How to Grow Plants from Seeds 167 
germinating the seeds of various garden crops differ very 
widely. 
Seeds of a cool-season crop, like mustard and cabbage, 
will often germinate well at temperatures as low as 32° 
to 38° F.; but the best temperature for their germina- 
tion is about 60° to 80°. On the other hand, seed of 
melons will usually not germinate at all if the tempera- 
ture is below 55°; the best temperature for their germi- 
nation is somewhere between go° and 100°. 
Germination is most rapid at the more favorable 
temperatures. Thus muskmelons require 12 days to 
germinate with a soil temperature of 60°, but will germi- 
nate in 48 hours with a soil temperature of 88°. This 
shows clearly why nothing is to be gained by planting 
seeds of the warm-season crops while the soil is yet cold. 
If the soil temperature is too low, germination will not 
take place at all and the seed may decay. 
It is an interesting fact that many seeds will germi- 
nate well at somewhat lower temperatures than is most 
favorable for the later growth and development of the 
plant. The garden mustard germinates at only a little 
above the freezing point; but by the time the seedlings 
have become established, spring is more advanced, the 
air and the soil are warmer, and the temperatures and 
hours of sunlight are more nearly those required for 
vigorous growth. The natural conditions prevailing in 
spring and in summer are hence quite normal for the 
changing needs of the plant. 
The differences between the best temperatures for 
germination and for growth are least for warm-season 
crops. The seeds of melons germinate best at go°, which 
