286 VEGETABLE FORCING 







ture on cloudy days during the winter should be about 70 

 degrees. In warm, bright, sunny weather, no injury will 

 result from very high temperatures. It is a common 

 occurrence for the temperature to rise in the houses to 

 over 100 degrees during the months of June and July. 



Ventilation. As previously stated (page 166), the 

 houses should be ventilated as freely as weather condi- 

 tions will permit. Some fresh air should be admitted 

 every day, even in the coldest weather. In warm 

 weather it is desirable to keep the ventilators open all 

 night. During the late spring and summer months doors 

 and ventilators should be opened full width unless 

 storms make it necessary to close them for a short time. 

 Thorough ventilation is exceedingly important in the 

 control of fungous diseases. It is also an aid in the 

 pollination of the flowers. 



Cultivation. When the beds are not mulched it is im- 

 portant to cultivate the soil as often as may be necessary 

 to keep the surface in a loose, friable condition. When 

 2*/2 feet or more of space is allowed between rows, it is 

 possible to till the soil with a wheel hoe. Tillage must 

 not be deep enough to injure the roots of the plants. 



Mulching. The majority of greenhouse growers of 

 tomatoes mulch the beds with horse manure. Among the 

 advantages which may be mentioned are the conserva- 

 tion of soil moisture, prevention of weed growth, saving 

 of labor in cultivating, saving of labor in watering so 

 frequently, and the feeding of the plants by food leached 

 from the manure after every surface application of water. 

 Unless the soil is excessively rich in nitrogen, mulching 

 with manure is probably always beneficial, and should 

 there be a surplus of this element in the soil, cut straw 

 might be substituted. 



Mulching is most beneficial when surface watering is 

 practiced, but it is also an advantage with sub-irrigation. 

 Almost any kind of organic material may be used for 



