We found the available resources provided in our links, lacking in diversity. While they teach the basic principles of hydroponics they fail to explore how and why these methods might be superior. Neither do they examine the many possible experiments that explore the countless factors effecting plant growth and yield. Not to worry. We’ve been helping kids of all ages put projects together since we opened our doors and below you will find just some of the many variations that can be done with the basic templates in the links. Almost all of them can be adapted to any grade level according to the complexity of the system and curriculum. The first and most fundamental, Hydro vs Dirt, is an excellent example of how this can work.
- Hydro vs. Dirt-Take groups of seedlings, as identical as possible (cuttings from the same plant are recommended for grades 6-12 as this eliminates the genetic variable http://simplyhydro.com/cuttings.htm). Plant half in soil and half in any style of hydroponic system. Make sure all other factors; lighting, temperature, etc. are identical and have students log the differences throughout the process. Look at circumference of stalk and branches, density and color of foliage, fruit and flower yield, including differences in taste and aroma if applicable. Also examine the differences in the root systems. This concept can be simplified down to pre-K by helping students make a simple raft system for the hydro and using peat pots or plastic cups for the soil. Use lettuce (FAST & EASY) for your crop. For MG-12, have the class work together to design and build a more complex hydroponic system, http://simplyhydro.com/freesys.htm and chose a fruit or flower producing crop such as tomatoes, cucumbers or peppers.
- pH Levels-Have students examine the effects of pH levels on plant health by running three smaller systems side by side, keeping one alkaline, one acidic and one neutral. http://simplyhydro.com/ph.htm
- Nutrient Strengths-How much food do plants need? Is more better? Again, running several smaller systems side by side, do several variations and see how plants respond to everything from straight water to double nutrient mixing ratios.
- H2O Quality-Run several systems side by side using the same nutrient but varied qualities of water; spring, tap, RO, rainwater, etc.
- Hours of Light-
- Intensity of Light-
- Foliar Feeding-Test the benefits of foliar feeding using three identical hydroponics systems (the simple Floating Raft System http://simplyhydro.com/free2.htm will work fine for this) do one with nutrients in the tank only, one foliar feeding only and one combination. Document all observations.
- Wind Stress-Using different hydroponic systems or dividing the area on a larger system, test the effects of wind stress on plants by placing fans on some plants and not others. Note all differences, looking at girth and strength of stalks and stems, in particular.
- Water Temperature-Another easy peasy one that can be done with the Floating Raft System or the simple and inexpensive Bubbler Bucket System http://simplyhydro.com/free7.htm. Run one or more systems at optimal water temps and a comparative number at lower and higher temps. Observe the effects on the nutrient solution as well as the effects on the plant.
- Oxygenation of Water-Same set up as Water Temperature experiment except this time, temps are identical and students will be testing the effects of oxygen levels on plants and nutrient solution using varied numbers of air stones in the reservoirs.