52 MANAGEMENT OF THE FORCING-HOUSE. 



changed rarely long remain free of serious insect or fun- 

 gous invasions ; and in selecting soils for houses, it is of 

 the utmost importance to avoid bringing in grubs, cut- 

 worms, wire-worms, tomato rust, and the like. It is per- 

 fectly possible to add plant food to the old soil, but it is 

 impossible to restore its texture by that means, and the 

 physical texture is usually more important than its actual 

 store of food. In the forcing of lettuce upon ground 

 beds, it is not always essential to remove the earth every 

 year, although an inch or two of the top must be re- 

 moved if the mildew has been serious, and the soil should 

 always be fertilized before another season of forcing is 

 begun. The best growers prefer, however, to replace 

 four or five inches of the top soil every summer. 



THK QUESTION OF FERTILIZERS. 



Most forcing-house crops need to be fertilized as they 

 grow. This is particularly important for tomatoes, cucum- 

 bers and melons. The fertilizer most liked by gardeners 

 is liquid manure. This is made from old un leached cow 

 manure (such as has been lying for some months in a barn 

 basement). A bushel of it is placed in a half-barrel or tub 

 and the receptacle is filled with water. After standing two 

 or three days, being stirred occasionally in the meantime, 

 the liquid is ready for use. This liquid must be reduced 

 before it is applied to soil in which plants are growing, and 

 the amount of reduction to give it can be determined only 

 by experience. Ordinarily, one quart of liquid made as 

 here directed will be sufficient for a gallon of the diluted 

 material ; that is, one quart of the manure water is added 

 to three quarts of clear water. If the manure is strong, 

 the tub may be filled with water three or four times before 

 the strength of the material is dissolved out. A tub of this 

 manure liquid should always be accessible in forcing-house 

 work. How often the liquid shall be applied to the crops 

 must be determined for each particular case. If the soil is 



