CHAPTER XI 

 CONSTRUCTION OF HOTBEDS 



152. The necessity of glass. In nearly all types of 

 vegetable gardening glass is essential to secure the best 

 returns. It is true that many crops, as sweet corn, cab- 

 bage, peas, beans and the root crops, are grown at a 

 profit without the use of glass, although most gardeners 

 regard it as indispensable for certain parts of their opera- 

 tions. The term glass includes the different types of hot- 

 beds, cold frames, forcing hills and greenhouses. 



Glass is often used merely for protection, as for winter- 

 ing plants in cold frames. The more common uses, 

 however, are to hasten or forward the growth of plants, 

 so the crops will mature before their normal time, and to 

 grow crops to full maturity during the winter season, 

 when it is not possible to produce them in the open in 

 the same latitude. 



There are many advantages in starting certain vege- 

 tables under glass, then transplanting to the open ground 

 as soon as conditions are right. Some of these advan- 

 tages are: (i) Crops placed on the market before their 

 normal season usually command the highest prices. (2) 

 In many sections the summers are too short to mature 

 certain crops, such as eggplants, watermelons and late 

 tomatoes, without the use of glass. (3) In starting the 

 crop early there is less danger of loss by destructive 

 frosts in the fall. (4) By forwarding the plants under 

 glass, two or more crops can often be grown on the same 

 land during the season. (5) Weeds are generally less 

 difficult to combat when plants of good size are Set in the 

 open. (6) It may also be the means of avoiding trouble- 

 some insects and fungous diseases. (7) Some vegetables, 



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