WATER-CULTURE METHOD — HOAGLAND AND ARNON 473 



Claims of unusual nutritional value for food products from certain 

 sources should not be accepted unless supported by results obtained 

 in research institutes of high standing. 



PRESENT STATUS OF THE COMMERCIAL WATER-CULTURE METHOD 



What is the justification for considering the water-culture method 

 as a means of commercial crop production? The answer to this 

 question is that the method has certain possibilities in the growing 

 of special high-priced crops, particularly out of season in greenhouses, 

 in localities where good soil is not available, or when maintenance of 

 highly favorable soil conditions is found too expensive. Soil beds in 

 greenhouses often become infected with disease-producing organisms, 

 or toxic substances may accumulate. Installation of adequate equip- 

 ment for sterilizing soils and operation of the equipment may require 

 considerable expense. Also, in theory at least, a water-culture 

 medium, when expertly supervised, should be subject to more exact 

 control than a soil medium. 



Present information does not warrant a prediction as to how widely 

 the water-culture method will find practical application in green- 

 houses. One firm in California has reported success with this method 

 in the production of tomatoes ; another California firm which invested a 

 large sum in equipment, met such serious difficulties that the equip- 

 ment was not being utilized at last report. We suggest that those 

 who contemplate installation of the water-culture method for com- 

 mercial purposes, make a preliminary test with a few tanks of solution 

 to compare the yields from soil and water-culture media, and to 

 learn some of the requirements for control of the process. However, 

 without some expert supervision, commercial success is unlikely. 



Indispensable to profitable crop production by the water-culture 

 method is a general knowledge of plant varieties, habits of growth, 

 and climatic adaptations of the plant to be produced, pollination, and 

 control of disease and insects; in other words, the same experience 

 now needed for successful crop production in soils. 



The above discussion is primarily based on experiments with green- 

 house crops. Conceivably in regions highly favored climatically, and 

 with a good water supply available, but where soil conditions are 

 adverse, some interest may arise in the possibilities of growing crops, 

 outdoors, commercially, by the water-culture method. What crops, 

 if any, could be grown profitably by this method would depend on the 

 value of the crop in the market served, in relation to cost of production, 

 which would include a large outlay for tanks and other equipment 

 and materials, as well as special costs of supervision and operation. 

 Thus far, no evidence is available on which to base any prediction 

 as to future development of the water-culture method of crop 



