Leaf lettuce is one of the easier hydroponic crops to grow. While any type of hydroponic system will give you lettuce, an added bonus for beginners is that you can make your own lettuce-growing system. Since a reservoir filled with water and nutrients is an essential part of hydroponic systems, always supervise small children around your hydroponic garden to prevent accidents.
Hydroponic systems use water that has had nutrients mixed into it. Ready-to-mix nutrients are available from any hydroponics supplier, or you can make your own by mixing 1 teaspoon of Epsom salts and 2 teaspoons of water-soluble fertilizer, complete with micro- and macro-nutrients, into each gallon of water. Most hydroponic systems use an inert media such as perlite, sterilized pea gravel or silica stones to physically support the plants. The media goes into individual net pots, which allow the roots to grow out and into the liquid, or it is used to fill planting trays that support multiple plants.
One of the easiest hydroponic systems for growing lettuce is a raft system, essentially a container full of nutrient-rich water with plants floating on top. Almost anything that holds water and is 4 or more inches deep works; use a plastic storage bin, a child’s wading pool or a wooden frame lined with plastic to get started. Put your lettuce in holes cut in a 1-inch thick piece of polyurethane foam and float it on the water. Set an aquarium-type air stone in the water and add an air pump to aerate the water and provide oxygen to the roots.
Ebb and Flow
An ebb-and-flow system consists of a plant tray, a reservoir, a submersible pump connected to a timer and the necessary hoses to move the water from the reservoir to the plant tray and back again. This system, also often called flood and drain, works by repeatedly filling the plant tray with water and then allowing it to drain back into the reservoir. The plant tray sits higher than the reservoir so that gravity does the work of draining it. Plants may be kept in individual pots or planted directly into media in the plant tray.
Growing lettuce in hydroponic systems offers many advantages over more traditional methods. Lettuce grows as much as 25 percent faster in a hydroponic system than in soil. No soil-borne pests or diseases to contend with, and no weeds to pull, either. You can grow enough lettuce for your whole family in a limited area, tucking your garden into a corner of a deck or patio if you wish. Small hydroponic systems are simple to move indoors, and lettuce can grow indoors under an inexpensive fluorescent shop light all year long.