown in long, narrow
Root tips that come in contact with air are pots and sold directly to consumers. Tubes
killed and the root system branches out are popular because they allow massive plant
within the root ball. quantities to grow in a small area. Tubes are
particularly adaptable to small-scale nurs-
Growing tree seedlings in bottomless paper-
ery production and to specialized stock like
based milk cartons is one way to use air
perennials and tree seedlings.
root pruning. The milk carton, when folded
open, creates a long, bottomless container. For more information on containers, see The
These containers are placed in a wooden Container Tree Nursery Manual, Volume 2, by
fl at with a wire-screen bottom and then Landis et al., listed in the Resources: Pub-
fi lled with a soilless nursery mix. Another lications section. For suppliers of unusual
option is to place tree seedlings in plastic pots, see the Resource: Suppliers section.
milk crates. The taproot grows downward
and out through the bottom of the container. Pot-in-pot system
The root tip is exposed to the air, desiccates
The pot-in-pot production method alleviates
and dies back.
some of the problems associated with con-
Repeated air-root pruning stimulates lateral tainer production, such as blow-over and
branching and results in a fibrous root sys- moisture loss (15). This system involves
tem as opposed to a strong taproot system. burying a holder pot, or moat pot, in the
The benefit to the tree is rapid establishment ground and placing a containerized plant
in the field or landscape with increased inside this pot. The main drawback to this
scaffold branching and top growth. Nursery system is the high initial cost of the moat
stock production by the milk carton method pot. The moat pot is a long-term investment
is especially useful for on-farm tree produc- since it will last 15 years or more. For more
tion and can be used in the propagation of information on pot-in-pot systems, see the
a wide range of woody plants, including articles listed in the Resources section.
Page 8 ATTRA Sustainable Small-Scale Nursery Production

9. A container system that emphasizes hardy, fibrous roots
Cherry Lake Tree Farm in Groveland, Fla. Inc. (17). Larger liners are planted in pruning fabric developed by Cherry
developed a better way to grow con- Tree Bands, available from Anderson Lake and manufactured by Root
tainerized trees (16). Their patented Die and Manufacturing (18). Before Control, Inc. in Oklahoma City (19). The
Root-Enhancement System focuses planting, all the trays are sprayed with fabric lowers root zone temperatures
on growing trees with a fibrous, lateral Spin Out, a copper paint registered by and prunes roots.
root system. the EPA. When the trees reach an appropriate
In the first stage, small liners grow in The liners are inspected before size, workers place them in pot-in-pot
Deep Groove tube cell-pack trays of 38 potting. Workers cull liners with weak containers or transplant the trees into
or 51 cells. The cells are cone-shaped root systems and place the rest in growbags. Finally, workers put the trees
and lined with four vertical ridges that 1- or 3-gallon containers. These pots in a Spin Out-treated container in prep-
guide plant roots to a large hole at the contain grids that sit about 1 inch aration for sale.
bottom. These trays sit on benches in
above the bottom of the pots and For a video of how this system works,
the greenhouse.
air-prune the roots. Container sleeves visit the Cherry Lake Tree Farm at www.
Deep Groove tube cell-pack trays also hold the roots. The sleeves cherrylake.com/Resources/Resources-
are available from Growing Systems, are made of a reusable geotextile Airpot.htm.
Recycling plastic Many recyclers require nurseries to gather
a certain amount of plastic before sending
Most nurseries use lots of plastic in the form
a truck to pick it up. Smaller nurseries may
of pots, flats, hanging baskets and green-
have trouble storing a large amount of plas-
house fi lm. The nursery can reuse some of
tic. Try combining plastic waste with other
these products, but it’s important to have
growers in the community. Some recyclers
a recycling system in place. Buying multi-
will not pay the grower for the plastic but do
year, ultraviolet-stabilized greenhouse fi lm
not charge for transportation costs, which
decreases the amount of sheet plastic used
are often high.
each year, but this kind of film is very expen-
sive and not always readily available (20).
Weed control
Fortunately, there are a number of recyclers
Weed control is extremely important in con-
around the country that accept nursery
tainer production. Weeds compete for water
plastic. The Plastics Division of the Amer-
and nutrients and hinder sales of nursery
ican Chemistry Council Web site, www.
stock. Weed control efforts should focus on
americanchemistry.com/s_plastics, provides
two areas: in the pot and under the pot.
a wealth of helpful information on recycling
of plastics. The plastics division also main- Sanitation is the least costly and most effec-
tains the United States and Canada Recy- tive method for controlling weeds. To pre-
cled Plastic Markets Database with con- vent weed seeds from blowing into pots, a
tact data for plastic recycling centers on a vegetation-free zone on and surrounding the
state-by-state basis. The Web site is www. production bed is critical. To keep weeds
americanchemistry.com/s_plastics/sec_rpmd. from growing under the pot, place pots on
asp?CID=1591&DID=6053. Recyclers that geotextile weed barriers, often called fab-
accept agricultural plastics often have cer- ric weed barrier or landscape cloth. Mod-
tain restrictions. Recyclers may require ern landscape cloths are durable and can
clean sheet plastic, which often means wash- last for 10 to 12 years in full sun. Land-
ing plastic before storage. Plastic must also scape cloths do an excellent job of control-
be stored indoors properly. Most hard plas- ling weeds and are permeable to water from
tics like plug trays, flats, pots and hanging irrigation and rainfall, so drainage is not a
baskets are either No. 6 polystyrene or No. problem. Although the initial cost is high,
2 high-density polyethylene. This distinc- the expense can be prorated as an annual
tion is important to some recyclers (20). weed control investment.
www.attra.ncat.org ATTRA Page 9

10. Hand weeding is costly, but it may be appro- Alternatives to herbicides
priate in a small nursery setting. Weeds
Fabric weed barrier disks can control weeds
must be removed when they are small since
in containers. The fabric disks are pre-slit
large quantities of media are lost when pull-
and fit on top of the pot around the plant
ing big weeds out of containers.
stem. Barrier disks prevent weeds from
Herbicides are widely used in container growing in containers by excluding sunlight
nursery production. Growers use a weed- and inhibiting weed germination. The disks
free medium to establish nursery plants, are permeable to air and water but prevent
but wind, birds and surface irrigation water germination of troublesome container nurs-
all deposit weed seeds onto the pot surface. ery weeds like oxalis. The disks also reduce
Broadleaf and grassy weeds love to get a evaporation.
free ride into a container nursery because
growing conditions in a media-rich pot are Tex-R Geodiscs are fabric disks treated with
perfect. Pre- and post-emergent herbicides Spin Out. Geodiscs prevent weed growth
are commonly used in commercial nursery by excluding light and pruning the roots of
production to control these opportunists. weed seeds that land on the fabric. Geodiscs
provide effective weed control for up to three
In 1991, Monrovia Nursery, with headquar- years and can be moved from pot to pot. For
ters in Azusa, Calif., compared hand weeding distributors, contact Texel USA (22).
to spraying herbicides and found that a com-
bination of the two is the least-costly method Bonnie Appleton, director of the horticul-
(21). See Figure 1 below. Monrovia found it ture master’s degree program at Virginia
took workers 10 hours of hand weeding per Tech, recently conducted research using
acre, performed 10 times a year, to keep the Geodiscs on container-grown willow oaks
nursery weed-free without using pre-emergent (23). The Geodiscs suppressed all weeds
herbicides. By using a pre-emergent once in completely. Trees grown in the pots with
the spring and once in the fall, the workers Geodiscs had higher top dry weights and
only needed to perform hand weeding seven root dry weights than trees grown without
times a year, spending one hour weeding each any form of weed control and trees sprayed
acre. Monrovia paid workers $8 an hour, the with a conventional herbicide.
cost of herbicide was $200 per acre per appli-
cation and it took two hours to apply. The Bioherbicides
Field production section below has more
Corn gluten meal, a recently introduced
information on weed control.
weed control, is a by-product of corn syrup
processing. Corn gluten meal is a pre-emer-
Figure 1. Courtesy of American Nurseryman (21). Used with permission. gent herbicide applied in early spring. The
Weed-Control Options meal works best when applied to the top
one-quarter inch of soil and must be reap-
Annual Weed-Control Cost Per Acre (in dollars)
900
800
plied every year. Corn gluten meal is 10
percent nitrogen and acts as a slow-release
700
fertilizer for the crop. Corn gluten meal is
600 patented and sold as an herbicide. See the
500 Resources: Suppliers section for corn
400 gluten meal suppliers. Treating a large area
300 can be quite expensive. Wheat gluten meal
200 has many of the same effects as corn gluten
100
meal, but it has not been patented and may
be more affordable.
0
0 Applications 2 Applications 4 Applications
Recent research revealed that corn glu-
Number of Herbicide Applications per Year
ten hydrosylate, which is made from corn
Herbicide Cost Herbicide Application Labor Cost Hand-Weeding Cost gluten meal, is more effective controlling
Page 10 ATTRA Sustainable Small-Scale Nursery Production

11. weeds than corn gluten meal (24) and can Final Rule, more nursery growers explore
be applied at less than half the rate for fertilizers acceptable in organic production.
effective weed control. Iowa State Univer- ATTRA also has several publications on the
sity, the patent holder of corn gluten meal topic, including Potting Mixes for Certified
as a natural herbicide, maintains a list of Organic Production. Unlike synthetic green-
licensed suppliers for this product at www. house fertilizers, there is minimal research
techtransfer.iastate.edu/en/for_industry/tech- to support the use of organic fertilizers in
nology_search/cgm_licensees.cfm. See the a nursery mix recipe. Most of the follow-
Resources: Suppliers section for informa- ing material will focus on organic fertilizers
tion on purchasing corn gluten hydrosylate. for container nursery production. In sus-
There are some new environmentally tainable nursery production the emphasis is
friendly contact herbicides that break down eliminating runoff, regardless of if the fer-
quickly and provide options for weed con- tilizer source is synthetic or organic. Exces-
trol in container nurseries around irriga- sive nitrates and phosphorus are the most
tion risers and perimeter areas and are also common problems in runoff water (25).
applicable for general use in field nursery There are four basic ways to fertilize con-
production. One class of products is made tainerized plants: incorporate, topdress,
from pelargonic acid, a fatty acid found in liquid feed and foliar feed. In a nursery
plants and animals. Available commercial container, fertilizer incorporation in the
products include Weed Eraser and Scythe. nursery mix combined with liquid feeding
The products are sprayed on weeds and rap- should provide sufficient nutrition.
idly lower the weeds’ pH level, weakening
cell walls and killing the weeds within two Several organic fertilizers provide nitro-
hours. A second class of products contain gen. Fertilizers include alfalfa meal, blood
acetic acid (vinegar), lemon juice, eugen- meal and cottonseed meal, among others.
gol, thyme oil, orange oil and other natural Materials that provide phosphorus include
ingredients. Commercially available prod- oak leaves, bone meal and shrimp wastes,
ucts include Nature’s Glory, Burnout and among others. Greensand, granite meal and
Bioganic. The products work as contact her- soybean meal all provide potassium. Table 3
bicides and control, with varying degrees of is not exhaustive, but it provides analyses of
success, broadleaf and grassy weeds. Appli- some popular organic and synthetic slow-
cation to nursery plants should be avoided release fertilizers.
and several applications may be necessary Maintaining adequate levels of nutrients in
to kill perennial weeds. the container medium is necessary for opti-
mum growth of woody ornamentals. The
Fertilization levels of soluble nutrients in containers can
Large-scale container nursery production is be significantly reduced after three or four
a huge success largely due to advances in irrigations because of limited container vol-
media and fertilizer combinations. Favor- ume and frequent application of water. Use
able media and fertilizer combinations are slow-release and liquid fertilizing systems to
a result of several decades of research col- overcome this problem.
laborations between land-grant universi- Organic or synthetic slow-release fertilizers
ties, commercial nurseries and the fertilizer
help cut down levels of nitrates in runoff water
industry. Commercial synthetic fertilizers
(1). Slow-release and controlled-release syn-
including slow-release and liquid fertiliz-
thetic fertilizers, like commercially available
ers play a key role in this picture. Detailed
Nitroform and Osmocote, are common in con-
information on commercial nursery mixes
tainer production systems. Incorporate slow-
and fertilizer systems is available through
release and controlled-release fertilizers into
the Cooperative Extension Service.
the growing media for best results. Do not top-
As organic production becomes standard- dress. Slow-release fertilizers are often used
ized under the National Organic Program in combination with liquid fertilization.
www.attra.ncat.org ATTRA Page 11

12. Table 3. Analysis of organic and synthetic slow-release fertilizers
Organic fertilizers %N %P %K Other nutrients
Bat guano (fresh) 10 3 1 Calcium
Bat guano (old) 2 8 0 Calcium
Blood meal 10 0 0
Bone meal (steamed) 1 11 0 Calcium
Cottonseed meal 6 2 1
Eggshells 1.2 0.4 0.1 Calcium and trace minerals
Fish emulsion 4 1 1 Sulfur
Fish meal 5 3 3
Greensand 0.0 0.0 7.0 32 trace minerals
Hoof and horn meal 12 2 0
Kelp meal 1.5 0.5 2.5 Trace minerals
Manure
Cow 2 2.3 2.4
Horse 1.7 0.7 1.8
Pig 2 1.8 1.8
Sheep 4 1.4 3.5
Poultry 4 4 2
Oak leaves 0.8 9.4 0.1
Pine needles 0.1 0.0 0.5
Sawdust, well rotted 0.0 0.2 0.2
Soybean meal 7.0 0.5 2.3
Worm castings 0.5 0.5 0.3 11 trace minerals
Slow-release synthetic fertilizers Effective period
IBDU 31 0 0
Lesco 20 6 12 4-6 months
MagAmp
(also contains 25% 8 40 0 100 days
magnesium)
Osmocote 13-19 6-14 12-14 3-4 or 8-9 months
Precise 12 6 6 3-4 months
Premix (also contains
24 7 8 6-8 weeks
micronutrients)
ProKote 20 3 10 7-9 months
Sta-Green 12 6 6 6-8 weeks
Page 12 ATTRA Sustainable Small-Scale Nursery Production

13. Table 4. Materials for organic fertigation*
Element Material Benefits
Nitrogen Liquefied fish Biostimulant, balanced NPK
Liquid manures Rapid uptake
Phytamin 800 Rapid uptake, high solubility
Sodium nitrate** Rapid
Spray-dried fish** Rapid uptake, biostimulant
Phosphorus Bat guano** Rapid uptake
Micronized rock phosphate** Biostimulants, 16% P2O5
Seabird guano** Rapid uptake, 10% P2O5
Potassium Soluble Sul-Po-Mag** Supplies K, Mg, and S
Soluble sulfate of potash** 50% K, 18% S
N-P-K combination Fish products
Liquefied manures
Phytamin 3-2-3 Rapid uptake
Seabird guano** 12-12-2.5
Calcium Solution grade gypsum** Calcium and sulfur
Solution grade limestone** 98% CaCO3
Sulfur Micronized sulfur** Up to 90% S
Solution grade gypsum**
Trace mineral/ Compost teas Biostimulant, humic acids
biostimulants
Kelp extract powders** Trace minerals, biostimulant
Kelp extract liquids Trace minerals, biostimulant
Liquid humates Humic acids, biostimulants
Liquid trace minerals Various formulations
Micronized compost** Biostimulant, humic acids
Micronized humates** Humic acids, biostimulant
Rock dusts** Trace minerals, biostimulant
*Reprinted with permission from Amigo Cantisano. 2000. Organic growers can fertigate! Growing for Market.
March. p. 8-9.
**Dry material: Must be premixed and thoroughly agitated in water prior to and during injection. May be less soluble than
liquid formulations.
Nitrogen is the main nutrient supplied do not clog drip emitters and microsprin-
through liquid feeding, or fertigation. klers (26). Fish protein, blood protein,
Organic liquid fertilizers include fish emul- poultry protein and brewers yeast are all
sion, fi sh powder, blood meal, bat guano, available as spray-dried materials. Amigo
seabird guano, worm castings and compos- Cantisano, an organic agriculture con-
ted manure teas. Some forms of organic fer- sultant in California, compiled Table 4
tilizers are more adaptable to low-volume (27).
irrigation systems like drip or trickle sys-
tems. A 1992 study found that spray-dried Foliar feeding can supplement soil and liq-
fi sh protein and poultry protein fertilizers uid fertilization, especially where certain
www.attra.ncat.org ATTRA Page 13

14. nutrients are deficient and must be incor-
porated into the plant quickly. Use fi ltered Chris Starbuck, extension specialist at the
solutions of manure, seaweed, fish powder University of Missouri, developed the Mis-
and fish emulsion. Seaweed is an excellent souri Gravel Bed as an alternative growing
system for nursery stock (29). The gravel
foliar material because it contains growth
bed uses a mixture of gravel and sand to get
hormones, including auxins, gibberellins young plants established. The gravel bed is
and cytokinins, as well as trace elements. inexpensive because it uses neither contain-
Research suggests that foliar feeding pro- ers nor potting mix, but produces healthy
grams enhance plant resistance to pest and bare-root plants.
disease attack. Compost teas are popular as The gravel bed uses half-inch or smaller
a foliar feed primarily because of their dis- gravel mixed with 10 to 15 percent sand
ease-suppressive characteristics. and is 14 to 18 inches deep to support 1.5-
inch caliper trees. Starbuck places dormant,
For more information on alternative fertil-
bare-root plants in the bed in early spring.
izers, request the ATTRA publication Alter- He applies slow-release fertilizers on top of
native Soil Amendments and the Web-only the gravel. Starbuck leaves plants in the bed
database Sources of Organic Fertilizers and for at least six weeks, but pulls the plants the
Amendments. Another useful resource is year they are planted. He uses an automatic
Fertile Soil by Robert Parnes (28), an in- trickle irrigation system.
depth publication on organic fertilizers. Starbuck helped growers in more than 40
Parnes’ publication provides detailed tables states establish gravel beds for their opera-
on the nutrient content of various manures tions. A grower in Iowa successfully overwin-
and plant and animal by-products. tered plants in temperatures as low as minus
25 degrees Fahrenheit. The roots are as pro-
tected in gravel as they would be in soil and
Potting media are more protected than they would be in
Field soil is sometimes used in container containers.
mixes. Field soil makes up 10 to 30 percent
of the mix by volume, but soil is heavy and
requires the additional step of pasteuriza- Mycorrhizae are soil fungi that form benefi-
tion to eliminate diseases and weed seeds. cial associations with plant roots. Mycorrhi-
The standard replacement for soil is peat zae enable plant roots to do a better job of
moss, but there is concern that peat is a gaining nutrients and water. The fungi can
non-renewable resource. Research is being be used in field or container production.
conducted to determine what materials can Growers achieve better stand establishment,
be used to replace peat. Most of the prod- use less fertilizer and inoculate bare-root
ucts being tested are some form of waste. seedlings when using mycorrhizae. Com-
mercially available mycorrhizae stimulate
Composted pine bark, a by-product of the
the roots of almost all tree and shrub spe-
lumber industry, is an excellent medium
cies. For a listing of suppliers of mycorrhi-
for containerized plants. Mixes containing
zae, see ATTRA’s Sources of Organic Fertil-
more than 20 percent composted pine bark
izers and Amendments.
support a significant level of suppression
of Pythium damping-off (30). Other alter-
natives are coir, spent mushroom compost, Field production
paper mill sludge, apple pomace, shredded Until the 1950s, virtually all nursery pro-
newspaper, compost, processed alfalfa, pro- duction occurred in the field. Field produc-
cessed kenaf, recycled cardboard and com- tion is still widely used to produce bare-root
posted municipal yard waste. Most studies seedlings for conservation plantings, fruit
show that these alternative products should trees and nursery liners. The most profit-
not compose more than 50 percent of the able product of field nurseries is bagged
mix. For in-depth information on these top- and burlapped shade trees for the land-
ics, ask for the ATTRA publication Potting scape industry. In-ground production is
Mixes for Certified Organic Production. advantageous to tap-rooted tree species,
Page 14 ATTRA Sustainable Small-Scale Nursery Production

15. mass plantings, inexpensive establishment The advantages of field grow bags are
and large caliper (trunk diameter) size. Dis- numerous. Bags enhance rooting, leave 80
advantages of in-ground production include percent of roots intact during transplant-
a higher percentage of plant loss and longer ing, make harvesting easier, save labor and
establishment periods after transplanting. time, do not require special machinery at
harvest and can be harvested year-round.
Field nursery production involves the use Bagged and burlapped plants are normally
of unique soil management practices. Soil- harvested only during dormancy (31).
building cover crops and crop rotations are
important to maintain good soil structure, There are also disadvantages. The initial
fertility and organic matter. Living mulches investment in grow bags is expensive, plants
are cover crops planted in the aisles to hold need more staking and water after trans-
the soil, provide traction, increase water planting, damaged bags cannot be used,
infi ltration and suppress weeds. Legume mechanical cultivation and precise fertilizer
cover crops fi x nitrogen and can be used application are difficult and bag removal can
to reduce the amount of nitrogen fertilizer be difficult and time consuming (31).
applied each year. See ATTRA’s Overview The greatest disadvantage of growing in
I
of Cover Crops and Green Manures for fur- bags is marketing the plants. Few people ntegrating
ther information and resources. know the advantages of growing in bags and living mulches,
Integrating living mulches, cover crops and find bagged trees less convenient to handle cover crops and
the application of high-quality composts in than containerized trees. One way around
this is to grow the plant in a pot for the last the application of
field nursery operations are the fastest ways
to improve nursery soil. To reduce pest year of production. high-quality
problems, plant a diversity of species rather composts in field
An important consideration in bagged and
than a large block of single species followed burlapped production is the loss of 200 to nursery operations
by a large block of another species. Habitat 250 tons of topsoil per acre at each har- are the fastest ways to
management for beneficial insects is also an vest. The digging and removal of topsoil improve nursery soil.
option in a field situation. For more infor- from bagged and burlapped nursery oper-
mation on this, see ATTRA’s Farmscaping ations is a practice that can, over a long
to Enhance Biological Control. time, seriously deplete the farm’s most
Nursery equipment and irrigation systems important resource. There are two ways to
for field nursery production are unique. fight topsoil depletion. Replace topsoil with
Suppliers are listed in the trade publication something else or have a bare-root opera-
Nursery Management and Production Buyer’s tion that does not require topsoil to leave
Guide and in the magazine American Nurs- the farm. Many growers use compost to
eryman. See the Resources: Publications replace some of the topsoil that is lost, but
section for contact information. applying more than 40 tons of compost per
acre is not recommended.
A recent innovation in field nursery
product ion is the use of in-g round Weed control
fabric containers, sometimes called root
control bags or field grow bags. Dr. Carl Weed control in modern field nursery pro-
duction is based on the use of herbicides.
Whitcomb, formerly head of the nurs-
There are many excellent non-chemical alter-
ery research program at Oklahoma State
natives, however. These include mechanical
University, developed these containers in
cultivation, flame weeding, mulches, living
the early 1980s. The bags have a fabric
mulches, steam and solarization.
or clear polyethylene bottom stitched or
glued to walls made of non-woven fabric
and come in several sizes (31). In theory, Mechanical cultivation
the bags combine the best qualities of Bärtschi-Fobro (32), a Swiss manufacturer
container and field production. of nursery equipment, offers small-scale
www.attra.ncat.org ATTRA Page 15

16. implements including a brush hoe for preci- inches wide, from 1/2 inch to 10 inches
sion weeding in multiple-row seedling nurs- deep.
ery beds. The company also makes brush
Landscape fabric can also be used in field
heads that disturb the soil surface and dis-
production. A fast way for growers to get
lodge weed seedlings as the drum turns.
into production is to lay cloth in the field,
The company no longer has a U.S. distribu-
cut or burn holes in the cloth and then plant
tor, but small-scale implements may still be the liners or seedlings.
available through used-equipment dealers.
Researchers at Oregon State University
Flame weeding found that mulches made of oyster shell,
hazelnut shell and copper-treated geotex-
Flame torches, or flamers, may be an option tiles provide good suppression of liverwort,
in some nursery situations. Flaming works a prevalent weed in many nurseries. These
by searing and disrupting plant cells, not three mulches outperformed mulches of
by burning plant tissue. Passing a flamer rockwool, peat moss, coarse sand, perlite,
quickly over a weed is enough to kill the top pumice and the commercial herbicide Ron-
of the weeds, but roots can re-sprout new starand Surflan. The mulches also outper-
F
lame weeders growth. Broadleaf weeds are more suscep- formed iron oxide, copper sulfate and man-
can be used
tible to flaming than grassy weeds. Flam- ganese sulfate fertilizers (35).
ing needs to be repeated every two to three
to prepare
weeks to control grasses.
a stale seedbed by Living mulches
flaming off the first
Flame weeders can be used to prepare a In a 1990s study conducted in Minnesota,
stale seedbed by flaming off the fi rst and researchers compared soil cultivation, her-
and second flushes
second flushes of weeds to emerge after bicides and three living mulches for weed
of weeds to emerge seedbed preparation. Weed fl amers can suppression in a field with six species of
after seedbed also control post-emergent weeds. To pro- ornamental trees (36). The researchers
preparation. tect young seedlings from injury, use flam- used Norcen bird’s-foot trefoil, Wheeler
ing shields. Taller seedlings and trees with winter rye and a grass sod consisting of
well-developed bark can withstand directed 80 percent Eton perennial ryegrass and
fl aming aimed at weeds growing in and 20 percent Ruby red fescue. The grass sod
between the rows. Although there is some provided excellent weed control, but was
criticism that flaming is not a sustainable overly competitive with the trees. The tre-
practice because it uses fossil fuels, flame- foil was infested with weeds. The winter
killing a nursery bed or field of seedlings rye, which was killed with herbicides and
uses less fossil fuel than manufacturing, then acted as a mulch, provided good weed
transporting and spraying an herbicide for control and increased water infi ltration and
the same job (33). For more information soil moisture. That evened out soil tempera-
on flaming, contact ATTRA at 1-800-346- ture fluctuations, reduced soil bulk density,
9140 or www.attra.ncat.org. improved nutrient cycling and reduced field
maintenance costs. In general, the cover
Mulches crops tended to reduce annual weeds and
Mulches are another way to exclude weeds. favor perennial species.
Mulches keep out weeds by limiting light
and retaining moisture in the soil. Organic Steam
mulches should be 3 to 4 inches thick and For years, conventional production systems
need replenishing once or twice a year. used methyl bromide to sterilize soil before
Millcreek Manufacturing, based in Leola, planting. One sustainable system that yields
Pa., offers a row mulching machine that the same results uses steam to disinfest
can apply mulch and compost to field- beds and greenhouses prior to planting. In
grown stock (34). The machine costs about a field planting, this system can treat plant-
$5,000 and can mulch beds from 18 to 48 ing beds. Steam is nontoxic, easy to apply,
Page 16 ATTRA Sustainable Small-Scale Nursery Production

17. Table 5. Organic mulches
Type Source of weeds Comments
Grass clippings Yes Usually free, not very attractive
Inexpensive, very effective, not very attractive, can
Newspaper No
attract slugs
Very expensive, decomposes in 2-3 years, adds high
Cocoa hulls No
amounts of potassium
Cottonseed hulls No Expensive, not available everywhere
Decomposes in 2-6 years, chunks are bulky and can
Pine bark nuggets No
wash away
Shredded softwoods (cedar, No Price depends on local availability, attractive, decom-
cypress, etc.) poses in 2-5 years
Can be quite inexpensive if obtained from chipped
Hardwood chips No
shrubs or trees, decomposes in 1-3 years
Compost No Available, attractive
Corn stalks No Not available everywhere, unattractive
Wheat straw Yes Inexpensive, decomposes rapidly
Hay Yes Inexpensive, decomposes rapidly
Rice hulls Yes Not available everywhere
Pine straw Yes Inexpensive, attractive, decomposes in 1-2 years
Leaves Yes Usually free, compost first
Cardboard No Inexpensive, lasts a long time
Inexpensive, depletes nitrogen, can blow away, better
Sawdust No
to use aged material
controls the same soil pests as conventional Solarization
methods and works in a wide variety of cli-
Soil solarization is another option for kill-
mates and conditions (37).
ing pests before planting trees, shrubs or
A small portable boiler is the best unit to perennials. Treat only beds that will be
use for a greenhouse. The Sioux Steam planted. The basic principle of solarization
Flo, available from the Sioux Corporation, involves stretching sheets of clear plastic
will work for greenhouse operations and across moist ground. Solar radiation heats
costs about $5,700. For small beds in the the soil and kills pests, including weed
field, larger units are available from Saska- seeds and harmful insects. Solarization
toon Boiler Manufacturing in Canada. See
can kill annual and perennial weeds if
Resources: Suppliers for contact infor-
summer temperatures climb high enough.
mation. The important differences in steam
machines are how much heat the machines Solarization can also be used to disinfest
put out, how portable the machines are reused or soil-based potting media. To
and how far into the soil the steam pen- do this, enclose the media in plastic bags
etrates. Although most machines heat only and leave them in the sun for two to three
the top 3 to 6 inches of soil, temperatures weeks. Two layers of plastic kill more
are high enough to kill most weed seeds. pests and work about four times faster
Machines that heat the soil to 140 degrees than one layer (38). For more information
for at least 30 minutes kill pest fungi, on soil solarization, contact ATTRA at
bacteria, nematodes and weed seeds. 1-800-346-9140 or www.attra.ncat.org.
www.attra.ncat.org ATTRA Page 17

18. Harvest and storage • Prices and quantities offered by
competitors
At some point, nurseries must dig up field-
grown trees and plants. See the Resources: • Supply and demand for the crop,
Suppliers section for manufacturers of tree except prices for high-quality prod-
diggers. Plants are often stored after dig- ucts and loyal customers (1)
ging. Conventional production systems dig The British Columbia Ministry of Agricul-
trees in late fall or early winter and store ture, Fisheries and Food compiled a Plan-
trees in warehouses until early spring. Dur- ning for Profit series of online publications
ing this time, nurseries spray bare-root that details costs involved in establishing
trees with fungicides and bacteriostats to and growing several nursery species. These
keep problems from arising. enterprise budgets provide information on
expenses and income for perennial and tree
Researchers in Rhode Island experimented crops grown in containers and in the field.
with Taxus bagged and burlapped stock to The guides provide a rough idea of how
prevent the plants from rooting out, a con- much it costs to start production and how
dition where the roots grow into the burlap long it takes to make a profit. See the minis-
O
bags. They used Spin Out, an EPA-approved try’s Web site at www.agf.gov.bc.ca/busmgmt/
ne way copper paint, in several different ways (39). budgets/index.htm for more information.
to cut Treatments included painting the bottom
produc- of the root ball with copper paint, setting For costs associated with establishing a
the root ball on copper-treated burlap and small perennial nursery, see the handbook
tion costs is to grow
rewrapping the root ball with copper-treated Requirements and Costs of Establishing and
plants in smaller Operating a Three-Acre Herbaceous Perennial
burlap before mulching. Although all these
containers.
treatments provided good control of rooting Container Nursery listed in the Resources:
out after 12 to 16 weeks, the most effec- Perennials section. See Betrock Informa-
tive treatments were setting the root ball tion System’s Web site hortworld.com for a
on copper-treated burlap and leaving it list of horticultural software that focuses on
plant selection and nursery management.
unmulched. The researchers also found that
placing the root balls on TexR Agroliner, a Competitive prices can fall below the cost
Spin Out-treated non-woven fabric, stopped of production. In this circumstance, a nurs-
rooting out completely. ery with a unique advantage, like proximity
to its market or a superior product, may be
Costs able to maintain a higher price that covers
costs without experiencing a serious drop in
The costs of nursery production include the number of plants sold.
overhead, direct and marketing costs. Over-
head costs include all the general costs of Although it is desirable to make a profit on
operating the nursery, like taxes, depre- each kind of plant, sometimes it is good
ciation, interest, rent, utilities, insurance, marketing strategy to grow some plants
maintenance and repair, new construction, that may not be profitable in order to offer
new equipment, supplies, managerial and a well-rounded inventory. A small nurs-
administrative salaries and labor wages that ery might specialize in a few high-quality
cannot be assigned to a particular crop. plants or produce some plants not carried
Direct costs are tied to a crop, like pur- by larger nurseries, which produce only
chasing seed, potting media and fertilizers. plants with high sales volumes.
Keeping excellent records is the best way to One way to cut production costs is to grow
accurately determine true costs. plants in smaller containers. Although the
Prices should reflect: crop sells for less, the costs of media and
containers are reduced, as well as the time
• Exact production costs that include needed to produce the crop. Selling plants at
a reasonable profit for each crop wholesale prices means less money received
Page 18 ATTRA Sustainable Small-Scale Nursery Production