A simple, repeatable experiment done by a third grader in Oakland, CA.

1. The Impact of Detergent
How does laundry detergent
affect the growth of plants?

2. Hypothesis
• I think when a plant is
watered with water that has
laundry detergent in it; the
plant’s growth will be
negatively affected.
• I think all the plants watered
with laundry detergent and
water will die, no matter what
type of detergent it is.

3. Procedure
• I am planting three pots of violets. I will water
one plant with plain water, one plant with a
mixture of water & Tide detergent and one plant
with a mixture of Trader Joe’s Chemical Free
Laundry Detergent and water.
• Plant violets in three different pots
– Make detergent mixtures – I used 1 cup of soap to 7 cups of water
• Set up plants in a sunny location
– Water each plant with different water. One with a mixture of
Tide, one with a mixture of Chemical Free detergent and one with plain
water
– Water the same plants with the same water mixture when needed –
probably every other day
– Take notes every day about the plants: How do they look? Did they
grow? Is the soil dry?

4. List of Materials:
• 6 violet plants
• 3 pots
• 1 bag of soil
• 1 watering can for plain water
• 2 milk jugs to hold the detergent-water mixtures
• Tide detergent
• Trader Joe’s Chemical Free Detergent
• Water
• Sun
• Journal & Pencil
• Cards to label plants for photographs
• Camera

5. Day 1 Photos
This is the pot that
used plain water with This is the pot that
This is the pot that
no additional used a chemical free
used a mixture of Tide
detergents detergent from Trader
and water (Tide Water)
Joes (TJ Water)

6. Results
• Day One: I planted the violets in three different pots and water each one with a different water mixture.
– Tide plant: 9cm tall, healthy green leaves and bright yellow flowers. Soil moist.
– Chemical Free detergent plant: 10 cm tall, healthy green leaves and bright yellow flowers. Soil moist.
– Plain water plant: 9 cm tall, healthy green leaves and bright yellow flowers. Soil moist.
• Day Two: No change and I did not water the plants because the soil was moist.
• Day Three: I watered all three plants because soil was dry.
– Tide plant: 7cm tall, plant is sagging; leaves are green and bright yellow flowers. Soil moist after watering.
– Chemical Free detergent plant: 10 cm tall, healthy green leaves and bright yellow flowers. Soil moist after
watering.
– Plain water plant: 10 cm tall, healthy green leaves and bright yellow flowers. Soil moist after watering.
• Day Four: I did not water this day.
– Tide plant: 4cm tall, plant is dying; leaves are brown and the flowers look dry and shriveled up. Soil moist.
– Chemical Free detergent plant: 11 cm tall, healthy green leaves and bright yellow flowers. Soil moist.
– Plain water plant: 11 1/2 cm tall, healthy green leaves and bright yellow flowers. Soil moist.
• Day Five: I watered all three plants because soil was dry.
– Tide plant: 1cm tall, plant is dead; leaves are really brown and dry the flowers look dry and shriveled up. Soil
moist after watering.
– Chemical Free detergent plant: 12 cm tall, healthy green leaves and bright yellow flowers. Soil moist after
watering.
– Plain water plant: 12 cm tall, healthy green leaves and bright yellow flowers. Soil moist after watering.

7. The impact After 4 days
This is the pot that
used plain water with This is the pot that
This is the pot that
no additional used a chemical free
used a mixture of Tide
detergents detergent from Trader
and water (Tide Water)
Joes (TJ Water)

8. Findings
• I found out that some detergents effect plant
growth.
• Tide has ingredients harmful to plants that Trader
Joes Chemical Free detergent does not.
• I was surprised by how quickly the Tide watered plant
died.
• My observations tell me that the Chemical Free
detergent might be slowing the plant growth
down, but I would need to run my experiment longer
to be sure. The difference in plant growth is small;
the difference would become greater over time if the
Chemical Free detergent were slowing the plant
growth.

9. Growth Chart

10. Conclusions
• The Tide detergent has something in it that is bad for
plants. The Chemical Free detergent didn’t have the same
effect on the plant.
• My hypothesis was not entirely correct because not all
laundry detergents will kill plants.
• I learned that it is important which laundry detergent we buy
and use since the chemicals in the detergent can be very
harmful to plants and probably other living things.
• Further Research:
– My mom and I did more research and we learned that many
laundry detergents have petroleum products in them. These are
the chemicals that probably killed my plant and are known to
hurt fish. I also learned that it is really hard to get all of these
petroleum chemicals out of the water when it is at the water
treatment plant.

11. Additional Links
• http://www.copperwiki.org/index.php/G
reen_laundry_detergent
• http://www.grist.org/article/its-a-
wash/
• http://www.thegreenguide.com/greengui
de/home-garden/cleaning/laundry-
detergents