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 90 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 90, which 



