76 VEGETABLE FORCING 



large, flat piles 4 or 5 feet deep and with perpendicular 

 sides. If the sides are built up straight, there will be 

 practically no leaching. Water is applied to the manure 

 as often as is necessary to prevent fire fanging. There 

 can be no leaching in the interior of the pile, because no 

 rainfall is ever heavy enough to percolate through 4 feet 

 of manure. The piles should be turned once or twice 

 during the process of decay to assist decomposition and 

 to secure a product of finer texture. Railroad sidings 

 have been constructed at some of the largest establish- 

 ments so that the manure may be thrown on the compost 

 piles without the expense of hauling on wagons. In 

 other instances partly decayed manure is thrown from 

 the cars through side openings of the greenhouse. 



Practically all growers apply the manure in August or 

 September before the work of sterilization begins. A 

 very successful grower at Erie, Pa., has been spreading 

 short, fresh horse manure immediately after the harvest 

 of tomatoes and cucumbers, and this is usually from 

 August 1 to 15. The soil is then plowed, limed, harrowed 

 and watered. Repeated tillage and watering during the 

 summer seem to have a most beneficial effect by destroy- 

 ing weeds and disease germs, and these operations leave 

 the soil in excellent physical and chemical condition for 

 the fall and winter crops. With this plan of soil manipu- 

 lation diseases did not appear for many years, although 

 steam sterilization is now practiced in these houses, but 

 more as a matter of insurance against loss than from any 

 knowledge of serious infection by disease. 



Drying greenhouse soils. In hundreds of small green- 

 houses the soil is permitted to become very dry during 

 the summer months when the houses are not in use. 

 The desiccation is particularly rapid and complete when 

 the soil is on raised benches. A house temperature of 100 

 degrees or more is an almost daily occurrence, and under 

 such conditions only a few days are required for the soil 



