MAKIXG UP THE MUSHROOM BEDS. 75 



depth is attained. If it is a floor bed and there is no 

 impediment, as a shelf overhead, tread the manure down 

 firmly and evenly; if the manure is fairly dry and in 

 good condition it will be pretty firm and still springy, 

 but if it is too moist and poorly prepared treading will 

 pack it together like wet rotten dung. 



Now pierce a hole in the bed and insert a thermometer. 

 There are "ground" or "bottom-heat" thermometers, 

 as gardeners call them, for this purpose, but any com- 

 mon thermometer will do well enough ; and after two or 

 three days examine this thermometer daily to see what 

 is the temperature of the manure in the bed. In roomy 

 or airy structures or where only a small bed has been 

 made it may, in the meantime, be left in this condition. 

 But in a tight cellar I find that the warm moisture aris- 

 ing from the bed condenses in the atmosphere and settles 

 on the top of the manure, making it perfectly wet. In 

 order to counteract this, as soon as the bed is made up 

 I spread some straw or hay over it loosely ; the moisture 

 settles on the covering and does not reach through to 

 the manure. Beware of overcovei-ing, as such induces 

 overheating inside the bed. At spawning time remove 

 this covering. The bed will then have become so cool 

 (80° or 90°) that there is very little evaporation from it, 

 consequently little danger of surface-wetting. 



The Proper Temperature. — This, in mushroom 

 beds, depends upon the materials of which they are com- 

 posed, their thickness, how they are built, the situation 

 they are in. and other circumstances. If the manur3 

 was good and fresh to begin with, carefully prepared 

 and used as soon as ready, the bed in a few days will 

 warm up to 125°, or a little more or less, and this is 

 very good. My best beds have always shown a maxi- 

 mum heat of between 130° and 135°. Had the manure 

 been Used a few days too soon the beat would rise higher, 

 perhaps to 135°, but this is too warm; in this case I 



