track of the total gallons of water you add. Add water-soluble fertilizer, such as 20-20-20 with micro nutrients, at a rate of 2 teaspoons of fertilizer for each gallon of water used in the water garden. In addition, add Epsom Salts (magnesium sulfate) at a rate of one teaspoon for each gallon of water. Use a soft broom to mix the water & fertilizer in the garden or premix all fertilizer in a bucket before adding to water garden”  One batch of nutrients per crop of lettuce is all that is required. A complete guide to this project can be found here

     Buy some of your cups of choice, 8 to 12 oz cups work well. Drill holes in the Styrofoam raft evenly spaced on 1’ centers. For a nice straight layout, use chalk string to layout a grid. Growing plants other than lettuce may require different spacing. Extra holes can always be plugged with empty cups.

     Here is one of the simplest forms of Hydroponics, the Floating Raft System. Find, buy or build a container to hold the nutrient and the raft. As pictured here, a 4’1” by 8’1” (inside dimensions) box built from 2x8’s or 2x10’s and lined with plastic works great. The reason for the extra inch in each direction is so a standard 4x8 sheet of Styrofoam will float with about 1/2” clearance on all sides. From Publication #HS943, “Fill the water garden with approximately 20 gallons of water. The water will form the polyethylene to the sides of the frame. Secure the other end and side of the liner to the top edge of the frame. Continue filling the water garden with water to a total depth of at least four inches. Keep

Here is a handy calculator to figure your gallons for a pond system. Measure your pond in inches, HxWxD = cubic inches.

The size of the holes depends on two things: the diameter of the cups being used and the thickness of the Styrofoam raft. The object is to have the cup protrude about 1/8” to 1/4” on the underside. The cups are filled with Perlite which will wick up the nutrient solution through the holes or slits you have cut in the bottom of the cup like in the picture. Use your coarsest Perlite for the bottom of the cup. Do not breathe the dust from Perlite. As an alternative to just placing your Perlite filled cups straight into the raft Commercially available net pots, you can purchase commercial 1.5” or 2” Net Pots.

     Again, size your holes so the container of your choice protrudes from the bottom just an 1/8” to a 1/4”. Take your seedlings from the Perlite filled cups you started them in and gently remove plant and Perlite from the cup, gently shake and tap the Perlite off, and place in the net pot. Don't try to get all the Perlite off. It is most important not to damage the roots. Plants you buy from the nursery can be done the same. Just tap

     Here is a video showing how the pro’s do it. This is the system I use for my commercial lettuce operation.