484 Report of the Horticulturist of the 



INTRODUCTION. 



Some experiments with the use of commercial fertilizers ia. 

 forcing lettuce were started in the fall of 1896 in connection with 

 the tests of soil mixtures which have been discussed on preceding 

 pages. Four soil mixtures were tried at this time, three of which 

 received acid phosphate, sulphate of potash and stable manure 

 liberally, and in equal quantities, and differed from each other 

 only in the amounts of nitrate of soda which were applied to them. 

 The fourth mixture, Soil 12, received the same amount of stable 

 manure as the others but none of commercial fertilizers, as is 

 shown in the following table : 



Table VI. — Ingredients of Soils Used and Fertilizers Applied in Lettuce 



Forcing. 



Soil 



Ingredients (by weight). Fertilizers applied per acre. 



mixture. Clay Sand Stable Acid Sulphate Nitrate 



loam. manure. phosphate. of potash, of soda. 



Perct. Perct. Perct. Lbs. J bs. Lbs. 



4 52.2 32.3 15.5 600 400 133 1-3 



12 52.2 



13 52.2 



14 52.2 32.3 15.5 400 2G6 2-3 



A head lettuce, Rawson's New Hothouse, grown from purchased 

 seed, was used for these tests. 



After this crop was removed, acid phosphate and sulphate of 

 potash were applied to the soils which had received them before 

 and at the same rate as formerly. All soils were then turned and 

 prepared for another crop. The method of planting the seeds and 

 selecting and managing the plants was the same for all soils as 

 for Soil 4a, Crop III, which have been described on page 470. 



Six weeks after seed planting, when the plants had become well 

 established, nitrate of soda was first applied at the rate of 33 1-3 

 pounds per acre for Soil 4a and 66 2-3 pounds for Soil 14a. Two 

 similar applications followed at intervals of 10 days, making the 



