212 VEGETABLE FORCING 



for adding other fertilizing materials. In fact, the results 

 of hundreds of growers might be cited in support of this 

 view. 



It is claimed by some growers, especially by those who 

 are cultivating light soils, that the free and continued 

 use of stable manure ultimately makes the soil too open 

 and porous for the best results with lettuce, and that it 

 is preferable to use less manure, and to supplement it with 

 commercial fertilizers. This class of growers, however, is 

 in the minority, though there are some who obtain ex- 

 cellent results from the applications of commercial ferti- 

 lizers in connection with manure. Rules cannot be made 

 regarding the use of stable manures in greenhouses be- 

 cause conditions of soils, supply and kinds of manures 

 available, treatment of previous crops, kind of crop to 

 follow, etc., are so variable that no one treatment will 

 suit all conditions. 



The use of commercial fertilizer in growing lettuce 

 under glass was advocated by Thorne of Wooster, Ohio. 

 He found that a home mixture of 20 pounds of nitrate of 

 soda, 60 pounds acid phosphate and 20 pounds muriate of 

 potash, applied in judicious amounts with moderate 

 applications of manure, increased the yields. 



Nitrate of soda is frequently applied to lettuce under 

 glass. Sometimes the crop does not make as rapid growth 

 as is desired; then a light application of nitrate of soda 

 may have a very beneficial effect. As explained before, 

 it may be used in liquid form, the plants even being 

 sprayed with a dilute solution that will not burn them, 

 the solution to be washed from the plants with a spray 

 of pure water. 



When nitrate of soda is mixed with the soil before the 

 lettuce is planted, one pound to 100 square feet of space 

 will be as much as can be used with safety to the plants. 



A practice which is increasing among farmers, and 

 there is no reason why it should not be just as valuable 

 for greenhouse vegetable growers, is to mix acid phos- 



