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to “How would I build a small floating hydroponic system for a science experiment?”

1. IHateLaundry Says:
   July 3rd, 2008 at 4:17 pm

   I built one in high-school, it was a long time ago, but I remember cutting styrofoam squares, hollowing them so that the base of the square, the part resting in the water was still solid, but the styrofoam was more of a bowl now. I stuffed it with cotton to absorb water, and placed the seeds in the cotton. I used thin wire, like coat-hangar wire to make a six by nine rectangle, I threaded the wire through the styrofoam to make them stay in place. the entire contraption floated in a tupperware plastic rectangular container that I took from home.

   It worked really well. I guess you could put fish in there, but I don’t know how well that would work. I’m lost on the gelatin thing also.

2. dna man Says:
   July 5th, 2008 at 7:54 pm

   You may not even need to float them. A board of foam core used in house insulation (available at any hardware store) and a plastic 1 L cup can do as well. Or you can float the same assembly I am describing instead of cups. This is actually a very real way to do hydroponics on small low cost scale for research.

   Get foam board (thick 1 inch stuff is more durable), cut squares that will cover cups or large strips to float. Put a hole in center (in rows) with hole saw, hot shot glass etc, a nice round regular hole is all that is needed. Get some foam rubber plugs or strips (the sort of foam in furniture cushions) large enough to stuff in hole tightly. Get some white silicone grease or petroleum jelly (Vaseline). Get a fish air pump and stone to airate the watter or nutrient solution (this is important). Use 1 stone per tub or cup. Reduce the airflow with a clamp till its just a tiny Bubble stream, not to splash lots.

   Sow plants (say tomato seed) in pots or cells & flats with soil. let then germinate and grow till they have 4-6 leaves (about 3 weeks after germination). You want nice small plants.

   The get a hose and wash off the dirt from the small roots. Use the grease to oil up the foam plugs and make it water proof. insert the stem of a plant into each cut plug or foam strip, fold and stuff into the hole (green side up . Grease the base as need to water proof the hole-foam junction. Place in cup full up with solution and air. Change solution frequently, at least once a week, top off the cups with water daily to give back what the plants transpire. You can grow a small breed tomato to maturity in these if you use cups and a few bamboo stick if they try to fall.

   If you want to sow seed directly into the system, sow on tight packed cotton plugs or rock wool plugs (spun stone wool). When the plants get big you can re-pack them in greased foam plugs. The cotton will rot and mold so greased plugs or stone wool is better.

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