100 



GERMINATION OF SEEDS: SEEDLINGS 



greater the number of lots tested, the more the results will be 

 checked and, accordingly, the safer will be the conclusions. 



In estimating the germinative capacity of seeds, the time 

 allowed for germination must be considered; for seeds having 

 weak embryos and, therefore, unfit for planting may give a high 

 percentage of germination if allowed enough time. It is, there- 

 fore, necessary to fix a time 

 limit, and in doing so the ger- 

 minative speed characteristic 

 of the type of seeds involved 

 and the temperature of the 

 germinator must be consid- 

 ered ; for some seeds naturally 

 germinate more slowly than 

 others, and the effects of low 

 and high temperatures on ger- 

 mination are already known 

 to the student (page 90). 

 Furthermore, kinds of seeds 

 differ so much in germinative 

 capacity that a percentage of 

 germination considered good for one kind of seeds would be con- 

 sidered poor for another. Thus 70 per cent germination is good 

 for Parsnip seeds but very poor for Wheat or Corn. In the 

 following table 1 the number of days in which the seeds should 

 germinate enough to show their germinative capacity, and the 

 percentages of germination considered good for first-class fresh 

 seeds, one year with another, are given. 



FIG. 94. Simple germinator. A, 

 closed. B, open. After F. H. Hillman. 



1 Testing Farm Seeds in the Home and in the Rural Schools. Farmers' 

 Bulletin 428, U. S. Dept. of Agriculture. 



