GLASS STRUCTURES 63 



are excellent places in which to store hardy shrubs be- 

 fore they are forced. A false bottom may be used and 

 the frame is then convenient for storing bulbs in the 

 fall (Fig. 8, upper). 



55. Coldframes. Coldframes may be made with a 

 sub-frame, the same as that described for the hotbed, or 

 they may be made with simply the frame above ground. 

 Frames above ground are usually portable, and may be 

 knocked down easily and the location changed. The only 

 difference between a coldframe and a hotbed is that there 

 is an under layer of fermenting manure in the hotbed, 

 while frames have no artificial heat. Frames are used 

 more particularly for storing hardy species and bulbs; 

 also for giving some protection to plants before they can 

 be planted safely in the open ground. Plants grown in 

 greenhouses may be " hardened off " in coldframes. 

 Hotbeds are started earlier than are coldframes. 



56. Equipment for hotbeds and frames. The material 

 for equipping both frames and hotbeds consists of sashes, 

 mats, board shutters and, in some cases, lath or canvas 

 screens. 



It is usually best to buy the sash. The standard size is 

 three by six feet, and the price varies from 82.75 to $3.50 

 each, according to the durability of the sash and the care 

 with which it is constructed. They should be kept in 

 good repair and painted every year so that the putty will 

 not crack, thus loosening the glass. 



Mats for hotbeds and coldframes may be made of 

 strong burlap lined with waste wool or cotton, and 

 quilted. Mats may also be made of straw or similar 

 material, depending upon the locality. If in the vicinity 

 of hat factories, the matting in which the straw is shipped 

 from foreign countries may be utilized for mats. They 



