Books of the Day
Soilless Gardening
Complete Guide to Soilless Gardening. By William F. Gericke. ,Putnam.. 125. 6d.) Complete Guide to Soilless Gardening. By William F. Gericke. ,Putnam.. 125. 6d.)
SOILLESS gardening, once called by the simple and sensible name of aquiculture, now hydroponics, by which commercial crops and flowering plants may be grown without soil in specially constructed tanks of water treated by certain chemical nutrients, has made an appeal to public imagination that might be compared with that first made by broadcasting twenty years ago. The apparent miracle of transmitting and receiving voices and music without wires appeals to a lay public in much the same way as the apparent miracle of growing plants without soil. This appeal has already been manipulated by the Press and by some commercial firms offering, sometimes for a few shillings, some-
times at exorbitant prices, the pocketed chemicals and instructions necessary to perform the trick of growing bumper
crops in the back-yard bath-tub. Any such attitude, by which hydroponics is treated as a stunt, is both absurd and dangerous. Hydroponics, by no means a new discovery, is the practical application to horticulture and agriculture of certain scientific processes, themselves worked out by exhaustive experimental practice. In Dr. Gericke's own words, it " is based on the theory that all the factors of plant growth naturally supplied by
the soil can be co-ordinated artificially by the use of water and chemicals into a crop-production method capable of com-
peting with agriculture." This does not mean that " the nutrient solution will take care of everything, and that, like Topsy, the crops will just grow." Hydroponics, as Dr. Gericke is careful
to point out, is not yet an exact science' there are no magical
formulae ; care must be taken in selecting the crops to be grown, and with certain crops the established methods of agriculture will yield better results than those of hydroponics ; complete success depends on an ability to " combine to some extent the knowledge of the chemist, the botanist and the farmer " and on the " skill in working out a proper technique indescribable in text-book language."
Hydroponics, therefore, offers not so much a solution to the amateur as a challenge of a problein. Throughout Dr. Gericke's book there runs a cool note of warning. The cost of hydroponic equipment is, for some crops, impossibly high ; in determining the constitution of the nutrient solution it is necessary to know the composition of the water to be used ; without this knowledge the correct chemical mixture is almost impossible, since " large quantities of solutes in the water may upset the life processes of the plant by physical force." Equipment must be strong and durable. It consists of basins, six inches or less in depth, con- structed of concrete (great care needed again), sheet metal (still more care), or wood. These basins, which are the largest items of cost in hydroponics, hold the nutrient solution. Above them, in a wire-netted seed-tray, the plants germinate, thrusting down long fibre roots which derive nourishment from the solution below. Seeds will germinate in a seed-bed of vegetable litter: leaf-mould, sawdust, peat, wood-shavings, straw, chaff or ordinary soil. Whether germinated in this way or in soil, in the usual way, and subsequently pricked out, it appears that plants establish themselves more rapidly than under ordinary agricul- tural conditions.
Dr. Gericke's book is American • its advice and conclusions, admirable in themselves, are based entirely on American experiments. The English reader, faced with the knowledge
that English climatic conditions differ greatly from those in the United States, will rightly wonder if hydroponics has an equal chance of practical success in his own country. Throughout the book labour and material costs are given in dollars ; crops are listed which we do not grow. Nevertheless, it appears probable that most flowers, many agricultural crops and most market garden vegetables and saladings may be grown under hydroponic conditions with an excellent chance of higher yields and lower costs than under ordinary conditions. Whether any commercial grower in this country has confirmed or disproved this I cannot discover. It is odd that the impression left of an extremely able, authoritative and balanced work should be one of scepticism. Yet this is the impression left on me by Dr. Gericke's book : the impression that hydroponics, whatever its potentialities, has not Yet reached the stage where its adaptation to the life of the community can be either very wide or very practical. As the cinema and the radio only supplemented the drama and the gramophone instead of killing them according to prophecy, so
n,Ydroponics will, I think, never displace the established methods of soil culture. This view does not at all, mean that Dr. Gericke's very thorough, sensible and in places highly technical work should be missed. On the contrary, it deserves minute attention. H. E. BATES.
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