36 METHOD OF CULTIVATION. 
spring when the seed is capable of being awaked into life. 
The germination of the seed of all plants in the open 
ground, uniformly occurs in the spring, at a certain point 
of temperature, which is the same for all plants of the same 
species, but differs with the species. The degree of mean 
temperature which determines the germination of the seed 
of sorghum is generally reached early in the month of 
April, in the climate of the Middle States, and if the soil 
has been suitably prepared, the young plant will continue 
to grow from that time forward. Growth is maintained 
under conditions which would be ruinous to Indian-corn, 
yet, reasoning from a false analogy, we have been in the 
habit of planting cane at a season when, if the true habits 
of the plant had been regarded, the larger part of the 
most critical and extended period of its growth would 
already have elapsed. 
By early spring planting its demands for a large exten- 
sion of the root are complied with, forin the low tempera- 
ture prevalent then only, can that full measure of vital 
energy be concentrated in the root, which is afterward so 
essential to the rapid and perfect development of the stalk. 
If the early stage of its life is passed during that time, it 
will be prepared to receive at the time of “shooting,” when 
it needs it, the sudden accession of heat which gives to our 
later spring the character, as to temperature, of an English 
midsummer. 
In the latitude of Philadelphia, 40°5° and 62°. Fahr. 
are the measures of average daily temperature, which are 
assumed as the limits defining the beginning and end of 
the meteorological spring—or the season of leaf expan- 
sion in general—commencing with the swelling of the buds, 
and the first signs of active vegetation, and ending with 
the full expansion of the foliage. It includes a period of 
about sixty-five days, or from the 15th of March to the 
