6 Diseases of Greenhouse Crops 



found that the use of nitrogen and acid phosphate 

 caused an increase in the quantity and quality of the 

 blossoms, but that the excessive use of potassium 

 sulphate and dried blood would act injuriously on 

 the plants. In his work on roses, Muncic * conclud- 

 ed that nitrogen in the form of farm manure, liquid 

 manure or blood is very beneficial. The same seems 

 also to be true for acid phosphate when used at the 

 rate of 4 to 8 tons per acre. Lime should be added 

 only when necessary to sweeten the soil. In this case, 

 finely ground limestone may be used as a top dress- 

 ing at the rate of 10 pounds per 100 square feet of 

 bench space. 



From the above discussion, it is evident that the 

 proper handling of fertilizers underlies the success 

 or failure of greenhouse crops. The cattleman, the 

 poultryman, and others who deal with live stock 

 now fully appreciate the importance of a properly 

 balanced ration. Plants are similarly living organ- 

 isms and consequently they too derive most benefit 

 from a balanced ration (fig. 1, A.). 



Aside from a consideration of the relation of the 

 fertilizer to plant growth, its relationship to the 

 soil must not be overlooked. Certain fertilizers, 

 such as nitrate of soda, yield a residue of sodium, 

 the accumulation of which sweetens the soil, and in 

 the long run makes it alkaline. In clay soils serious 

 physical effects may be the consequence. On the 

 other hand, muriate and sulphate of potash, and 

 sulphate of ammonia leave an acid residuum, the 



*Muncie, F. W., Illinois Agr. Expt. Sta. Bui. 196: 5x1-5(4, (917. 



