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UNIV. OF N. H. AGR. EXPERIMENT STATION [Bulletin 250 



GROWING HEAD LETTUCE IN NEW HAMPSHIRE 



Iceberg lettuce grown on experimental plots at Lancaster succeeded, 

 while the crops at Colebrook failed, in tests by A. H. Watson of the feasi- 

 bility of producing sohd head lettuce during the summer months under the 

 cool climatic conditions prevailing in northern New Hampshire. 



The failure of the crop at Colebrook may have been due to unfavorable 

 climatic conditions of temperature and humidity, or to an unsuitable soil. 

 The troubles encountered at Colebrook are believed in the western lettuce- 

 growing sections to be caused by high night temperatures. The maxi- 

 mum night temperature at Colebrook, however, in 1929 was 68 degrees 

 F., which is probably well within the limit of safety. 



Figure 5. — One of the plots at Lancaster where the practicability of raising iceberg 



lettuce is being tested. 



At Lancaster on the several plots from 15 to 46 per cent of solid heads 

 were harvested, and the average proportion of solid heads indicates the 

 possibility of a yield of 125 crates of four dozen heads to the acre. 



Arrangements had been made at Lancaster to determine the necessity 

 and desirability of irrigating the lettuce crop. The rainfall during the 

 one-hundred day period from May 21 to September 1 was 11.48 inches and 

 reasonably well distributed. The irrigation plant under these conditions 

 was used infrequently and the most water applied to any plot was two 

 inches. 



