GROWING MEDIUM; There are many growing mediums for hydro use. They include Rockwool, Vermiculite, Sand, Gravel, Expanded clay and others. Rockwool is used because it stays together and doesn't pollute the hydro juice. One Rockwool block ( About $A12 - $A30 ) will last for several crops of 6 plants. The Rockwool block is sealed in plastic and is about 700mm. x 300mm. x 100 mm. Before cutting the mats you need to see the grain of the rockwool the grain of in fig8. is from side to side. Cut across the grain with sharp knife several slices ( Mats ) 7mm. to 10mm. thick off the long side(fig.8). Each Rockwool mat is about 700mm. x 80mm. x 10mm. The Rockwool mats are passed through the slots and molded to the inside of the PVC pipe. This should cover the bottom inside half of each side of the root chamber with 7-10mm. of Rockwool mat. Be sure the Rockwool mat extends 50 - 100mm. longer than the slot. Next cut seedling blocks about 50mm. x 50mm. x 50mm.. Then poke a hole about 3mm. diameter from the middle of one side to the center of the block(fig.3). This hole should be large enough to let the seedling freely grow out the top of the seedling block. Make one block for each plant. These small blocks are used to germinate the seedling and support the growing plants.

The Rockwool should be prepared before using by soaking in water for 24 hours and then soak with fresh water for seeds or sprouts and in the root chamber with half strength hydro juice before the seedlings are transplanted.