You don't have to give up on growing your own herbs if you live in an apartment or the soil conditions in your area won't support a garden. If you grow your herbs hydroponically, you can grow a mixture of herbs in a small space. Place your hydroponic herb garden in a sunny window or grow lights, and you can harvest your herbs year-round. Plant your hydroponic herb garden from seed to avoid introducing diseases on nursery plants or stressing plants that have grown in soil.
Test the water you will be using with a pH test kit, available at most lawn and garden centers. Add pH adjuster as necessary to achieve a water pH of 5.5 to 6.0.
Soak the starter cubes in the pH-adjusted water long enough to saturate them completely, and drain them.
Plant your herb seeds in the cubes. Some starter cubes come with pre-cut holes for the seeds. Use the tip of a clean pen or pencil to make a hole about a quarter to a half inch deep if your cubes didn't come with holes. Push one herb seed into the hole in each cube and cover it with seed cube material pulled from around the hole.
Place the planted starter cubes in a nursery tray and cover the tray with a plastic dome. Set the nursery tray in an area that receives indirect light.
Use plain, pH-adjusted water to keep the cubes moist--but not soaking wet--during germination. The seeds do not need nutrients during this time.
Begin feeding the seedlings a hydroponic nutrient solution diluted to quarter-strength when they emerge from the cubes.
Transplant your herb seedlings into your hydroponic system when the roots grow out of the bottom of the cubes.
Setting Up the Hydroponic System
Cut a sheet of 1-inch-thick Styrofoam so that it is 1 inch shorter than both the length and width of the inside dimensions of your aquarium or plastic tub. This will leave a half-inch gap between the foam and walls on all sides, allowing the foam to float freely on top of the tank.
Place a net pot upside-down on the Styrofoam sheet and trace it with a pen. Repeat this in each place you plan to put a plant. The number of plants you can grow will depend on the size of your tank and the size of the net pots you're using, but leave at least three inches between plants.
Turn your net pot right-side up and place it in the middle of each circle to trace it again.
Cut out the holes with a knife, keeping your cut between the two circles for each hole. This will give you a hole big enough to fit the pots without allowing them to fall through.
Adjust the holes as necessary to allow the net pots to extend about 1/2 inch below the bottom surface of the Styrofoam.
Fill your net pots about 1/3 full with a half-perlite, half-vermiculite mix or another hydroponic growing medium. Place your herb seedlings, still in the starter cubes, on top of the growing medium and fill the net pots to about a half inch below the rim.
Fill your tank with hydroponic nutrient solution to about 2 inches below the top to allow room for the Styrofoam growing platform to float.
Connect your air pump and air stone with air tubing and place the air stone in the bottom of the tank.
Place the foam sheet on top of the nutrient solution and place the net pots in the holes. As your herb garden develops, the roots will grow down into the solution.