462 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 8 



even fantastic ideas have been conceived, betraying a lack of knowl- 

 edge of elementary principles of plant physiology. For example, 

 there have been statements that in the future most of the food needed 

 by the occupants of a great apartment building may be grown on the 

 roof, and that in large cities "skyscraper" farms may supply huge 

 quantities of fresh fruit and vegetables. One Sunday supplement 

 article contained an illustration showing a housewife opening a small 

 closet off the kitchen and picking tomatoes from vines growing in 

 water culture, with the aid of electric lights. There has even arisen 

 a rumor that the restaurants of a large chain in New York City are 

 growing their vegetables in basements. 



Stories of this kind have gained wide currency and have captured 

 the imagination of many persons. Many factors have doubtless con- 

 tributed to arousing the surprisingly wide interest in the water- 

 culture method of crop production. The psychological effect of 

 current discussion of the wastage of soil erosion and soil depletion 

 has made the public especially receptive to new ideas relating to crop 

 production. Some people have been impressed by the assumed 

 social and economic significance of the water-culture method. Others, 

 moved by the common delight of mankind in growing plants, even 

 though the garden space is reduced to a window sill, have sought 

 directions to enable them to try a novel technique of plant culture. 

 The consequence of the discussion of this method has been the creation 

 of a great public demand for more specific information. Should this 

 newly aroused interest in plant growth lead to a greater diffusion of 

 knowledge of certain general principles of plant physiology, the 

 publicity regarding the water-culture method of crop production 

 might in the long run have a beneficial effect. Growing plants in 

 water culture has been considered by some popular writers as a "mar- 

 vel of science." The growth of plants is indeed marvelous, but not 

 more so when plants are grown in water culture than when they are 

 grown in soil. 



Sometimes two entirely distinct lines of investigation at the Cali- 

 fornia Agricultural Experiment Station, in which the water-culture 

 technique is used, have been confused in popular discussions. One of 

 these concerns methods of growing plants in water culture under 

 natural light, the other the study of special scientific problems of 

 plant growth in controlled chambers artificially illuminated. It is 

 economically impossible at the present time to grow crops commercially 

 solely under artificial illumination, even if there were any reason for 

 doing so. At several other institutions considerable attention has 

 been devoted to study of the effect of supplementing daylight with 

 artificial light during some seasons of the year, to control the flowering 

 period or to accelerate growth of certain kinds of plants (particularly 

 floral plants) in greenhouses, but this practice has mainly been applied 



