MadSci Network: Environment & Ecology

Re: 'Can I, and how can I make a hydroponics system that is small?

Date: Thu Dec 3 16:33:29 1998
Posted By: Eric Biddinger, Grad Student, Horticulture, Penn State University
Area of science: Environment & Ecology
ID: 910306651.En

MadSci Network: Environment & Ecology

For more back ground on hydroponics, I suggest you look at a couple of earlier questions sent into MadSci Network. One is a general overview. The oth er has some good links.

Now, your question. Yes, you can build a small hydroponics system. In fact, you might be surprised at how easy it is and how available the materials are. I am going to illustrate two different variations. These instructions are off the top of my head. I have illistrated, written instructions burried in a file somewhere, but this will have to do for now.

Supplies you will need for the canning jar system:
1. A number of canning jars (glass is better than metal because of the possibility of metal toxicity) The size of jar you use will depend on the size of the plant you want to grow and how long you are going to grow it
2. Enough aluminum foil to entirely cover the outside of each jar
3. An air pump for a fish tank
4. Enough plastic tubing, elbows, etc. to get one air line into each jar
5. A lid and ring for each jar (and maybe a few extra, just in case)
6. Some foam plugs (2-4 cm across)
7. Hydroponic nutrient solution
8. pH test strips and adjustment solution (The same stuff used for fish tanks should work)
9. A sunny place to set up the system or additional grow lights
10. Seedlings to put in the system

1) The first thing is to get the seeds started. It is not easy to start seeds in a hydroponic system. I would suggest that you start your seeds in a starter tray or other small container. Use vermiculite or perlite as a growing medium. They will be easier to wash off of the roots than regular potting soil when the time comes to transplant the seedlings.

2) First, wrap each jar all the way to the top with foil. This will keep light away from the nutrient solution and prevent algae growth. The foil can be removed for short periods to look at the roots.

3) Next, punch two holes in each lid. The first should be 2-4 cm across (or what ever size is needed to hold the foam plugs) and centered in the lid. The second should be large enough so that the plastic tube will fit snugly.

4) Fill the jars with nutrient solution. Leave about 2 cm to the top of the jar. A concentrated solution can be purchased from mail order companies and some garden centers. Just a note, regular plant fertilizers do not contain everything the plants need to grow in hydroponics.

5) Set up the air system so that each jar has a line running through the lid and into the solution. The line should be long enough to reach the bottom of the jar. Turn on the air carefully. The air flow should be a gentile bubbling. If it looks like the solution is boiling, you will need to find some way to turn down or clamp off some of the air flow. (I think I remember seeing pressure regulators for aquarium air pumps, but I'm not sure.)

6) Remove the seedlings from the growing media and carefully rinse the media from the roots. It is important to disturb the roots as little as possible. Next, cut a slit halfway through the foam plug so that you can gently center the stem of the seedling into it. Carefully handling the plants and plugs, place them into the holes in the center of the lid. The roots should be some what submerged into the solution. It is not necessary for all of the roots to be in the solution.

7) Maintaining the system - Add nutrient solution to the jars as needed. As the plants grow, they will take more solution. Also, check the solution pH once in a while. The solution should be between 5.5 and 6.5. A complete change of solution every couple of weeks might not be a bad idea, either. This system will require daily maintenance.

The second system is just a variation of the first. Use a 10 - 20 gallon fish tank with a piece of Styrofoam board on the top instead of the jars and lids. You can put 8 to 12 plants in a single tank and the air system is much simpler to set up.

One last thing. I will caution you about the choice of carrots as the plant to grow hydroponically. For some reason, carrots don't normally form the enlarged tap root in hydroponics. Beans work really well.

I wish you luck with the experiment. If you have any questions please feel free to e-mail me. Thanks for the question!

Eric J. Biddinger
Grad Student - Department of Horticulture
Penn State University

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