Cilantro, also called coriander, is an herb often added to Asian and Mexican dishes. The plant, from the carrot family, produces lush foliage that you harvest before the blossoms and seedpods appear. Cilantro seeds are hard and may take up to 14 days for germination. Once sprouts appear and are transplanted into a hydroponics system, the plants grow quickly when adequate nutrients are available through the water.
Soak 1-inch wide rockwool planting cubes in a tray of water for two hours. Pour off excess water and drop two or three seeds into the center of each cube. Cover the tray with a clear plastic bag or sheet of plastic wrap and place in a warm area with indirect light.
Monitor the seed germination and spray the cubes with water three to four times a week to keep them moist. Remove the plastic once sprouts appear and move the tray to a sunny area. Spray the cubes once a day to prevent them from drying out.
Assemble the hydroponics system once the cilantro plants are 2 inches tall. Fill the system with water and turn it on to verify everything is working properly.
Add nutrients to the water following the package instructions for the water volume in the system. Liquid fertilizer is about 3 tbsp. for every gallon of water in the system. Add nutrients to the water each time you refresh or add more to maintain an adequate level of nutrients for plant growth.
Plant the cilantro seedlings in the hydroponics system by inserting the 1-inch cubes into 3- or 4-inch cubes that fit the system you are using. Do not remove the seedlings from the small cubes, the design allows you to insert them into larger cubes to prevent root damage. Cilantro develops a taproot, which does not like to be disturbed.
Place a halide grow-light system over an indoor hydroponics system. Set the lights 6 inches from the top of the plants with the light on for 12 hours each day. Raise the lights as the cilantro grows taller to promote upward growth and prevent burning the herb.
Clip the leaves from the cilantro plant once it begins to branch out and taller than 8 inches. Remove blossoms growth to prevent the plant turning bitter in taste.