192 MINNESOTA. STATE HORTICULTURAL SOCIETY. 



their being the first successful applications of the electricity to commer- 

 cial plant growing. The following is a description of his methods of work 

 and the results; 



Thirteen houses are devoted to lettuce and one of them covers nearly 

 one-third of an acre. This great house was built last year at an expense 

 of $5,000: it is so large that the ground inside is plowed with steam, it is 

 33 by 370 feet in outside dimensions, 15 feet to the ridge, 3i feet high on 

 the south or lower side and 12 feet on the north side. From this house 

 Mr. Rawson takes at one crop 2,000 dozen heads of lettuce, and the heads 

 are twice the size of those which wc ordinarily see on the market. He 

 was, probably, the first to use the electric light for the commercial grow- 

 ing of plants. His attention was called to the subject by observing the 

 beneficial effects of street lamps which hung near his houses. He now 

 runs three 2,000 candle-power arc lights all night throughout the winter 

 for the sole purpose of hastening the growth of lettuce. Mr. Rawson de- 

 clares that these lights hasten the maturity of lettuce by 10 per cent.; and 

 says that the gain produced upon one crop pays for the running of the 

 lamps for the entire winter. He calculates that there is an average gain 

 of five days for each crop, or a total saving of fifteen days for the entire' 

 winter. He also says that the plants head up better under the light and 

 that the quality is superior. The effect of the light is marked at a dis- 

 tance of 100 feet from the lamp. 



