Hydroponics

the answer lies in solution

Hydroponics is the art and science of growing crops without using soil, by feeding them on solutions of water and nutrients which contain all the vital elements necessary for quick and healthy development.

At first glance, such a method of cultivation might well strike the average householder or gardener as being directly opposed to traditional systems of tilling the ground, and indeed-following the views of some schools of thought - as unnatural.

Yet, if we will but take time to make just a brief study of the relevant facts we will soon see that although hydroponics is of course very different in practice to conventional farming and gardening, it is actually a completely natural technique, based on accepted ecological principles, and combining high productivity with several important environmental advantages for both plants and human beings.

In modern industrial societies, few persons, even if they are lucky enough to possess a plot of earth, have the opportunity-or the energy after a hard day's toil in factory or office - to dig, manure and weed the soil in order to produce green food for themselves and their families. In addition, the problem of space is fast becoming more serious and there are millions of people who would like to garden at weekends but who have not got any room to do so.

Meanwhile, the prices of vegetables and fruits sold in shops and markets increase rapidly and constantly, putting ever greater strains on already hard-pressed household budgets and depriving men, women and children of the benefits of fresh produce, always essential for a balanced and healthy diet.

It is therefore not surprising that today more and more persons are turning towards hydroponics as a means of providing regular supplies of green foods and fruit in their homes. Gardening without soil can be very attractive to flat dwellers, people living in apartments or in tower blocks, in overcrowded cities and suburbs, or in other congested surroundings, whose resources are limited.

Because hydroponic methods take up much less space than soil gardening would they are ideal for such situations. Moreover, soilless crop growing demands no hard manual work, and there are no jobs to perform comparable to those of digging, manuring and weeding the earth. Provided a few simple rules are adhered to, anyone can operate a hydroponic unit successfully in conditions where ordinary soil gardening would be impracticable.

The term `hydroponics' means litreally `water working' and is derived from the Greek words budor, water, and ponos, work. It was first used by Dr. William F. Guericke, of the University of California, in the mid-1930's. Since that-time, of course, many advances have been made in soilless cultivation, so that we now find hydroponic techniquess well established in many areas of the world.

Numerous different methods of soilless crop growing have been developed, adapted to contrasting circumstances, such as climate, geography, finance and levels of technology. Thus there are hydroponic systems for large commercial farms, others for desert or barren regions, and still more for householders, amateur gardeners and those persons interested in selfsufficiency and diverse life-styles.

Plants need certain essential items to grow and produce harvests. These include: light, air, water, a support for their roots, and food. Air is a gift of nature; light may be too but it can also be provided by man in the form of electricity; water similarly can come from rainfall or by pipe and well; a support for the roots can be supplied through different devices; while food may be offered in convenient and ingenious ways, which are completely acceptable and satisfactory to the plants.

In hydroponics, we strive to create the best environmental conditions for crops. Instead of giving plants earth and manure to feed on or anchor their roots in, we provide them with certain types of substrates or growing media and nourish them on solutions of water and fertilizers. Various misleading statements are made from time to time asserting that hydroponic methods of culture are artificial and that the produce from soilless units is lacking in nutritional value.

Now although it may well be that food produced in factory farms is tasteless and inferior, this is not the case with hydroponic produce. In fact, the flavour and palatability of fruits and vegetables grown without soil are excellent, because the plants receive maximum feeding with a well balanced range of nutrient elements.

Extensive tests and analyses have indicated that the mineral and vitamin contents of hydroponic crops are fully up to highest quality standards. Flours from hydroponically grown wheat have proved better for bread making, while it has been possible to incorporate extra iron and calcium in tomatoes and other vegetables for feeding to babies and invalids.

On farms, it is now possible to grow grass without soil in special hydroponic units, for feeding dairy cows and beef stock, which matures in seven days after sowing. This green forage is extremely high in protein and mineral content and greatly increases milk yields and the health and well-being of cattle or other livestock.

Agricultural scientists and farmers, know very well that excessive artificial fertilizers, without the use of any humus, destroy the tilth of, and degrade, the land. But they continue to employ them alone or in unbalanced quantities for purely economic reasons to get money as quickly as possible, without thought for the future. This is the chief criticism that can be made of modern farming.

Evils such as erosion, disease, and destruction of the environment follow upon this abuse of the good earth. But in hydroponics there is no land to destroy, so any such complaint cannot be made. On the contrary, by creating vegetation where there has been none, hydroponics performs a most valuable ecological function.

The hydroponic method, in practice, means that instead of applying organic or inorganic manures to land, where they have to be, in the first case, broken down by bacterial action before they can be assimilated by green plants, the fertilizers are given direct as solutions to the crops. Higher plants cannot absorb immediately organic materials. A considerable time must elapse before the necessary changes take place to make the nutrients present in such substances available to crops.

What we are doing in hydroponics is simply to shorten this period dramatically, thus providing immediate nutriment in well balanced form to plants. This is why growth is so much more rapid in soilless cultures and the crops thrive so well. The process is perfectly natural li and is in fact much safer and ecologically more sound than the current soil farming practice of spreading vast unbalanced quantities of chemicals over the countryside.

GROWING METHODS
Many different systems and method of hydroponics are in use throughout the world today. Whilst some of these techniques are intended to serve the purposes of large commercial growers, quite a number are ideally suited to the needs of households, communities and families, for self-support and home production.

Naturally, it is advisable to consider carefully the standard of education and the general social and technological development or condition of any community-those which exist or those which may be desired-when recommending a hydroponic technique for particular circumstances.

It would be useless to introduce certain practices, perhaps well suited to a peasant population living in under-developed surroundings, to a more intellectually advanced group in an industrial situation.

Quite apart from differences in tastes and habits, there is a need to provide a viable level of operations for each case, or else skills present in the people concerned would be wasted. This is good ecology-to match the system to the subjects concerned, so that a satisfying and balanced lifestyle is secured.


Let us now consider a few methods of simple hydroponics for food production:

(a) Sand or aggregate culture. Very cheap hydroponic units can be made by lining wooden greengrocers' boxes or similar containers with polythene plastic sheeting or by using plant pots and plastic troughs. Normally, such receptacles should not be less than six inches deep and not over two feet wide, though they may be of any convenient length.

For larger areas, beds or troughs, some eight inches deep by a yard wide and again of any appropriate longitudinal dimension, can be prepared by stretching the polythene sheeting over the ground or bare surface available, and supporting it at the sides and ends by bricks, stones, boards or other means.

It is, however, possible to make almost any shape of trough or container to fit in with the circumstances of a backyard, kitchen, rooftop or other site. Many other good places exist for soilless gardens around the home, such as window sills, verandahs, the sides of pavements, and waste ground.

Once the hydroponic container has been chosen and lined with polythene, if necessary, a small drainage hole should be made in the base, or if it is a very large and long trough then several holes must be made. In the case of pots, there will be no need to do this because apertures will already exist in their bottoms.

Drainage holes are generally about'/ inch in diameter and can be provided with removable plugs. The purpose of these is to allow excess moisture to seep from the troughs Or pots. Gutters may be provided to catch this liquid, or saucers and trays can be placed underneath pots.

The next task is to fill the container with growing medium. This is the substrate which anchors the plants' roots in position and acts as a reservoir for the water and fertilizers. Sand, fine gravel, wellbroken bricks, washed cinders and charcoal, vermiculite, and many other materials will make excellent growing media.

Allow the substrate to come up to about 1/2 inch below the top of the sides of the container. Then smooth over the surface carefully. Some hydroponicists like to put an inch or two of pebbles or broken stones of larger size at the bottom of the troughs or pots beneath the main growing medium to ensure better drainage and aeration. Sands for hydroponics should be of medium and coarse grades, while the best sizes for gravels are 1/8th to 1/4 inch.

The hydroponic trough or container will now be ready and should be watered with plain water to make the growing medium about as moist as a damp sponge that has been lightly wrung out. Excessive watering is bad, the containers should not be kept flooded or water standing in them because this prevents air from reaching the plants' roots. Sow seeds not more than 'h inch deep in the substrate, or plant young seedlings by scooping out small holes in the growing medium and pushing back the material gently around the stems so that they will stand firmly.

Spacing may be up to 50 per cent closer than in soil gardening. It is a good plan to raise seedlings at home for hydroponics by sowing the seed first in small boxes of sand and then transplanting the young plants, when they are about three inches in height into the main containers.

After sowing or planting have been completed, feeding or nutrient application must commence. Nutrient mixtures can be made up at home or may be bought ready-made. If the first course is adopted, the mixture shown in table 1 is a good general purpose one for hydroponics. Weigh out these salts on ordinary scales and mix them well together, storing them in a dry sealed container. Larger amounts may be prepared by multiplying all quantities by a constant figure, so that the proportions stay the same.

To apply the formula to the hydroponic garden, mix one-third of an ounce, which is about one standard unheaped teaspoonful, with one gallon of water and spray or pour as many gallons of this solution onto the surface of the growing medium as may be necessary to keep it continually moist, but not flooded or too wet. This should be done as ofter as necessary. In winter, application of nutrient solution once or twice weekly should suffice, but in warm, dry summer weather daily additions will probably be needed.

The solution can be applied in small units by watering can, but in larger troughs or beds it is easier to place it in an elevated tank or drum and allow it to run down through a hose pipe onto the growing medium. Whilst application is in progress, and for a short time after, keep the plugs in the drainage holes. Later, these apertures may be opened, to allow excess moisture to escape and air to be drawn into the substrate. The seepage can be collected in a bucket, tray or sump and returned to the tank.

Once weekly, open the drainage holes, to permit surplus liquid to run off, and every two or three months flush through the hydroponic containers with fresh plain water to remove any accumulated residues, and then start again with solution applications.

It is important to keep all hydroponic gardens clean and well cared for. During absences, for instance, on holidays, bowls, buckets or tanks of solution may be placed beside troughs or containers, and strips of cloth or wicks, with one end dipped into the nutrient liquid and the other inserted in the growing medium, to convey water and nutriment to the crops

(b) Bengal method This is similar to the simple sand or aggregate culture already described, except that the growing medium or substrate is composed of a mixture of about two parts of coarse sand and three parts by volume of fine gravel, pebbles, broken bricks or other materials, all well blended together. The substrate is kept constantly moist, just like a damp sponge that has been lightly squeezed out.

The method was devised in India, where great poverty exists, and because not many persons could afford solution tanks, the technique of dry application is employed. This means that after mixing up the formula the nutrients are scattered evenly over the surface of the growing medium at the rate of between one and two ounces of nutrient per square yard of trough space. Spreading of dry nutrients should be done on average weekly.

Immediately after sprinkling the salts, they must be watered with plain water from a can or hosepipe, so that they dissolve and are washed down into the substrate in solution, to become available as plant food to the crops' roots. In between the times of nutrient spreading only plain water is given as irrigation to keep the troughs always damp.

(c) Sharder process. In order to help people who dislike using fertilizers, or those living in areas where local conditions make it difficult to obtain adequate supplies of inorganic nutrients, a process called the Sharder technique has been developed, also in Bengal. Normal beds or containers of aggregate are used, but to provide the crops with nourishment, manure shells or pots are placed at intervals along the troughs. These consist of earthenware vessels, lined with some kind of sieve or screen and pierced by a number of tiny holes in the bottom. The pots are filled with a nutrient sludge or semi-liquid manure, a typical formula for which is:

Fresh or dried dung. . 1 handful ......
Matured oilcakes . . . 4 teaspoonfuls

Alternatively, such materials as hoof-and-horn meal, bonemeal, shoddy, or similar plant foodstuffs can be utilised. Dried wood ashes are also fairly effective. To mature the oilcake (cotton, castor, groundnut or other feed cake or waste) knead it with a little water, add ground bones together with some potash (fresh wood ashes or saltpetre), then store in a closed container for about two months. This disposes of any odours.

When the manure shells are placed in the hydroponic troughs, and sunk a few inches into the aggregate, with only the upper portions remaining exposed, they slowly release their nutrient contents into the substrate. Covers should be put over the vessels, and from time to time they may be refilled with nutrient sludge or topped up. Every three months, flush through the beds or containers with plain water to cleanse them. Normal irrigation with water is provided to keep the substrate always moist. It should be noted that this process may be classed as organic feeding.

Table 1
Fertilizer .....................Ounces
Ammonium sulphate ....15
Potassium sulphate ......3%
Superphosphate ...........5
Magnesium sulphate .....3
Ferrous sulphate - enough to cover
the head of a match

Table 2
Manure.................................Ounces
Hoof-and-horn meal ................15
Bonemeal ..............................8
Ground chalk .........................6
Ground magnesian limestone .18
Fresh wood ashes .................20
Scrapings from a rusty iron nail -
enough to cover half a teaspoon

The formula shown in table 2 may be used in towns or industrial areas.

Mix well together and dilute to a thick sludge with water. Place in pots of about 2 lb capacity each, prepared as already described, and set them at intervals of up to one yard apart in the hydroponic units. The bottoms should be sunk three inches into the substrate. The sludge will slowly percolate into the growing medium, providing plant nutrients.

See that it is not too thick and that the liquid strains slowly out of the vessels into the troughs or containers. It should not however run too rapidly. Top up with water and fresh formula monthly. Larger amounts can be made by increasing the total bulk, keeping the relative proportions constant.

Self-sufficiency, eco-houses and various forms of alternative technology, are today of increasing importance. Several designs have been proposed, and used, which include the hydroponic production of green food based upon the adaptation of domestic waste matter for the nutrition of home grown crops.

Waste and excreta, after processing by anaerobic digestion, algae farming, and other treatments, can be employed profitably, thus making for a self-contained life support system. When such organic nutrition is favoured, production of methane gas can be undertaken as well, so providing heat in cold periods.

Ingenuity and inventiveness, together with technological adaptations, have come to make hydroponics an ideal means of producing large amounts of foodstuffs very economically in quite simple ways, thus providing a significant contribution to ecological living. The field is open to farther developments and we should see numerous such units in existence in the future.

by James Sholto Douglas