396 VEGETABLE FORCING 



may be necessary. As a rule, the opening is made on the 

 side away from the wind, so that the wind will not blow 

 into the frame. If only a small amount of ventilation is 

 needed, every other or perhaps every third or fourth sash, 

 moved only an inch or two, will admit sufficient air. 



When there are no cross bars, blocks of wood may be 

 placed under the ends of the sash or at some distance 

 from the ends of them, as shown in Fig. 138. This system 

 is somewhat objectionable on account of its tendency to 

 warp the sash. In warm, sunny weather the sash may 

 be entirely removed during the day and replaced on the 

 frames in the evening. A careful study of the appearance 

 of the plants will enable the gardener to determine 

 whether they are being properly ventilated. 



Cloth covers are removed from the frames whenever 

 the weather will permit. While they conserve heat they 

 also exclude sunlight, and if they are kept on too much 

 of the time the plants will become weak and spindling 

 and subject to disease. 



Control of pests. For methods of controlling various 

 insect and fungous enemies, see Chapters VII and VIII, 

 and notes on different classes of vegetables. 



VEGETABLES GROWN IN FRAMES 

 Asparagus may be forced at any time during the winter 

 in heated frames. The roots from which the shoots are 

 to be grown are dug late in the fall and stored in a cool, 

 moist place until wanted for use. The details of culture 

 are essentially the same as when the crop is forced in the 

 greenhouse. See Chapter XII for particulars. 



Bean. This vegetable is sometimes grown in frames 

 as a spring crop. The covering of cloth or glass should 

 be used for about a month, or longer in the coldest sec- 

 tions, and then no further protection need be given. An 

 excellent plan is to plant bush beans at proper intervals, 

 in rows not less than 22 inches apart, between rows of 



