3.3 based on 40 ratings

Updated on Nov 06, 2010


Life Science



Difficulty of the Project




Safety Issues


Approximate Time Required to Complete the Project

One-two months

To determine whether plants grow better in soil or in fish ponds. The purpose of this experiment is to grow lettuce plants in two different conditions to determine whether plants grow more rapidly in soil or in water. Seeds will be started in both mediums and growth will be measured daily in overall plant health and number of leaves.

  • 2 20 gallon plastic tubs
  • 10-15 feeder goldfish
  • Styrofoam
  • lettuce seeds
  • paper towels
  • fish food

Aquaculture and agriculture have been an important part of human society for many thousands of years. The pairing of these two technologies, termed aquaculture, has recently gained momentum on many island nations where land is scarce. Farmers grow a food fish, such as tilapia or catfish in symbiosis with crops. A small system comprised of a 1500 liter tank and 20 square meters of planting surface space can yield up to 15 kilograms of fish and 100 kilograms of vegetables per month. For many poor nations, where malnutrition is often a serious issue, the introduction of these systems could greatly improve health and increase life expectancy. If it can be proven that aquaponic systems significantly boost plant growth and vegetable production, farmers can be taught how to incorporate the systems into their current farming practices and world food production can increase, potentially staving off famine in many parts of the world.

  • aquaculture
  • agriculture
  • hydroponics
  • aquaponics
  • sustainability
  • organic foods
  • fertilizer
  • dissolved solids
  • nitrite cycle

  • What nutrients do plants need to thrive?
  • How do aquatic plants get the nutrients the need in the wild?
  • How does hydroponic agriculture work?
  • How are pond aquaculture systems maintained?
  • Why is sustainable agriculture important to the long-term survival humans?
  • How does the nitrite cycle affect fish?

  1. Fill one plastic tub with clean water (preferably either distilled or conditioned to remove chlorine and other harmful chemicals found in tap water).
  2. Fill the second plastic tub with potting soil or soil from the garden.
  3. Place 10-15 feeder goldfish in the tub with water. The fish will require about a week to "cycle" the water. During this time expect that 25-75% of the fish will die. While you can start your seeds as soon as you add fish to the system, there will be very few nutrients in the water until the end of the first week. It is recommended that you start your seeds after this time.
  4. Feed fish daily, following the instructions on the fish food.
  5. Bore 10 dime-sized holes two inches apart in the piece of Styrofoam.
  6. Tear the paper towel into ten strips.
  7. Sink 1/4 of a strip into the water through one of the holes. Repeat for the other paper towels in the other holes.
  8. Lay the rest of each paper-towel flat on top of the Styrofoam.
  9. The paper towels will soak up water through the submerged end and become wet.
  10. Place a lettuce seed on each towel.
  11. Plant 10 seeds 2 inches apart 1/4 inch deep in the soil and water gently with tap water.
  12. Water plants in soil daily. Do not fertilize.
  13. Measure plant growth daily, using charts such as the ones below.
  14. To determine whether plants grow more quickly in water or in soil, compare the average growth rates from each group.

stem height
Aquaponics (AP) 1
AP 2
AP 3
AP 4
AP 5
AP 6
AP 7
AP 8
AP 9
AP 10
average AP height
Traditional Soil (TS) 1
TS 2
TS 3
TS 4
TS 5
TS 6
TS 7
TS 8
TS 9
TS 10
average TS height

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