This document provides information on suitable crops for fall vegetable production, including warm weather crops that can be harvested in fall, cool weather crops that can be planted and harvested in fall and winter, and overwinter crops for early spring harvest. It discusses scheduling planting times for various crops to extend the harvest season, considering factors like temperature requirements, days to maturity, and frost dates. Cool weather crops recommended for fall include beets, carrots, greens, and root vegetables.
2. What’s in This Presentation
A. Suitable crops for harvesting or planting in fall:
o Warm weather crops for fall harvest
o Cool weather spring/fall crops
o Cold-hardy crops to plant in fall and harvest in
winter
o Overwinter crops for early spring harvest
o Winter hoophouse crops
B. Meeting the challenges of each season
C. Lots of Resources
D. My contact information
3. Extend the season without
overextending yourself!
• Find the balance point at which the time, money
and energy you put in are still definitely
worthwhile. The further you try to extend the
season of a crop beyond what is normal for your
climate, the more energy it takes and the less
financially worthwhile it becomes.
• An extension of two or three weeks takes only a
little extra vigilance and a modest investment in
rowcover .
• It’s much easier to get extra fall harvests for a
month or two from mature plants you already
have, than it is to get harvests a week earlier in the
spring.
• A longer harvest season helps you retain and
satisfy customers
• and can help provide year-round employment for
your crew, which helps you retain skilled workers.
• The pace is naturally slower - it’s not a second
hectic summer: few weeds germinate and
established crops need less attention.
Tired but unbroken. Credit Bridget Aleshire
4. Suitable crops for harvesting or planting in fall
Warm weather crops
for fall harvest:
• green beans, edamame
• cucumbers
• zucchini, summer squash
• cantaloupes (muskmelons)
• sweet corn
• tomatoes
Green beans. Credit Kathryn Simmons
5. Formula to determine last safe
planting date for frost-tender crops
Count back from the expected first
frost date, adding:
• the number of days from seeding
to harvest,
• the average length of the harvest
period,
• 14 days to allow for the slowing
rate of growth in the fall, and
• 14 days to allow for an early frost
(unless you have rowcover -
there is often a spell of warmer
weather after the first frosts, and
you can effectively push back
your first frost date.)
Zephyr Summer Squash
CREDIT: Kathryn Simmons.
6. Example: Yellow Squash
• number of days from seeding to harvest 50
• average length of the harvest period 21
• 14 days to allow for the slowing rate of growth in the fall 14
• 14 days to allow for an early frost (but we have rowcover) 0
days before the first frost = total of these = 85
last date for sowing, with October 14 first frost date = July 21
But using rowcover to throw over the last planting during cold spells, the growing
season is effectively 2 weeks longer, and we sow our last planting of squash on Aug 5.
We sow our last sweet corn
July16 (90 days before our
average first frost) and we
harvest from around Sept 22.
We sow our last edamame July 14.
We sow our last beans 8/3,
cucumbers 8/5.
Credit Brittany Lewis
7. Succession Crop Scheduling
• A way of planning sowing
dates for even, continuous
supplies of popular summer
crops, such as beans, squash,
cucumbers, sweet corn; year
round lettuce and winter
hoophouse greens.
• As well as planning your last
sowings, you can plan a
succession of sowings all
summer.
Photo Credit: Kathryn Simmons.
For all the details, see my slideshow
Succession Planting for Continuous
Harvests on SlideShare.net
8. Suitable crops for planting and harvesting in fall
Cool weather
spring/fall crops:
• beets, carrots,
• chard, spinach,
• lettuce, salad mix,
• Asian greens, cauliflower,
• turnips, rutabagas,
• cabbage, broccoli,
• kale, collards, kohlrabi,
• radishes (large and small)
• scallions
Spinach and peas. Credit Kathryn Simmons
9. Cool weather fall crops
With fall crops, even a difference of 2 days in sowing
dates can make a difference of 2-3 weeks in harvest
date, because plants grow slower as days get shorter
and cooler.
The “Days to maturity” listed in catalogs is usually for
spring conditions. Plants may mature faster in warm
fall soils or slower once the weather cools.
Danvers 126 carrots.
Credit Kathryn Simmons
10.
11. Example calculation: Early White
Vienna Kohlrabi
58 days from sowing to
harvest.
Kohlrabi is hardy to maybe
15°F (–9.4°C). When is the
temperature likely to drop to
15°F (–9.4°C)? Not before the
beginning of November here.
We could sow kohlrabi in early
August and get a crop at the
end of October. Or mid-August
for early November.
Credit McCune Porter
12. Fast Fall Crops for when time is short
Some cool-weather crops mature in 60 days or
less. Mostly these are greens and fast-growing
root vegetables. Useful in case of crop failure.
Ready in 30–35 days:
• kale, arugula, radishes (both the very fast
small ones and the larger winter ones).
• many Asian greens: Chinese Napa cabbage,
Komatsuna, Maruba Santoh, mizuna, pak
choy, Senposai, tatsoi, Tokyo Bekana and
Yukina Savoy.
• spinach, chard, salad greens (lettuce,
endives, chicories) and winter purslane.
Ready in 35–45 days:
• corn salad, land cress, sorrel, parsley and
chervil.
Ready in 60 days:
• beets, collards, kohlrabi, turnips and small
fast cabbage (Farao or Early Jersey
Wakefield)
Tatsoi. Credit Wren Vile
13. Carrots
• Carrots prefer soil temperatures of 45°F–85°F (7°C–29°C),
• They germinate in 6 days at 80°F (27°C), their optimum.
• Keep the soil surface damp until they come through.
• We flame the beds the day before the carrots are due to emerge
(using “indicator beets”, which emerge the day before the carrots).
• We hoe between the rows as soon as we can see to do so.
• We weed and thin to 1” once the carrots are 1” tall.
We use flags to mark our progress.
• Once the carrots are salad size, we weed again and
thin to 3”
Photo credit Southern Exposure Seed Exchange
14. Scheduling fall carrots
• We sow a large planting
of fall carrots very early
in August, enough to
store and feed us all
winter. Danvers 126 is
our standard.
• In November we harvest
all of the carrots and
store in perforated
plastic bags in the walk-
in cooler.
Danvers Half-long carrots.
Credit Southern Exposure Seed Exchange
15. Beets
• Beets prefer soil temperatures of 50°F–85°F
(10°C–29°C)
• Only 3.5 days to emerge at 86°F (30°C), but
14.6 days at 50°F (10°C).
• If you can maintain a soil temperature below
86°F in late summer, you only have to do it
for a few days. Look for a forecast cooler
spell or generous rainfall.
• Hand-sowing pre-sprouted seed is an option
if the season is relentlessly hot.
• Sow 1/2″-1″ deep, tamp the soil, and keep
the surface damp with daily watering until
they emerge.
• If you want to flame-weed, use radishes as
an indicator – they germinate 1-2 days faster
than beets.
Crosby Egyptian Beet. Credit Southern Exposure Seed Exchange
16. Scheduling fall beets
• For fall fresh eating and winter storage crops, we
sow beets on 8/1 or so, dry or soaked for 1-2 hours
in a little water. (Don’t soak too long, or in a lot of
water – beet seeds are easy to drown.)
• We usually sow pre-soaked by hand. Sometimes dry
with the EarthWay chard plate 2 passes.
• We have 8/20 down as the last date - I think we
have done them later.
• Harvested 9/20- 11/15 and
stored in the walk-in cooler
in perforated plastic bags,
for winter.
Photo Detroit Dark Red Beet.
Credit Southern Exposure Seed Exchange
17. Spinach and chard
• Spinach is a challenging crop to start in hot weather!
• Optimum germination temperature 70°F (21°C) Max
85°F (29°C). Wait for soil temperature to drop (dead
nettle, chickweed, henbit germinating).
• For earlier planting, pre-sprout seeds one week. We
sow sprouted spinach 9/1 or so.
• Swiss chard germinates best at 85°F (29°C), so
consider that as a substitute for a first sowing if the
fall is impossibly hot.
Tyee spinach. Credit Kathryn Simmons
18. Scheduling fall spinach
• Fall sowing dates are
quite exacting: Sept 20 is
the latest we can sow
spinach for harvesting
October–early April, and
Sept 20–30 sowings will
not get big enough to
harvest until late
February.
• Winter Bloomsdale spinach. Credit Southern
Exposure Seed Exchange
19. Lettuce
Heat-tolerant varieties also tolerate cold.
There are also specialized cold-hardy varieties that do not tolerate
heat (because they have a relatively low water content). Sow these
in fall and winter only.
Rowcover will provide a temperature gain of 4–6 F degrees (2.2–3.3
C degrees), depending on the thickness.
Lettuce may survive an occasional dip to 10°F (–12°C) with good
rowcover — but not 8°F (–13°C), I can tell you!
Adolescent lettuce are more cold-hardy than full-sized plants.
20. Scheduling lettuce in summer & fall
The short version: sow heat-resistant
varieties (which are also cold-resistant)
• every 6-7 days in June and July,
• every 5 days in early August;
• switch to cold-hardy varieties, sow
every 3 days in late August.
• every other day until Sept 21.
• every 3 days until the end of
September (for harvests through the
winter).
Cold-hardy (not heat-tolerant) Tango lettuce. Kathryn Simmons
Cherokee Lettuce
Credit Johnnys Seeds
21. Lettuce varieties for fall and winter
Particularly cold-hardy for outdoors:
Brune d’Hiver
Cocarde
Esmeralda
Galactic
Green Forest
Hyper Red Wave
Kalura
Lollo Rossa
North Pole
Outredgeous
Rossimo
Rouge d’Hiver
Sunfire
Tango
Vulcan
Winter Marvel
Rouge d’Hiver Lettuce
Credit Southern Exposure Seed Exchange
The Salad Bowls are not so good outdoors
in cold weather but do well under cover.
Icebergs do not survive frost.
22. Brassica Surprise!
Scarlet Ohno Revival Turnip
Credit Southern Exposure Seed Exchange
Most brassicas will
germinate faster at 86°F
(30°C) than at 77°F (25°C),
provided the soil is damp.
Turnips can be up the next
day, even at 95°F (35°C).
Winter radishes and daikon
have no trouble germinating
at high temperatures.
But don’t expect much from
the cabbage, broccoli,
collards or cauliflower above
86°F (30°C).
23. Rutabagas and Turnips
Rutabagas can be stored in the
ground (unlike turnips, except in
warm climates). Mulch over them
with loose straw once the
temperatures descend near 20°F (–
7°C).
Turnips do very well in the winter
hoophouse. We also grow Purple
Top White Globe outdoors in spring
and fall.
White Egg turnip.
Credit Southern Exposure Seed Exchange
24. Broccoli, cabbage, kale
and collards in fall
Direct sowing, in drills or in “stations”
(groups of several seeds sown at the
final crop spacing), is possible, if you
have good irrigation.
If you use flats, it can help to have them
outside on benches, above the height of
flea beetles.
We use an outdoor “nursery” seedbed
and bare root transplants, because this
suits us best. The nursery bed is near our
daily work area, so we’ll pass by and
water it. Having the seedlings directly in
the soil “drought-proofs” them to some
extent; they can form deep roots and
don’t dry out so fast.
Cabbage plant. Credit Kathryn Simmons
25. Scheduling fall outdoor brassicas
We start sowing our fall
brassicas for outdoor
planting around June 26
and repeat a week later
for insurance (July 3).
Last date for sowing these
crops is about 3 months
before the first fall frost
date. In our case that
means July 14–20.
Senposai. Credit Kathryn Simmons
26. Brassica transplanting
We aim to transplant leafy
brassicas at four true leaves
(3-4 weeks after sowing).
In hot weather transplant
crops at a younger age than
you would in spring - larger
plants can wilt from high
transpiration losses.
If we find ourselves
transplanting older plants, we
remove a couple of the older
leaves to reduce these losses.
Morris Heading Collards.
Credit Kathryn Simmons
27. Kale: direct sown/transplanted mix
Our mixed direct-sow/transplant
method allows for patchy
germination, and requires less
watering than if direct sowing it all.
Three times, (8/4, 8/10, 8/16), we
sow two beds with rows 10" (25 cm)
apart and then carefully thin them,
leaving one plant every foot (30 cm)
We use the carefully dug thinnings
from those beds to fill gaps and to
plant other beds, at the same plant
spacing.
Another reason we use this system is
that we want a lot of kale, and there
isn’t time to transplant it all.
Vates kale. Credit Kathryn Simmons
28. Fall brassica harvests
• Cabbage Sept 25 - late November.
• Main broccoli harvest period is Sept 10 - Oct 15.
Smaller amounts picked either side of those dates.
• Cauliflower heads need to be harvested before they
get frosted. We use gaudy plastic clothes pins (easy to
find) to clip the leaves over a developing curd once
frosts threaten. The leaves are frost-hardy.
• Kale and collards are harvested (by snapping off the
bigger leaves) all winter in small amounts, and then in
larger amounts as spring warms up, until the end of
May, when they bolt.
• Kohlrabi from Oct 20 - Nov 15. It stores well in
perforated plastic bags in a walk-in cooler. In a plentiful
year we have eaten stored kohlrabi all winter into early
spring.
29. Asian Greens
• A quick way to fill out your
market booth or CSA bags
• A catch crop for spaces where
other crops have failed or
otherwise finished early.
• Easier to germinate in hot
weather than lettuce.
• Faster growing than lettuce
• Some of the faster-growing
types are ready for transplanting
2 weeks after sowing (or you
can direct sow them)
• Keep a flat of seedlings ready,
pop plugs into empty spaces as
they occur.
Ruby Streaks
and mizuna.
Credit Ethan Hirsh
For more details, see
my slidehow Producing
Asian Greens on
SlideShare.net
30. Cold-hardy Asian Greens
Tatsoi/tah tsoi
• small, flat rosette of shiny, dark
green spoon-shaped leaves and
white stems.
• Mild flavor, attractive appearance,
easy to grow.
• extremely cold tolerant, hardy to
22°F (–6°C) or colder.
• Can direct sow and thin into salad
mixes, leaving some to mature at
10" (25 cm) across for cooking
greens.
• Can transplant at 6" (15 cm).
• Kitazawa Seeds have a Red Violet
tatsoi, with an upright habit.
• Takes 21 days to become baby
salads;
• 45 days to reach cooking size;
Yukina Savoy
• like a bigger tatsoi, with blistered
dark green leaves, greener stems and
delicious flavor,
• about 12“ (30 cm) tall.
• Both heat and cold tolerant.
• Can transplant at 12" (30 cm).
• Needs 21 days to reach baby size, 45
days to full size;
Tatsoi, Yukina Savoy,
Credit Ethan Hirsh
32. More Cold-hardy Asian Greens
Komatsuna - also known as mustard
spinach and Summer Fest. Green or red, a
large cold-tolerant plant 18" (45 cm) tall.
Individual leaves can be picked and
bunched, or the whole plant can be
harvested. The flavor is much milder than
the English name suggests. Baby salad
size in 21 days, full size in 35 days;
Senposai is quite heat and cold tolerant, a
big plant with large, round, mid-green
leaves. Usually harvested leaf-by-leaf. It
can be very productive. Transplant it at
12"–18" (30–45 cm) spacing. Cooks
quickly (much quicker than collards), and
has a delicious sweet cabbagey flavor and
tender texture. It is a cross between
komatsuna and regular cabbage. It takes
only 40 days to mature.
Senposai. Photo Ethan Hirsh
33. Senposai in November –
the young hoophouse crop is almost ready to
take over from the well-used outdoor crop.
34. Suitable crops for planting in fall
Cold-hardy crops to
plant in fall and
harvest in winter:
• spinach
• kale
• collards
• cabbage
• lettuce
• carrots
We grow our winter-harvest
crops in our raised bed area,
which is more accessible in
winter and more suited to
small quantities.
Deadon cabbage. Credit Johnny’s Seeds
35. Choosing cold-hardy crops
Use the Winter-kill temperature chart of winter-
hardy vegetables for crops that will survive your
lowest temperatures, taking any crop protection
into account.
Add some wind protection, if you can.
Look for the hardiest varieties. At our Zone 7
farm, we overwinter Vates kale without rowcover,
but not Winterbor or Russian kales.
For details, see my slide show
Cold-Hardy Winter Vegetables
on SlideShare.net
36. Favorite hardy winter-harvest crops –
kale and spinach
We grow about 2800 row feet of
overwinter Vates kale for 100 people
and plant another 1000 feet in spring.
We grow similar amounts of Tyee spinach.
We use double hoops and rowcovers and
pick spinach throughout the winter,
whenever leaves are big enough. We pick
one bed each day in October, November,
February and March, when the weather
is not too awful. Spinach makes some growth whenever the
temperature is above about 40°F (5°C), so we
can also make occasional harvests in
December and January.
Vates kale Credit Kathryn Simmons
37. More winter-harvest crops
As well as kale and spinach,
collards, leeks and parsnips
also survive outdoors without
rowcover at our farm (Zone
7).
We grow only a few hundred
feet of collards.
Leeks and parsnips are slow
growing, start them in spring.
Lettuce can be grown
outdoors with thick rowcover
on hoops.
We have also sometimes
overwintered Danvers carrots
and Deadon cabbage.
Overwintered Vates kale
38. Winter-harvest leeks
Unlike onions, leeks grow
independently of day length
and will stand in the field at
temperatures below what many
other vegetables can handle,
increasing in size until you
harvest them.
Overwintered leeks.
Leek varieties - two main types:
• the less hardy, faster-growing
varieties, often with lighter
green leaves, which are not
winter-hardy north of Zone 8,
• the blue-green hardier winter
leeks. We like Tadorna (100
days), Jaune du Poiteau, King
Sieg (84 days, a cross between
King Richard and the winter-
hardy Siegfried, from Fedco)
and Bleu de Solaize (105 days,
very hardy).
• Giant Musselburgh (105 days) is
bolt-resistant, for overwintering
in milder climates.
39. Other hardy winter-harvest crops
• Small greens such as arugula, parsley, Belle Isle upland cress, winter
purslane, salad burnet and mache (corn salad) are very winter-hardy.
• Some Asian greens are hardy - Green in Snow mustard (Shi-Li-Hon) is the
hardiest Asian green.
• Some unusual crops like horseradish, Jerusalem artichokes, salsify, and
some endive are hardy.
• Walla Walla bulb onions and Evergreen Winter Hardy White or White Lisbon
scallions are surprisingly hardy.
• Swiss chard is hardy to 15°F (–10°C) without rowcover. To keep chard
overwinter, either use hoops and rowcover (in mild areas, Zone 6 or
warmer), or else cut off the leaves in early
winter and mulch heavily right over the
plants.
• Bright Lights chard. Credit Wren Vile
For details, see my slide show
Cold-Hardy Winter Vegetables
on SlideShare.net
40. Suitable crops for planting in fall
Overwinter crops for
spring harvest
• spinach
• kale, collards, cabbage
• lettuce, chard
• carrots
• chicories such as radicchio and
Sugarloaf,
• scallions, potato onions
• garlic, garlic scallions.
• In mild areas, peas can be fall sown
for a spring crop.
Sow 1" (2.5 cm) apart to
allow for extra losses.
Planting garlic. Credit Brittany Lewis
For details, see my Growing Great
Garlic slideshow on SlideShare.net
41. Scheduling overwinter crops for
spring harvest
We sow one or two beds of spinach from 9/20-9/30,
overwinter them as adolescents and harvest in the
spring. These plants bolt later than the ones we harvest
leaves from all winter, and earlier than spring-sown beds,
so we get a continuous supply.
With alliums, such as bulb onions, multiplier onions and
garlic, the harvest dates are regulated by day length, so
the harvest cannot be earlier, but the bulbs will be bigger
if you can overwinter the small plants.
Garlic scallions are a great early spring crop –
easy, flavorful, unusual.
42. Garlic Scallions
Small whole garlic plants. An attractive early crop
• Save small cloves from planting your main crop
• Plant close together in furrows, dropping them
almost end to end, as they fall. Close the furrow
and mulch over the top with spoiled hay or straw
• Plant next to your main garlic patch, or in a part
of the garden that's easily accessible in spring.
• We harvest garlic scallions from early March till
May, at about 7-8" (18-20 cm) tall,
• Trim the roots, rinse, bundle, set in a small
bucket with a little water, and you're done!
• Scallions can be sold in small bunches of 3-6.
• Some people cut the greens at 10" (25 cm) tall,
and bunch them, allowing cuts to be made every
2-3 weeks. We prefer to simply pull the whole
plant. The leaves keep in better condition if still
attached to the clove. Photo Kathryn Simmons
43. When to plant garlic
• Fall-planting is best. Garlic emerges quickly in the fall
• 9 am soil temperature 50°F (10°C) at 4” (10 cm) deep. We plant
in early November. If the fall is unusually warm, wait a week.
• Roots grow whenever the ground is not frozen
• Tops grow whenever the temperature is above 40°F (4.5°C).
44. Garlic in winter
If planted too late, there won’t be enough root growth
before winter, and you’ll get a lower survival rate and
smaller bulbs.
If planted too early, too much tender top growth
happens before winter.
Get enough top growth in fall so garlic has a roaring start
in the spring, but not so much that the leaves cannot
endure the winter.
If garlic gets frozen back to the ground in the winter, it
can re-grow, and be fine. If it dies back twice in the
winter, the yield will be lower than it might have been if
you had been luckier with the weather.
When properly planted, garlic can withstand winter lows
of -30°F (-35°C).
45. Multiplier Onions
• Multiplier Onions, such as Potato Onions, are similar in
needs to Garlic.
• Fall planting (Sept-Nov) produces the best yields
• They can be planted in very early Spring, if needed
Yellow Potato Onions, Credit Southern Exposure Seed Exchange (left), Kathryn Simmons (right)
46. Suitable crops for planting in fall
Hoophouse crops:
• Salad crops,
• cooking greens
• turnips,
• radishes
• scallions
• bare root transplants
for setting outdoors in
February and March
Michihili cabbage.
Credit Southern Exposure Seed Exchange
See my slideshow
Hoophouse in
Fall and Winter
on SlideShare.net
47. Hoophouses for winter crops
• Rate of growth is much faster inside
• Crop quality, especially leafy greens, is superb.
• In the hoophouse, it can be 7F warmer than outside.
• Plants can tolerate temperatures 14 F degrees lower than they can
outdoors; they recover in the pleasant daytime conditions.
• With thick rowcover (1.25oz) in the hoophouse, plants survive 21F
colder than they can outside.
• Working in winter inside a hoophouse is much more pleasant than
dealing with frozen rowcovers outdoors.
• Greenhouses & coldframes are useful, but get a hoophouse if you can.
At a hoophouse temperature of10.4°F
without rowcover, -2.2°F with,
survivors included Lettuce, Mizuna,
Turnips, Russian kales, Senposai, Tyee
spinach, Tatsoi, Yukina Savoy.
48. Fall Hoophouse Planting - September
Early September : We sow
sprouted spinach seed,
radishes, scallions, Bulls Blood
beet greens and tatsoi.
Sept 15 and Sept 24: We make
outdoor sowings of crops to
later transplant into the
hoophouse.
At the end of September we
transplant Tokyo Bekana and
Maruba Santoh at 2 weeks old,
Chinese cabbage, pak choy and
Yukina Savoy at 3 weeks.
Photo November hoophouse beds.
Ethan Hirsh
49. Fall outdoor sowings to transplant inside
• Sept 15: ten varieties of hardy leaf lettuce and romaines,
pak choy, Chinese cabbage, Yukina Savoy, Tokyo Bekana,
Maruba Santoh, chard.
• Sept 24: Red and White Russian kales, another ten
varieties of lettuce, Senposai, more Yukina Savoy, mizuna
and arugula.
• We use hoops and ProtekNet, and water frequently.
Senposai. Credit Kathryn Simmons
50. Fall Hoophouse Planting - October
Oct 15 we sow turnips. We like
Red Round, Hakurei and also
Oasis and White Egg.
Our neighbor Gary Scott sows
beet plugs in mid Oct,
transplants them in the
hoophouse and harvests from
mid-March. Ace in 72 plug trays.
In Late October we sow more
filler greens, baby lettuce mix,
spinach, turnips, chard and
radishes.
At the end of October, we
transplant Senposai, mizuna, the
2nd lettuce, kale, arugula and
Yukina Savoy at 4 weeks old.
Mizuna Photo credit Ethan Hirsh
Early October, we sow
more radishes and some
“filler” greens, (spinach,
lettuce and Asian greens).
By mid-October we
transplant lettuce at 10" (25
cm) apart, and chard.
51. Hoophouse Planting –
November and December
Nov 10-20 - more turnips, mizuna and
arugula, filler lettuce and spinach,
scallions, tatsoi, radishes and our first
bulb onions for field transplanting as
early as possible in the new year.
From mid-Nov we aim to keep a fully
planted hoophouse, and as each crop is
harvested, we immediately replace it
with another.
During December we use the “Filler”
greens plants to replace casualties and
heads of Chinese cabbage, Pak choy,
Yukina Savoy each day as soon as we’ve
harvested them.
Pak Choy replacing Yukina Savoy here.
Credit Ethan Hirsh
52.
53. Persephone days and
scheduling winter
hoophouse crops
• When the daylight is shorter than 10 hours a day not much
growth happens. It depends on your latitude.
• In Central Virginia, latitude 38° North, this lasts 2 months, from
November 21 to January 21. Soil temperature also matters.
December 15-February 15 is the slowest growing time for us.
• To harvest in the darkest days of winter you’ll need to plan a
good supply of mature crops to take you through. What has
already grown before this period will provide most of your
harvests.
• For most of the winter, our hoophouse plants are actively
growing, not merely being stored for harvest (as happens in
colder climate zones and outdoors), so we can continue sowing
new hoophouse crops even in December.
54. Winter succession crops in the
hoophouse
To maintain continuous supplies of salad and cooking
greens, as well as radishes and small turnips, we plan
several winter successions of hoophouse crops.
55.
56. Daily hoophouse tasks in winter
• Two hours work each day in winter in our 96’ x 30’ tunnel.
• Keep the temperature in the 65°F–80°F (18°C–27°C) range during the day, opening
the big high windows, and the doors as needed. If the sun is shining we usually open
the windows around 9 am and close them around 2:30 pm (a few hours before dark)
to store some of the warmth.
• Even in cold weather, plants need fresh air! High-density cropping can really use up
the carbon dioxide in a closed hoophouse very quickly. When this happens,
photosynthesis crashes and plant growth becomes limited. Soil high in organic
matter contains high levels of organisms that produce carbon dioxide. Dense plant
canopies can trap this near soil level, where it is most useful.
• Our main task each day is harvesting. In the winter of 2009–2010, we had frozen soil
or snow on the ground outside for a month (very unusual for us). Despite this we
were able to keep a hundred people in fresh salad and cooking greens (with turnips
and scallions for variety) for the whole month.
• Aside from harvesting, jobs include planting new crops, clearing old ones, spreading
compost, hoeing, hand weeding and supplying water as needed.
• We have drip irrigation. In the middle of winter, not much water is needed, and we
try to only water when a relatively mild night is forecast.
57. Nitrate accumulation
• During periods of short daylight length, there is a health risk
associated with nitrate accumulation in leafy greens. Nitrates are
converted in the body into toxic nitrites, which reduce the blood’s
capacity to carry oxygen. Also, nitrites can form carcinogenic
nitrosamines.
• Plants make nitrates during the night, and convert them into leaf
material during the day. It takes about six hours of sunlight to use up
a night’s worth of nitrates. In winter, a small handful of leafy
vegetables can exceed the acceptable daily intake level of nitrate for
an adult, unless special efforts have been made to reduce the levels.
• Spinach, mustard greens and collards contain about twice as much
as lettuce; radishes, kale and beets often have two and a half times
as much. Turnip greens are especially high, at 3 times lettuce levels.
58. To keep nitrate levels as low as possible:
Grow varieties best suited for winter;
Avoid animal-based fertilizers; use organic compost.
Ensure soil has sufficient P, K, Mg and Mo
Water enough but not excessively;
Provide fresh air as soon as temperatures reach 68°F (20°C), so that
carbon dioxide levels are high enough;
Harvest after at least four (preferably six) hours of bright sunlight in
winter;
Avoid harvesting on very overcast days;
Avoid over-mature crops and discard the outer leaves. Harvest
crops a little under-mature, rather than over-mature;
Refrigerate immediately after harvest, store harvested greens at
temperatures close to freezing;
Use crops soon after harvest;
Mix your salads; don’t just eat spinach.
59. Scheduling for a continuous and
timely supply:
At Twin Oaks, to keep us on track, we use
A descriptive month-by-month Garden Calendar,
on my blog www.sustainablemarketfarming.com at the
beginning of each month since July 2012.
Maps of the layout of the crops in the various
gardens
A Field Planting Schedule
A Seedling Schedule for our greenhouse
production of transplants.
A Hoophouse Planting Schedule
A pocket notebook
60. Field Planting Schedule
Draw up your list of outdoor planting dates, along with
varieties, row feet, spacing, notes and space to write
down what you actually do.
62. Meeting seasonal challenges:
Dealing with the challenges of hot weather
Choose appropriate crops and varieties. Read catalog
descriptions carefully. Look for flavor, productivity, disease
resistance and cold-hardiness. Swiss chard will germinate in
warmer soils than spinach.
Consider direct-seeding crops rather than transplants. They can
be more cold-tolerant, probably because there’s no damage to
the taproot.
Plant seeds deeper than you would in spring, as the soil is
already warm and you don’t want seeds to dry out.
In dry conditions sow in
sunken furrows.
63. Sowing when soils are hot
1. Consult tables in Nancy Bubel’s New Seed Starter’s Handbook or
Knott’s Vegetable Grower’s Handbook, on the germination
requirements for your crop, and the expected time to emergence
under your field conditions – and use a soil thermometer.
2. If soil temperatures are too high for good germination, cool a
small part of the outdoors:
– Shade from other plants, shadecloth, boards, burlap bags,
– For crops you normally direct seed, consider cooling a small
nursery bed for your seedlings and transplanting later.
3. If outdoors is impossible, start seeds indoors:
– Put a plastic flat of lettuce in your refrigerator or a cool room.
– Use plug flats or soil blocks rather than open flats, to reduce
transplant shock.
64. Water
Getting enough water to the seed and maintaining that
level can be tricky in hot weather
• Pre-water furrows for large-seeded crops.
• After sowing, watering should be shallow and frequent.
• For close-planted small seeded crops, use overhead
sprinklers.
• Drip irrigation is a help for direct seeded crops,
although it can be hard to get even watering all along
the row unless the emitters are closely spaced.
• Chilled water, night watering, and even ice on top of
the rows can help reduce soil temperatures as well as
supplying vital moisture.
65. Protection from pests
For summer nursery seedbeds we use
rowcover or ProtekNet (from Purple
Mountain Organics) on wire hoops.
Overly thick rowcover or rowcover
resting directly on the plants can
make the seedlings more likely to die
of fungal diseases in hot weather —
good airflow is vital.
For transplanted crops, an 84" (2.1 m)
width rowcover or mesh can form a
tunnel over two crop rows 34” apart,
giving good airflow.
Photo credit Dubois Engineering
66. Dealing with the challenges of cold weather -
Extending the survival of frost-tender crops beyond the
first fall frosts
The first frosts may be very slight, and will often be followed
by a few more weeks of warm weather. So it can be worth
protecting susceptible crops. (Unless you’ve reached the
exhaustion point we call “Praying for a Killing Frost.”)
When planning late crops, look for nooks with a warmer
microclimate. Avoid frost pockets.
Seaweed foliar sprays used a few days ahead of expected
frosts will toughen up cell walls and reduce frost damage.
Some growers take down the stakes or cages of tall plants
like tomatoes, lay the plants down on the ground and cover.
Prepare a Frost Alert Card.
67. Frost Alert Card
• Harvest all ripe tomatoes, eggplant, corn, limas,
cowpeas, okra, melons.
• Harvest peppers facing the open sky, regardless of color.
(Often only the top of the plant will get damaged by
frost).
• Harvest or cover lettuce, zucchini, summer squash,
cucumbers, beans, Chinese cabbage, pak choy and celery
that won’t be covered.
• Check winter squash and harvest any very exposed
squash.
• Set up sprinklers for the night, on tomatoes, peppers and
a cluster of beds with high value crops.
68. Sprinkler irrigation kept these tomatoes alive!
Overhead irrigation can protect crops from early frosts in fall (or late frosts in spring).
Sprinklers turned on just before frost started kept these plants warm enough to
survive– as long as new ice kept forming on the plants. Once the sun came up and
temperature rose above 32°F again, the sprinklers were turned off, the plants thawed
out and were still alive. This method works because water gives off heat to the plants
as it freezes into ice, and the formation of an ice shell around the plant prevents the
colder air reaching the plants.
Credit Southern Exposure Seed Exchange
69. Rowcover
Lightweight, easy to use, easy to store. Edges
need to be held down by bags of rocks or sand,
plastic jugs of water, or metal or wooden stakes
lying along the edges.
To protect against frost, you need a heavyweight
rowcover. Dupont Xavan 5131 (previously called
Typar). 1.25 oz/sq yd) fabric, can last for more
than six years. Spunbonded polypropylene with
UV stabilizers, 75% light transmission, and
provides 6 F degrees (3.3 C degrees) of frost
protection.
Thinner types are for protection from insects. We
use Agribon 17 (or 19), spun-bonded
polypropylene 0.55 oz/sq yd, transmits 85% of
sunlight, and offers 4 F degrees(2.2 C degrees) of
frost protection.
Thinner rowcover can be used doubled up in
severely cold weather, if you don’t have enough
thick rowcover.
Photo credit Kathryn Simmons
70. Avoiding pitfalls of rowcover
If you are growing on bare soil
rather than plastic mulch, weeds
will grow very well, secretly and out
of sight.
Rowcover reduces light levels.
Ventilate covered crops in mild
weather, so they don’t lose their
cold tolerance.
Hoops keep rowcover from sticking
to frozen leaves and reduce
abrasion. In winter we use double
wire hoops — the outer hoops trap
the rowcover so it doesn’t blow
away. 9- or 10-gauge wire. The
microclimate under hooped
rowcovers is very pleasant in chilly,
windy weather.
There are also spring steel hoops,
for setting by machine or by hand.
o Easy to store - they return to a
relaxed bow shape when removed
from the soil, don’t get tangled.
o Just one length, 64" (1.63 m),
which is fine for a single row of
plants, but less good for our 48"
(1.2 m) beds with multiple rows.
71. DIY weather-forecasting
Learn your local weather patterns by keeping records and watching
what happens.
• Our mid-Atlantic climate is controlled by three weather systems,
mainly by moisture from
– the Gulf of Mexico,
– the Bermuda High Pressure area in summer,
– the recurrent waves of cold Canadian air in winter.
• Rain (fairly evenly distributed throughout the year in our county)
– has slight peaks in January, February and March
– and again in early June and August.
• Some parts of our area can experience long periods of drought.
– September-November is the drier season but it’s also the hurricane
season, so the net result is very variable.
• We use Wunderground, but subtract 5F° from their forecast night
lows for our nearest town, and mentally downgrade the chance of
rain by 10%, as rain often passes us by as it scoots along the river
valley north of us.
72. Predicting frost
Frost is more likely at Twin Oaks if:
• The date is after 10/14 or before 4/30.
• The Wunderground forecast low for Louisa Northside is 37°F (3°C) or less.
• The daytime high temperature was less than 70°F (21°C).
• The temperature at sunset is less than 50°F (10°C).
• The sky is clear.
• The soil is dry and cool.
• The moon is full or new.
• There is little or no breeze, although if temperatures are falling fast, the
wind is from NW and the sky is clear, then polar air may be moving in, and
we'll get a hard freeze.
• The dew point forecast is low, close to freezing. Frost is unlikely if the dew
point is 43°F or more.
73. Resources - General
ATTRA attra.ncat.org
Market Farming: A Start-up Guide,
Scheduling Vegetable Plantings for a Continuous Harvest
Season Extension Techniques for Market Farmers
Intercropping Principles and Production Practices
Plugs and Transplant Production for Organic Systems
SARE at sare.org -A searchable database of research findings
SARE’s Season Extension Topic Room
SARE Crop Rotations on Organic Farms, A Planning Manual, Charles Mohler and Sue Ellen
Johnson, editors.
extension.org/organic_production The organic agriculture community with
eXtension. Publications, webinars, videos, trainings and support. An
expanding, accessible source of reliable information.
Growing Small Farms: growingsmallfarms.ces.ncsu.edu/ Farmer Resources,
Farm Planning and Recordkeeping to download Joel Gruver’s spreadsheets.
Purple Mountain Organics, Tacoma Park, MD. Tools and supplies (ProtekNet)
http://www.purpletools.net/protek-net-insect-pest-netting/
74. Resources - Planning
The Twin Oaks Harvest Calendar by Starting Date and by Crop are available as
pdfs on my website sustainablemarketfarming.com/2013/11/07/growing-for-
market-articles-2/
AgSquared online planning software: agsquared.com
COG-Pro record-keeping software for Certified Organic Farms: cog-pro.com
Free open-source database crop planning software
code.google.com/p/cropplanning.
Mother Earth News interactive Vegetable Garden Planner, free for 30 days:
motherearthnews.com/garden-planner.
Target Harvest Date Calculator: (Excel spreadsheet) johnnyseeds.com/t-
InteractiveTools.aspx
Tables of likely crop yields:
johnnyseeds.com/assets/information/vegetablecharts.pdf.
Mark Cain www.drippingspringsgarden.com under the CSA tab, you can
download their Harvest Schedule. Notebook-based system.
Clif Slade’s 43560 Project: VABF newsletter
vabf.files.wordpress.com/2013/08/clif-slade-43560-demo-project.pdf.
75. Resources - slideshows
Many of my presentations are available at www.Slideshare.net. Search for Pam Dawling.
Crop Rotations
Cold-hardy Winter Vegetables
Crop Planning for Sustainable Vegetable Production
Fall Vegetable Production
Feed the Soil
Growing Great Garlic
Intensive Vegetable Production on a Small Scale
Producing Asian Greens
Production of Late Fall, Winter and Early Spring Vegetable Crops
Succession Planting for Continuous Vegetable Harvests
Sustainable Farming Practices.
Mark Cain: Planning for Your CSA: www.Slideshare.net (search for Crop Planning)
Daniel Parson: Planning the Planting of Cover Crops and Cash Crops, www.Slideshare.net
Joel B Gruver: Cover Crop Innovation www.Slideshare.net
Tom Peterson: Farm Planning for a Full Market Season Appalachian Farmers Market
Association and Appalachian Sustainable Development
http://vabf.files.wordpress.com/2013/02/tom-peterson-farm-planning-for-a-full-market-
season.pdf
Brad Burgefurd: Cultural Practices And Cultivar Selections for Commercial Vegetable Growers.
www.slideshare.net/guest6e1a8d60/vegetable-cultural-practices-and-variety-selection
76. Resources - books
The Complete Know and Grow Vegetables, J K A Bleasdale, P J Salter et al.
Knott’s Handbook for Vegetable Growers, Maynard and Hochmuth
The New Seed Starter’s Handbook, Nancy Bubel, Rodale Books
The Organic Farmer’s Business Handbook, Richard Wiswall, Chelsea Green
Sustainable Vegetable Production from Start-up to Market, Vern Grubinger,
The New Organic Grower, Eliot Coleman, Chelsea Green
Extending the Season: Six Strategies for Improving Cash Flow Year-Round on the
Market Farm a free e-book for online subscribers to Growing for Market magazine
Sharing the Harvest, Elizabeth Henderson and Robyn Van En
Gardening When it Counts, Steve Solomon
Grow a Sustainable Diet: Planning and Growing to Feed Ourselves and the Earth,
Cindy Conner, New Society Publishers, (worksheet based). DVD/CD set Develop a
Sustainable Vegetable Garden Plan
Crop Planning for Organic Vegetable Growers, Daniel Brisebois and Frédéric
Thériault (Canadian Organic Growers www.cog.ca) Includes Excel spreadsheets or
pdfs which can be downloaded blank.