How to Grow Plants from Seeds 185 



the sash at the height desired. If the weather suddenly 

 becomes cold or cloudy, the sash should be shut down. 



In extremely cold weather, and especially at night, 

 the sash may be covered with straw, blankets, old carpet, 

 or the matting which is made for this use. As spring 

 advances, the sash may be raised higher and for longer 

 periods during the day, until finally they may be re- 

 moved, to be replaced only on cool nights. 



At the time seedlings burst from the soil they may be 

 somewhat " burned " by midday sunshine. This may be 

 prevented by spreading a single sheet of newspaper over 

 them during the middle of the day for a day or two. 

 Freshly transplanted seedlings should thus be shaded. 

 Plants standing in the middle of the frame will receive 

 more light than those at the edge ; so it is a good plan 

 to shift and turn the flats from time to time. Usually 

 the growing plants are given all the sunlight that is 

 available. 



After it is properly started, only a few minutes are 

 required each day to care for the hotbed ; but daily 

 attention and management, according to changing 

 weather, is absolutely necessary for the best results. 



Construction and use of a cold frame. A cold frame 

 consists of a frame with a sash or cloth covering. It is 

 usually placed directly on the ground. No artificial heat 

 is supplied as in the hotbed, but the frame affords pro- 

 tection from the cold air of the outside. The covering of 

 sash or cloth helps to retain over night the heat received 

 from the sun during the day. 



Cold frames are especially useful for hardening seed- 

 lings previously grown in a hotbed. This is done by 



