Hydroponic gardens have been used for millenniums. Ancient cultures such as the Babylonians, Aztecs and Chinese have used one form of hydroponics or another. After World War II, experiments with hydroponics were performed by scientists and horticulturists in areas that do not have land or adequate soil for traditional gardens. Commercial gardeners began using hydroponics in the latter part of the 20th century. Hydroponic growth systems have become popular with home growers as well. Citrus fruits, such as limes, have been no exception to the expanding interest in raising quality, nutrient-rich produce without soil. Miniature and ultra dwarf varieties of limes are available through garden centers, catalogs and online distributors. These small trees produce an abundance of high-quality fruit that is perfect for the home grower. There are several hydroponic growing systems to choose from. The nutrient film technique (NFT) system does well for heavy feeding plants, such as ultra dwarf lime trees. You can purchase kits from garden centers and online dealers.
Purchase an NFT grow system and a table large enough to hold your grow system. You will also need grow medium (nutrients) that are specific to citrus fruits, rubber stall mats (your local feed store will carry these) and grow lights.
Choose a location for your grow system. An area that receives direct sun with little draft from windows, doors and air conditioners is optimal. You will need access to electrical outlets for the grow lights and air pump (included in most kits).
Install rubber stall mats. Place on the floor to keep the area from becoming slick with water. Set up the table on top of the mats. Assemble the NFT grow system according to the instructions included in your kit. Install grow lights over the hydroponics system. Lime trees require a minimum of eight hours of light per day.
Soak the roots of the seedlings in distilled water for at least 15 minutes. This will help remove any soil from the root systems. Plant the lime trees into net pots that are included with the hydroponic grow system you purchased.
Mix the grow medium in to your grow system, according to the directions on the package. Keep a daily check on the grow medium content of the water. You can purchase a pH analyzer from your local garden center. The lower the pH level the more acidic a substance; the higher the pH level the more alkaline (basic). A pH of 7 is considered neutral. Lime trees prefer an acidic solution with a pH level of 5.5 to 6.5.
Prune your lime trees on a regular basis to shape them and encourage fuller branch growth. Removing "leggy" or thin spindle-like branches will encourage thicker, sturdier branches to develop that will bear a large amount of fruit.