7« 



HATCH EXPERIMENT STATION. 



[Jan. 



Table showing Difference in Lettuce Plants grown in Sterilized 



and Unsterilized Soil. 



The average weight of the largest plants represented that 

 taken from four specimens selected from each bed in corre- 

 sponding rows and close proximity. The four typical plants 

 from each bed were selected at random, and they happen 

 to show the same relative weight to each other as the largest 

 ones do. The weights were all taken when the crop was 

 four weeks along in the house and the treated ones were 

 nearly ready for marketing. The plants were selected and 

 weighed, and the amount of water determined in each lot, 

 by Mr. A. L. Dacy, a student of the present senior class, 

 who had charge of the house and who was quite familiar 

 with the crop. The per cent, gain by starting the seed in 

 sterilized soil and also transplanting the prickers in simi- 

 larly treated soil, then transplanting into soil treated with 

 hot water, was 33 per cent., which is a fair average increase 

 due to this method of treatment. 



The writer has made comparisons of lettuce plants grown 

 in a rather poor quality of soil, one lot being sterilized and 

 the other treated with the best possible combination of 

 commercial fertilizers, with the result that the sterilized 

 plants compare most favorably with those treated with 

 fertilizers. This does not imply that sterilization will nec- 

 essarily dispense with the use of fertilizers in the lettuce 

 crop, if one wishes to apply them ; as a matter of fact, 

 however, they are seldom employed. The lettuce plant 

 requires an exceedingly large amount of organic matter in 

 the soil, and for this reason a generous supply of Avell- 

 rottcd horse manure is continually employed, for the double 

 purpose of supplying organic matter and plant food. Plants 



