Tomato PVC DWC

I transplanted the plants from my cloner into an experimental tank which employs a hydroponic method called "Deep Water Culture" (DWC).  The roots are continuously immersed in the hydroponic nutrient solution.  What keeps the roots from drowning is the continual aeration of the nutrients using air stones.  The tank below is made of 4 inch PVC sewer pipe.  It is U-shaped and 10 feet long -- 20 feet total.  It holds 10 gallons of nutrients aerated with only two small airstones spaced 10 feet apart.  As the roots grow and fill the pipe it will be important that each plant have plenty of air-rich nutrients, so instead of using lots of air stones to make sure the nutrients are evenly aerated and distributed I put a small water pump at one end of the tank which then transfers nutrients to the other end of the tank.  The nutrients are continuously flowing at 60 gallons per hour through the tank.  Since this is October I realize, of course, that these plants are not going to produce tomatoes under the low light and cold conditions of western Washington.  I simply want to make sure this method will work before going full scale with it next spring.  Since this picture was taken the plants have grown high enough that I've had to tie them up.  So far so good.  The next test is to see if 4 inch pipe will be big enough to support the root mass when the plants grow larger.  I have a feeling I might have to use 6 inch pipe which will give the roots twice the room.

Sixteen ounce Solo cups make great inexpensive pots for this system.   The holes in the pots are made with a soldering iron.  The holes in the PVC are cut using a three inch DEWALT hole saw.  The roots are thriving under these conditions.  The nutrients are used at 1/2 strength and supplemented with 1/2 tsp per gallon Magnesium Sulfate (Epsom Salts).  The nutrient level is maintained about 1 inch above the bottom of the pot (the bottom inch of the pot is submerged).

The water pump cost only $20 at Home Depot.  To keep the nutrients from freezing and help the plants grow faster I'm using an aquarium heater to warm the nutrients.

on to Lettuce DWC

Questions or comments?  Please contact me here: grass_man@oocities.com