Gardening Tips on Hydroponics
What is ‘hydroponics’? Generally this term is used to describe all kinds of methods of growing plants without—in water, sand, gravel, vermiculite or other soilless substances—although, strictly speaking, true hydroponics is solely water culture.
In recent years there have been signs of a growing interest in hydroponics. A number of convenient proprietary kits and simplified methods are now on the market; the increasing cost of soil—and the success of soilless composts—have been an added stimulus. The home gardener can now use hydroponics on a modest scale for a very low initial outlay. There has been greater progress in popularizing hydroponics for growing ornamental plants than for raising crops. One reason for this is that many people have a resistance to eating vegetables or fruit that have not been grown in the soil. It is important to point out, however, that at the moment there is no scientific evidence that artificially-grown plants are in any way lacking in the nutritional value of soil-grown crops.
The basic idea of hydroponics is to support the plants either by some kind of mesh cradle or in a solid soilless medium, and to supply all the necessary nutrients in solution in water.
In order to produce heavy crops from any plant, certain essential conditions must be provided: adequate water, air, light, warmth, food and freedom from pests, diseases and pollution. All these demands must be met in hydroponic culture just as in soil culture, but one point requires particular care. This is the aeration of the root medium, to ensure an ample supply of oxygen. Regular irrigation of the aggregate and close attention to the food content of the solution is also needed.
Advantages and disadvantages
With soilless cultivation, it is relatively easy to grow crops of consistently high quality, because there is no variation in soil, drainage, fertilizer uptake and so on. Consistently high yields can also be obtained, provided that the plants are grown under optimum conditions of light, temperature and other growth factors. Soilless methods are labour-saving because digging andare not needed; manuring and crop rotation are also unnecessary.
Provided that the solutions are well aerated, waterlogging cannot arise be-cause in aggregate culture, the root medium is naturally free draining.
Root troubles are virtually eliminated, and, in the case of aggregate culture, as soon as one crop is finished, the containers and rooting medium can be sterilized easily and quickly by means of chemicals such as formaldehyde. Crops of a consistently high quality can be regularly and easily grown.
Long-term running costs are lower than with conventional soil methods, because once the installation is established. The life of the rooting medium continues indefin’tely.
Hydroponics and aggregate culture have some disadvantages. The initial cost is high, and in cooler temperate climates these methods are more suited to indoor or covered cultivation than outdoor installation because of the variations in rainfa!1 and temperature.
Where fully automated systems are employed, it is necessary to install a mains electricity supply and control gear.
Due to the high degree of precision required in controlling moisture, air and nutrient level, the margin of error is very fine, compared with conventional soil culture. With aggregate culture, watering must be done more frequently than with conventional soil culture.
Hydroponics or water culture
In its most simple form, this can consist of an earthenware or plastic reservoir containing the nutrient solution; suspended above it is a plant resting on a mesh cradle with its roots in the liquid. The principle is the same for larger commercial installations.
The practical problems of this system are: providing adequate support for the plants; keeping the solution dark to prevent algal growth; keeping the pH (acidity) of the soil at the right level; aerating the solution: and maintaining the correct level of liquid.
One popular hydroponics kit, for germinating seeds, relies on the principle of floating the seeds on a raft of perlite granules in a shallow tray containing water and nutrient The seeds are covered with non-absorbent dark-coloured material to prevent the growth of algae and to shade the germinating seeds so that the root system can develop and grow downward.
This system overcomes the nutrient problem by having specially compounded slow-release fertilizer pellets included with the kit; these are placed alongside the seeds. To prevent the roots of thefrom becoming tangled together, the tray is divided into sections by sloping panels, which also act as supports for the seedlings. When they are ready for planting, the seedlings are teased out or gently flooded out of the perlite, so that there is little or no damage to their delicate root systems.
This method is particularly recommended for germinating vegetable seeds.