Hydroponics is a system of soil‐free gardening. The term comes from the two Greek words: hydro meaning water and ponics meaning labour and while the term is a modern one, the technique has been around for millennia – the hanging gardens of Babylon, one of the fabled wonders of the world, were a form of hydroponics.
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Modern Hydroponics
The end of World War Two led to several countries experimenting with forms of gardening that could be sustained under the demands of bombing raids and the threat of nuclear war, and hydroponics rapidly became the most likely solution to the problem of gardening without land. In Holland and Germany in particular, forms of market gardening using hydroponics have proved very popular and productive.
Benefits of Hydroponic Gardening
The adherents of the hydroponic principle claim several key benefits to this way of growing:
- They say growth rate is faster – up to 50% faster in some cases – than that of a soil‐grown plant and that plant yields are higher because the nutrients it needs are mixed directly with the water so the plant doesn’t have to search them out or convert them before it can use them for growth.
- They also claim that hydroponic plants have fewer problems with insect infestations and plant diseases. It’s certainly true that there’s no weeding necessary and no soil borne diseases to contend with!
- Paradoxically, the hydroponic garden also uses less water than soil‐based gardening! This is because the solutions used in the system are constantly recycled.
- A key argument is that those living in climates that don’t naturally support vegetation, such as the arctic and Antarctic, and desert regions, could use hydroponics without putting stress on the environment.
How it Works
A growing medium such as expanded shale or a clay aggregate, rockwool, perlite, vermiculite or certain kinds of sand are used as a ‘grow rock’ through which the nutrient solutions are circulated. Each has its own advantages and disadvantages depending on the space available, the plants to be grown and the amount of reuse required.
Hydroponic fertilisers, or nutrient solutions are purchased in liquid or powder form and mixed with water – usually there are two different forms: one to promote early growth from seed and one to encourage blooming and fruiting.
Hydroponic nutrients can be either ‘chemical’ or ‘organic’ although the organic compounds are considerably more prone to ‘locking’ the system by forming blockages because their constituent ingredients are not as uniform as the manufactured nutrients.
Chemistry
The pH of a hydroponic system is vital to maintaining plant health. Most systems suggest keeping to the pH range of 5.8 ‐ 6.8 with 6.3 usually featuring as the ideal. It’s much easier to check, and alter the pH of a hydroponic system than that of soil, but unlike soil, a hydroponic system only contains what the grower supplies to it, so if the pH goes out of range, the plants can’t find any alternative nutrients to keep them healthy and die very fast. This does mean twice‐weekly checking of the system as an absolute minimum in the first few seasons, so it’s not the route for growers who like to take lots of holidays or weekends away, unless they have a totally reliable person to do their maintenance for them.
Once an entire growing year (or maybe two, in variable climates) has been run through, a hydroponic system can be almost entirely automated, requiring a weekly pH check and water circulation at most.
