1 8 PLANT PROPAGATION 



B. The most important factors that determine vitality are ma- 

 turity, harvest weather conditions and ways of harvesting and 

 curing. 



C. Immature seeds soon after ripening usually sprout well, but if 

 stored lose vitality rapidly; well-matured seeds harvested under 

 favorable conditions should keep long. 



D. Seeds harvested in damp weather have less vitality than those 

 harvested in dry weather. 



E. Seeds once injured never regain full vigor. 



F. While proper curing is of the utmost importance, great care 

 is needed to prevent heating, since this reduces vitality. 



FIG. 14 SEED AND BULB DRYING SHED 

 Temporary poles and racks are placed on the permanent poles 



G. The life of seed varies with the family, genera and species ; but 

 there is no relation between the longevity of plants and the viable 

 period of the seed they produce. Some seeds lose their vitality in a 

 few weeks or months [California poppy], others live for years 

 [melons, cucumbers]. 



H. With special precautions the life of seeds may be lengthened 

 within reasonable limits. 



I. Certain seeds retain their vitality better in some sections than 

 in others ; i. e., climate plays an important part. 



J. Moisture is the chief factor in determining the longevity of 

 seeds under cor^nercial conditions. 



K. The bad effects of moisture are heightened where the tem- 

 perature is high. Often vitality is destroyed in a few weeks or 



