362 



Glass 



when the temperature is low and ventilation cannot be 

 given. As the plants grow, more and more ventilation 

 should be given until finally in sunny days the sash may 

 be stripped from the frames. In this way the plants be- 

 come accustomed to the lower temperature and to nor- 

 mal conditions of the atmosphere; they become "hard- 

 ened." Careful attention to ventilation is one of the 

 important means of making plants stocky. 



Hardening-ojf is also promoted by giving the plants 

 plenty of room. As soon as they begin to crowd, some 

 of them may be pulled out, or better, all of them may be 

 transplanted. At the transplanting, it may be well to 

 transfer the plants to a somewhat cooler and more airy 

 frame. With celery and some other plants, it is often 

 allowable to shear the tops, cutting off a fourth or a 

 fifth of the length of the plant to make it branch and 

 thicken. Plants grown in pots, berry boxes, oyster buck- 

 ets are likely to be more stocky than those grown directly 

 in the soil of the hotl)ed, since they have more room; 

 and such plants may not need transplanting. If it is 

 found that the heat is failing, it will be necessary to 

 harden-off the plants more rapidly. 



Certain plants, of which lettuce, cabbage and cauliflower 

 are common examples, can be so completely hardened-off 

 as to withstand considerable frost; and in this toughened 

 condition they may be carried over two or three weeks of 

 cold weather before it is safe to transplant them into the 

 open. The general tendency is to do little transplanting in 

 the frames because of the high price of labor, but trans- 

 planting is always advantageous to the plants, particu- 

 larly if they are started very early. 



