342 Report of the Horticultural DErARTMiENT of thb> 



thoroughlv mixing returniDg it to the same bos. The quantities 

 of manm*e were reduced from 5 i)er ct., 10 per ct., 15 per ct., or 

 20 per ct. by weight, to 5 per ct., 10 per ct., 15 per ct., or 20 per 

 ct. by bulk, respectively. See Table II. This made the actual 

 amount considerably smaller than that given to the same box 

 for the previous year. So far as influencing the experiment 

 is concerned, it need only be said that the relative amounts 

 added to the different series remain the same. Moreover, the 

 composition of the manure varied in the different seasons. The 

 total amount added to any particular box may be easily calcu- 

 lated. In experiments of this kind the exact amount of plant- 

 food available to each plant or set of plants cannot be accurately 

 determined. All that is expected is to know the kind, relative 

 amounts and composition of the plant-food which is added to the 

 various portions of soil under experiment. 



A further change consisted in the use of a loose lettuce, the 

 Grand Rapids, in addition to the Rawson Hothouse head lettuce, 

 two plants of each variety being grown in each box. 



The seed was planted Oct. 7, in the same manner as before. 

 Germination began to appear Oct. 13. The loose lettuce was all 

 cut Jan. 15 and 16. The crop could not be held longer without 

 having the most advanced plants begin to deteriorate. 



The head lettuce was harvested Jan. 30. It was not then 

 mature; but for lack of strict attention to ventilation and water- 

 ing during a period of sunshine following dull weather, tipburn 

 had made its appearance. The crop was at once harvested for 

 fear that rot might follow the tipburn and vitiate the results 

 of the work. 



Some of the facts established both by observation of the grow- 

 ing plants and by the weights of the different yields are given 

 in the following statements: 



As to the effect of commercial fertilizers when used without 

 manure, the nitrate of soda gave best results on the clay loam. 

 Sulph.'ite of ammonia gave much the best results with loose let- 

 tuce on the sandy loam and was unsurpassed with the head 

 k'ttuce. It should be noticed, however, that this was an excep- 



