|MadSci Network: Botany|
For the hydroponics treatment, get a standard hydroponic nutrient solution (such as DNF) from a hydroponics supplier or make a hydroponic solution used by scientists, such as a Hoagland solution. For the aquaponics treatment, you would probably want to rely just on fish wastes to provide plant mineral nutrients. The soil treatment should be a good quality potting soil, not outdoor soil which may have diseases. You could irrigate the soil-grown plants with the same hydroponic solution or use a fertilizer designed for potting soils, such as Miracle Gro. Fertilizers such as Miracle Gro are not satisfactory as hydroponic solutions although you could determine that for yourself if you wanted to make that part of your experiment. If you are using electric lights, a bank of three, 4 foot, 2-tube fluorescent fixtures is recommended. They can be left on at least 16 hours per day to provide as much light as possible. For the same reason, the tops of the plants should be within a cm or two of the tubes. If you use Wisconsin Fast Plants, you want the lights on 24 hours per day. You may be able to let the lights on 24 hours per day for other plants although some plants, such as tomato, are harmed if the lights are on more than about 18 hours per day. Cool white tubes are preferred over the more expensive "gro-light" tubes. Probably the easiest vegetable to grow is leaf lettuce because it is short so can be kept close to the fluorescent tubes for maximum light, it does not need staking, grows rapidly, and it does not need to flower or fruit to produce its edible part. Radish is another easy and fast vegetable. For your type of experiment tap water is probably satisfactory unless it is very poor quality. Distilled or deionized water is used for hydroponic solutions when mineral nutrient deficiency experiments are run. You may need to dechlorinate the water for the sake of the fish. References Fluorescent light systems for plant growth Re: How can I conduct a hydroponic experiment? Re: Which plants are best suited for hydroponics and why"> Re: How can I build a hydroponics system for a science fair? Hershey, D.R. 1995. Plant Biology Science Projects. New York: Wiley.
Try the links in the MadSci Library for more information on Botany.