Hydroponics Gardening

Solutions and Medium Cultures in Hydroponic Review

Hydroponics is the growing of plants without soil. From the Latin meaning working water, water is used in hydroponic gardening to provide the nutrients to plants that they would normally get from the soil. There are many different ways to grow plants using hydroponic techniques, from small, in-house systems used by amateur gardeners, to large scale hydroponic operations used by farmers and those in the food production industry.

Though the applications vary widely, there are two main techniques used in hydroponic gardening; solution cultures and medium cultures. Solution cultures use nutrient solutions only; they do not include any solid medium for suspending the roots of the plants. Medium cultures, on the other hand, do use some kind of solid growing medium for encasing the roots of the plants. Within these two main types of hydroponic gardening, there are several sub-varieties of techniques.

There are three common types of solution cultures used - static solution culture, continuous flow solution culture, and aeroponics. In static solution cultures, plants are grown in some kind of container filled with nutrient solution. The containers can come in a variety of sizes and shapes, from mason jars and plastic buckets to tubs and tanks. The important thing about the container is that it be dark. If it is not dark in color, it should be wrapped in a dark colored film of plastic or aluminum foil. Plants are places in holes create on the lids of the container (or a lid you have designed for it). The solution is usually aerated; in which case, the roots of the plant should sit directly in the water. If the solution is not aerated, however, the roots should sit above the surface of the water so they receive oxygen. Many plants can fit in one container. The nutrient solution should be monitored and adjusted as needed as the plants grow.

Continuous flow solution hydroponics involved plants suspended about trough through which nutrient solution flows. This is a good way to grow mass quantities of plants, because the nutrient level can be monitored and adjusted at a central tank, which can then feed thousands of plants. One popular subtype of the continuous flow solution method is called the nutrient film technique, or NFT. In NFT, a plastic film covers the plants with their roots continuously supplied with nutrients. The roots then grow together, and a film of nutrients covers the plants.

When using the aeroponic technique, hydroponic growers suspend the plants, with the roots in a dark, covered container. A nutrient solution is then sprayed on the roots using either an aerosol system similar to those used in micro irrigation systems, or ultrasonic nebulizers

Medium cultures have two parts, sub irrigation and top irrigation. Passive sub irrigation medium growth cultures generally have large gaps, so oxygen can reach the roots. A system of capillaries takes water and nutrients to the roots. Top irrigation methods involve applying nutrients to the top of the medium growing culture. The nutrient mix can be applied once a day for small plants, or as many as five times an hour for a large system with a pump.

Medium growth cultures can be made of a wide array of materials, like rockwool, diahydro, coconut fiber, expanded clay, perlite, vermiculite, or even sand, gravel, and brick shavings. Each medium has its benefits and drawbacks, and the right one will depend on what kind of plants you are growing, what kind of container you are using and how simple or advanced your system is.