Garden innovations - hydroponic gardening

Hydroponics might sound like some futuristic invention, but it simply means growing plants without soil. Instead, the gardener uses specialised food, called hydroponic nutrient which is dissolved in water and fed directly to the roots using an automatic feeder system. Plants are grown in what is called an inert grow media and this means they form smaller roots, putting more energy into their crop.

The purpose of an inert grow media is to aerate and support the root system and to channel water and nutrients. Different growing mediums work well in different hydroponic systems. A fast draining medium, such as Hydroton or expanded shale works well in an ebb and flow type system. Rockwool, also known as mineral cotton, silicate cotton and stone wool was originally used in construction as insulation but has become one of the most popular inert growing media - but it is alkaline and this needs to be compensated for in the way nutrients are used. Others include perlite, vermiculite and different grades of sand, all of which rarely affect the pH of the nutrient solution, although they may hold too much moisture and should be used with plants that are water tolerant. Perlite, vermiculite and sands are very cheap options, so they are good for beginners and work best in wick, rather than ebb and flow systems.

A hydroponic nutrient solution contains all the elements the plant would normally extract from the soil, and are available as liquid or powders that dissolve into a reservoir - the cheapest versions do not have a pH buffer so they are not suitable for use with rockwool.

Like soil, hydroponic systems can be fertilized with organic or chemical nutrients, but an organic hydroponic system is considerably more work to manage as the organic compounds have a tendency to bind together which cause pump to block.

The two main advantages to hydroponic systems are that crops tend to be bigger and faster than soil grown equivalents as the plant doesn't have to use so much of its energy to convert fertilizers to growth, and people who can't garden can still use hydroponics to grow vegetables, which is particularly useful for the disabled and elderly, for example.

Garden innovation hydroponic photograph by ibitmylip, used under a creative commons attribution licence.