Nigel's Gardening Hints and Tips
Created | Updated Jul 13, 2009
The mystery of Hydroponics
Hydroponics has been around since the Aztecs; it is slowly becoming more popular, especially with specialist plant nurseries where normal growing is not successful.
My first encounter was a specialist plant nursery down in Suffolk, which I went to visit for the day as part of my horticultural training. I can remember going into a big dark warehouse-type building which contained large glass greenhouse-type structures with a lot of bright lamps. We weren't allowed into these buildings as everything had to be as sterile as possible, which involved strict hand cleaning, white coats and hats. As we looked in through the thick glass, there were plant cuttings growing in special plant mineral gels with overhead growing lamps. It was interesting to see the different stages of each cutting as they grew and matured before eventually coming out and being repotted, ready to survive in the real world. Ever since that day, hydroponics has interested me and I think it is the future of horticulture.
Hydroponics is a way of growing plants without soil, in a nutrient-rich solution usually supported by a growing medium to sustain the roots and hold in moisture. Growing plants this way is a much faster method, as well as having the benefit of growing any plant indoors throughout the year. You can grow virtually anything using hydroponics, but some of the more faster growing plants will take up a lot of space quite quickly.
There are different types of Hydroponic systems, but the two most popular ones are called 'Deep Water' and 'Ebb and Flow' systems. The 'Deep Water' set-up consists of a deep container, which has water inside containing the dissolved nutrient content, as well as a pump on the outside to keep the solution well oxygenated. At the top of the container is a hole, which allows a net pot which contains the plant to sit in it. The net pot will contain a clay pebble medium in which the cutting or seed will sit, absorbing nutrients and water from the solution. The pump stays on the outside of the container, which feeds a tube to the airstone inside at the bottom of the solution, which does one of two things. The first is that it oxygenates the water and solution, which is essential for the roots of the plant; the second is to swirl the top level of the water, enabling the net pot medium to be soaked thoroughly enough to be kept moist, and store the essential nutrients needed for growth and survival.
As the roots grow and mature, the water level is lowered to allow some of the roots to hang in the air between the net and the level of the water.
The 'Ebb and Flow' system consists of large containers with a tray-like reservoir at the bottom, which is filled with water containing the nutrient solution. Each container (amounts vary according to size of system) holds a quantity of clay pebbles which absorb water and nutrients to supply the cutting or seedling in the centre, which is normally planted in a square open block to hold it upright. The containers have small pipes fitted to them, which lead into one central pipe linked to a pump in the reservoir. The system is plugged into a timer, which is plugged into your power supply. When the timer is activated, the water and solution are pumped into each container via the small pipes, flooding each unit. The clay pebbles absorb the water solution which feeds and waters the plant, before gravity pulls the water back into the reservoir for the next time. It usually takes three to four minutes to flood, and the same goes for the draining procedure. One of the useful benefits to this system is, that when the water is pulled back into the reservoir, the area in the container that it floods is replaced with clean oxygen enabling the plant to survive and grow. This procedure of flooding needs to be done up to two or three times a day, depending on what plants you are growing.
There are also other ways to create this 'Ebb and Flow' system. You can connect the pipes to one main pipe which leads into a water container, but this is usually used in larger specialised systems where the water solution is not re-used.
Other systems consist of a drip-irrigation-system where the container is filled with clay pebbles and the plant is in the middle, being watered/fed by a continuous slow drip formula into the pebble mixture. There is also a long-tray technique where the plants are in blocks, standing in the tray surrounded by a film to keep them upright. The water solution is in a small reservoir at the end of the tray, which is pumped through according to the timer. As the bottom of the tray is made on a slight slope, the water solution will drain back into the reservoir once it has been absorbed by the blocks.
These are the main types of Hydroponic Systems, the two that I talked about in detail are the commonest and best ones to use. There are a lot of different types of start-up kits available on the market now, but these can be quite costly, which is why a lot of people make their own.
It is also about getting the nutrient level right, according to what you are growing. This can be quite difficult and requires a lot of experience. There are some good simple starter packs, though.
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