Organic hydroponic gardens are the best and most cost-effective way to know exactly what goes into the produce you eat. From the seed to the fertilizer to how much energy and water used, the gardener can control the results from the moment the seeds are planted to the last fruit picked. To make this project completely organic, Pam Johnson with Taos Hydroponic and Organic Garden Supply in Taos, N.M. suggests a system that does not use electricity.
Place the rockwool bricks in the tray and fill it partially with water, allowing the bricks to soak overnight. You will plant your seeds directly into the holes in the tops of the bricks later. According to rockwool manufacturer Grodan, rockwool is an ideal growing medium because it is made of volcanic rock that contains the nutrients plants must normally search for in soil.
Take your tray and place the elbow drains in the holes in the bottom of the tray. Place the bucket and tray so that the elbow drains allow water from the tray to spill into the bucket.
Plant two or three seeds into the hole in the top of each rockwool brick. You will not need to feed or water them for several days.
Place the tray in a warm, sunny location like a well-insulated windowsill or a sun porch. It is important to keep the plants warm since the bricks stay wet.
Water and feed the seeds after a few days. Mix the organic plant food into the water according to the ratios on the label. Use enough water to fill the tray to the top, allowing the bricks to absorb the water as it drains into the bucket. You can use the water in the bucket when you water the plants again. The plants will need to be watered in this way about twice a day.