416 VEGETABLE FORCING 
make arrangements with manufacturers several months 
in advance of the date when it will be wanted for plant- 
ing. But it is safer to have delivery arranged for only a 
few weeks before the beds are spawned in order to avoid 
storage risks. 
Spawning the beds.—As previously stated, a tempera- 
ture of about 70 degrees, which may be determined by a 
thermometer plunged into the manure, is probably best 
for the spawning of the beds, though this is often done at 
temperatures ranging from 10 to 15 degrees higher. The 
beds may be spawned at 55 to 60 degrees, but the mush- 
rooms will grow much less rapidly if the spawning is 
done at lower temperatures than 55 degrees. 
There are no rules regarding the best distances for in- 
serting the spawn. Ordinarily, a brick is broken into 10 
or 12 pieces, sometimes more, and one piece is considered 
sufficient for about a square foot of bed. The pieces may 
be planted in check rows a foot apart, or at closer inter- 
vals if desired. A little manure is raised and a hole made 
where each piece of spawn is to be inserted; the spawn 
is covered with an inch or two of the manure and pressed 
firmly with the hand. If the bed seems too loose after 
the work of spawning has been completed, the entire 
area may be firmed with a board or a block of wood. 
Casing the beds.—Mushroom beds are always covered 
with an inch or two of fine, rich, moist, loamy soil and 
this operation is termed “casing.” Its purpose is to con- 
serve moisture, give support to the mushrooms and pre- 
sumably to improve the quality of the product. The 
casing is usually placed on the beds in 10 days to two 
weeks from the date of spawning. If conditions have 
been right, the mycelium will then appear as a moldy 
growth on the pieces of spawn. It is an interesting fea- 
ture of mycelium growth that as it runs through the 
manure, the casing acts as a check on vegetative develop- 
ment, thus forcing the reproductive development, and to 
