104 THREE ACRES AND LIBERTY 



Another way that the old gardeners have to make a hot- 

 bed is with fire. On a large scale this is cheaper, though 

 more complicated than the fermentation of manure. In 

 making this kind choose your location and build the frames 

 as before. "Cut a trench with a slight taper from the east 

 end of the plot to the end of the hotbed, and on under the 

 ground to about four feet beyond the end of the bed. This 

 taper to the outlet will create a draught and so keep a better 

 fire. Arch this over with vitrified tile. The furnace end 

 where the fire is should be about six feet away from the bed. 

 When the trenches are completed, cover over with the dirt 

 that was taken out of them. Two such trenches under the 

 frames will make a good hotbed. Any one can do this sort 

 of work." 



A hotbed can also be heated by running steam pipes 

 through the ground, but unless you happen to be where 

 exhaust steam could be used, this method is not economical 

 except for big houses. The care and expense of a separate 

 steam plant would be too great to pay, unless for growing 

 winter vegetables for market or flower culture. If you go 

 into that on a scale large enough to pay, new problems at 

 once demand solution. 



Vegetables under glass have kept pace with other crops. 

 Within fifteen miles of Boston are millions of square feet of 

 glass devoted to vegetables, chiefly lettuce. There are 

 more than five million feet in the United States used for 

 other crops. Ordinarily, under favorable conditions, glass 

 devoted to this work will yield an average of fifty cents 

 per year per square foot. 



About the lowest estimate of cost per sash is five dollars ; 

 this amount includes the cost of one fourth of the frame and 

 covers. There are usually four sashes to one frame. A 



