26 Principles of Plant Culture. 



at which they can germinate. The following table* 

 shows approximately the minimum, optimum and maxi- 

 mum temperatures at which seeds of the species named 

 germinate. 



MINIMUM. OPTIMUM. MAXIMUM. 



Barley 41 F 77-88 F 99-lll F. 



Bean (Scarlet runner).... 41 77-88 88-99 



Buckwheat 41 93 115 



Clover (red) 88-99 99 -111 Ill -122 



Cucumber 60-65 88 -99 Ill -122 



Flax 41 77 -88 88 -99 



Hemp 32-41 99-111 Ill -122 



Indian corn 41-51 99 -111 Ill -122 



Lucern (Alfalfa) 88-99 99 -111 Ill -122 



Melon 60-65 88 -99 Ill -122 



Oat 32-41 77 -88 88 -99 



Pea 32^11 77 -88 88 -99 



Pumpkin 51-60 93 -111 Ill -122 



Rye 32-41 77 -88 88 -99 



Sunflower 41-51 88 -99 99 -111 



Wheat 32-41 77 -88 88 -108 



These temperatures refer to the soil or other medium 

 with which the seeds are in contact, and not to the 

 atmosphere. 



When moisture is sufficient, the time from planting to 

 sprouting decreases rapidly as we approach the optimum 

 temperature. In an experiment, Indian corn sprouted 

 in one- third of the time at 88 F. that it required to 

 sprout at 61. 



31. Free Oxygen is Essential to Germination. If we place 

 in the bottom of each of two saucersf a layer of puddled J 



* Compiled from Haberlandt and Sachs. 



f If flower-pot saucers are used they should first be well soaked in 

 water, so that they will not extract water from the soil. 



t Soil is said to be puddled when wet and packed until it is in the con- 

 sistency of putty. 



