Hydroponics is a system in which the plants grow in nutrient-rich water instead of soil. Tomatoes are common hydroponic plants because of their ease of growth and solid plant structure. Hydroponic systems produce tomatoes year-round and have the benefit of reduced disease and insect problems. The harvested tomatoes are flavorful and superior to those grown in an outdoor garden since the nutrient concentration and pH are easily controlled.
Grow seedlings by sowing one seed per water-soaked rockwool cube. Set the rockwool cubes in a covered growing tray. Place the tray in a location that is approximately 70 degrees F with indirect sunlight. Remove the cover when the tomatoes have sprouted. Put the tray under grow lights or in a sunny area.
Transplant the rockwool tomato seedlings into a hydroponic growing container when the true leaves appear and the roots can be seen through the bottom of the rockwool cubes. The seedlings will be ready for transplanting in approximately 10 to 14 days.
Set the tomato seedlings into hydroponic netted pots filled with a hydroponic medium or into larger rockwool planting cubes. Small rockwool cubes used for planting the seeds do not need removing. Space the tomato plants 10 to 12 inches apart in the system.
Test the pH level of the hydroponic water to make sure it has a pH of 5.8 to 6.3. Increase the pH by adding potassium hydroxide or lower the pH by adding phosphoric acid to the water.
Monitor the water pH and nutrient level to make sure the plants receive the nourishment needed for growth. Add a hydroponic nutrient mix to the water as needed. Follow the label instructions.
Grow the tomato plants under metal halide lights for 16 to 18 hours each day.