HOTBEDS AND COLD FRAMES 93 



In purchasing or constructing sash the most dur- 

 able woods should be secured, cedar or cypress 

 being preferred. White pine is often used, but does 

 not last as well as the above woods and begins to 

 loosen and rack earlier, causing considerable loss 

 from the breaking of glass. The sash should be 

 kept well painted and when properly stored and 

 handled will last for many years. 



Both single and double-glazed sash are upon the 

 market and both have their advantages and disad- 

 vantages. Double-glazed sash reduce the labor of 

 managing the frames and permit the plants to re- 

 ceive the light during the entire day. On the other 

 hand, double sash are much heavier to handle, which 

 becomes a serious objection when large numbers of 

 them are used. The cost is from one-third to one- 

 half more for the double glazed. The mois- 

 ture and dirt accumulate between the glass of the 

 double glazed, thus greatly reducing the amount of 

 light entering the frames, which results in poor 

 growth. In general, it may be said that where a 

 few sash only are required double glazed will prob- 

 ably give the best results, but where large numbers 

 are used single glazed will be more satisfactory. 



When manure is used as a source of heat, an 

 excavation is usually necessary to receive it, and 

 the first essential at this point is good drainage, 

 either natural through a gravelly subsoil or arti- 

 ficial. The pit should be dug in the fall before the 

 ground is frozen and a few inches of leaves or 

 strawy manure placed in the bottom. It should be 

 the same width as the frame and of any desired 

 length, but usually some multiple of three. The 

 depth of the pit will vary with the latitude and the 

 part of the season through which it is expected to 



