THE HORTICULTURAL SOCIETY OF NEW YORK 



ELECTRIC LIGHT IN GREENHOUSE CULTURE 



By Prof. Hugh Findlay, Columbia University. 



Lecture delivered April loth, 1924, American Museum of Natural 



History. 



{Dr. E. B. Southwick, presiding) 



ONE of the first important records of an experiment to ascer- 

 tain whether electric light exercised any decided effect upon 

 the growth of plants was carried forward in 1880 by C. Wm. 

 Siemens. D.C.L., LL.D., E.R.S., Mem.Inst.C.E. 



The experiment started October 23, 1880 and continued until 

 May 7. 1 88 1. 



In Dr. Siemens's paper, "Some applications of electric energy 

 to Horticulture and Agricultural purposes," presented before the 

 Royal Horticultural Society of London, reports that the electric 

 light was capable of producing upon plants effects comparable 

 to those of solar radiation. It further states that chlorophyll 

 was produced by artificial light, and that bloom and fruit rich in 

 color and aroma could be developed by its aid. Dr. Siemens 

 claims that his experiment went on to prove that plants do not as 

 a rule require a period of rest during the twenty-four hours of the 

 day, but make increased and vigorous progress if subjected (in 

 winter) to solar light during the night. 



These experiments were carried on during six days of the week 

 and not on Sunday. The plants used were peas, Erench beans, 

 wheat, barley and oats, cauliflower, strawberries, raspberries, 

 peaches, tomatoes, and vine crops. Various flowering plants were 

 tested including roses, rhododendrons and azaleas. 



It is interesting to contrast the following data tabulated by Dr. 

 Siemens in 1880-81 with the present day reports. 



( 1 ) One pot : In the dark — Plant became pale yellow and 

 soon died 



(2) One pot: Electric light only — Plant not healthy, pale 

 green. 



(3) One pot: Daylight only — Plant deep green and vigorous. 



(4) One pot : Daylight plus six hours of electric light — 

 Plant superior in vigor, leaf dark rich green. 



29 



