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Assembling a Larger System Assembling a Larger System From "Fresh from the Garden" episode DFFG-210

Figure A

Joe next assembles a large homemade hydroponic system (figure A) borrowed from another gardener. The system consists of six growing tubes made of 6" PVC pipe; a stand and trellis made of PVC; a nutrient tank; a pump and a manifold. The tank sits under the table, and the pump sits inside it to push nutrients up to the plants. Each growing tube has a drainpipe that leads back to the tank. The manifold sits on top of the pipes and sends pressurized water to the tubes.

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Here's an explanation of how the nutrients get to the plants in this system; this is what makes it so unique. The water is pushed through a square of PVC, the manifold, and then gets shot out to small plastic tubes that run inside each of the larger growing tubes (figure B). The nutrient tubes have very small holes in them, one hole between each plant site. The nutrients shoot out the hole and spray the plant roots. At the same time, the jet of water makes air bubbles so the plants get enough oxygen.

Joe fills the tank with water (figure C); it holds about 50 gallons. Then he adds two cups of nutrients to the tank and lets the system run for about 30 minutes to get all of the nutrients mixed in.

Figure B

Figure C

Now that the garden is running, it's time to add some plants. One of the easiest ways to plant a hydroponic garden is to use purchased seedlings, especially if you don't have time to grow the seeds yourself. The key is to choose the healthiest plants you can find and then to get all of the dirt off their roots. The best way to do this is simply to wash the roots off.

1. To wash the dirt off the roots (figure D), you should use lukewarm to cool water. Water that's too warm or too cold can send the plant into shock. Run water over the roots and gently separate them to get the dirt out (figure E). Any dirt left on the roots could clog up the tiny spray holes in the nutrient tubes.

Figure D

Figure E

2. After the roots are clean, pull as many roots as you can through the bottom of the cup (figure F) and then add pebbles to hold the plant in place and to hold it upright. The pebbles Joe is using are pieces of expanded clay (figure G); they're very hard, but they're also very light so that they don't damage the plant roots.

Figure F

Figure G

Once all of the plants are in, Joe uses plant clips and string to tie them to the upper trellis (figure H). The string will give them support to climb straight up, which is really important with a small garden like this. He ties the string loosely to the top of the trellis, attaches the clips to the base of each plant (figure I) and winds the string around the stalk.

Figure H

Figure I

This garden will stay outside on the deck for the whole season. Joe will have to check the water level daily and the pH and nutrient levels every few days. Because the pump runs full time, he won't need a timer, but he does have to make sure the tank doesn't dry out, or the pump will burn up. In a few weeks these plants will completely cover this frame (figure J). Because they have all the water and nutrients they need, they're going to grow very, very fast.

After four weeks, the plants are going crazy. With this type of hydroponic garden, you really have to stay on top of plant growth and tie or clip the plant stalks every few days. In addition to checking the plant supports, you need to look for signs of pests and diseases (figure K). One diseased plant can infect all the other ones when you have so many plants right next to each other. Remove any sick plants immediately.

Figure J

Figure K

Because plants grown hydroponically don't have to spend their energy trying to find food, they can spend more time growing. This also can make them healthier and stronger, because they can use some of that energy to fight off diseases. Since the leaves of the plants never get wet unless it rains, they're much less likely to get leaf fungus, mildew and mold.

Even though hydroponic plants are good at fighting off diseases, they still have to fight pests. Even if it's hydroponic, bugs and caterpillars can nevertheless find a way into your garden and set up right next to your house. Pick off and dispose of any bugs you see.