Hydroponics is a method of growing plants in water instead of soil. This method allows you to grow vegetables and other plants indoors throughout the year without worrying about harsh winter weather. Tomatoes adapt well to the hydroponics environment and produce strong plants with high fruit production when cared for properly. Tomato plants grown with hydroponics have few problems with damage from insects and disease, because most of those threats are soil-borne.
Plant tomato seeds to create seedlings for the hydroponics system. Sow the tomato seeds by placing one each in a small hydroponics rockwool cube that is water soaked. Place the cubes in a covered growing tray and set in a warm location with filtered sunlight. The top of a refrigerator works well. Remove the cover once the seedlings reach 1 inch in height.
Transplant the tomato seedlings once they are several inches tall and have a set of true leaves. This will take approximately 12 to 14 days.
Plant the tomato seedlings in the hydroponics system. Set the entire cube into netted pots or larger rockwool cubes. Do not remove the small rockwool cubes, because doing so could damage the root system. Space the planted seedlings 10 to 12 inches apart in the hydroponics system.
Fill the hydroponics system with water. Test the water pH level to verify it is 5.8 to 6.3, the preferred level for tomato plants. The tomato plants will not absorb nutrients when the pH is too high or low. Add potassium hydroxide to increase the pH or phosphoric acid to lower the pH.
Purchase hydroponic nutrients and add the mixture to the water based on the package recommendations. The amount needed will vary based on the amount of water cycling through the hydroponics system.
Monitor the water pH and make adjustments as needed. Add nutrients to the water when refreshing or adding water to the system.
Place indoor metal halide growing lights over the tomato plants and turn them on for 16 hours each day. Tomato plants need long periods of light to produce blossoms and fruit.