Germination 



autumn. Above or below this limit germina- 

 tion will slacken, or cease altogether if the 

 divergence is too great. 



The help of air is no less indispensable. 

 It would be of no use to submit the seeds 

 to a suitable temperature and moisture ; if 

 air is lacking there will be no germination. 

 This primary condition explains why seeds 

 that are buried too deeply will not come up ; 

 why germination is much easier in ground 

 that is light and permeable by air, than in 

 that which is more compact ; why delicate 

 seeds should be covered very slightly with 

 earth, or only scattered on the surface of the 

 damp ground ; and why ground that is 

 turned over is sometimes covered with new 

 vegetation, resulting from seeds that for 

 long years have been sleeping inactively and 

 that the air has caused to germinate when 

 our excavation has brought them from the 

 depth to the surface. 



With the same conditions of temperature, 

 moisture and air, all seeds by no means 

 take the same time to germinate. Cress 

 will generally germinate in two days. The 

 parsnip, turnip and bean take three days to 

 come up ; lettuce, four ; the melon and pump- 

 kin, five ; and cereals about a week. The 



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