CJIAPTER V'il 



BOTTOM HEAT 



132. Bottom heat is the heat applied beneath the grow- 

 ing plants by means of fermenting material (manure, 

 spent tan bark, brewers' grains, etc.) by warm flues, hot 

 water or steam. It is used more or less for all kinds of 

 seeds started in advance of the outdoor season, espe- 

 cially for those of warm climate plants, but only seeds of 

 certain tropical plants require high heat to germinate. 

 Most garden seeds do not need bottom heat, though many 

 sprout quicker if warmed from below ; always when 

 bottom heat is used the seedlings should be removed to 

 cooler places very soon or they will become "leggy" ; 

 i. e., tall, spindling, and weak. Good ventilation by daj^ 

 will help make them "stock}-" and strong. 



FIG. 74— STRAW MAT FOR COVERING HOTBEDS AND COLD FRAMES 



8G 



