Whether you're an avid hydroponic gardener or a beginner, you can grow nutrient-rich, delicious tomatoes indoors. Hydroponics systems are becoming more popular, especially for people who want a supply of organic and "free" vegetables all year long. To get started with growing hydroponic tomatoes, you can start your tomatoes from seeds or purchase young tomato plants from a reputable grower. With the right hydroponic garden system and some diligent care, you can grow the best tomatoes you've ever tasted.
Start your tomato seeds in 1-inch rockwool starter cubes. Presoak the starter cubes in water and adjust the pH to 4.5 before planting the seeds. You can adjust the pH by adding potassium hydroxide to raise the pH or phosphoric acid to lower it. Place the cubes in a standard nursery tray with a dome lid.
Store the covered tray in a moist environment at 68 to 77 degrees. When the seeds sprout, remove the dome lid. Place the tray under metal halide or fluorescent lights for at least 12 hours per day.
Transplant the seedlings to your hydroponic garden after 10 to 14 days when the roots poke through the bottom of the starter cubes and true leaves emerge. You can use several different kinds of hydroponic methods to grow tomatoes, but the drip irrigation system is most common for larger plants.
Use the expando system to grow your hydroponic tomatoes through drip irrigation. Place each plant while it's still in the starter cube in its own pot. Cover the seedling with heydite, which are small, porous rocks.
Provide approximately 1 gal. of nutrient solution per day for your mature tomato plants and slightly less for your young plants. Purchase a premixed nutrient solution designed for hydroponic use that is a two-part formula.
Move your lights one or two inches closer to your tomato plants every few days as the plants mature. Mature tomato plants need 16 to 18 hours of full light exposure per day, with eight hours of total darkness. Maintain room temperatures between 64 and 77 degrees during daylight hours and between 54 and 64 degrees at night.
Maintain the nutrient solution's pH at 5.8 to 6.3. Test the solution's pH regularly and adjust the pH when needed by adding potassium hydroxide to raise the pH or phosphoric acid to lower it.