72 SEEDS AND FRUITS 



stood. Some seeds may retain their vitality for centuries, but 

 most seeds lose it in a few years. The length of time during which 

 seeds retain their vitality is called their longevity. Most agri- 

 cultural seeds can be stored two or three years without much loss 

 of vitality, and some, when stored a much longer period, may 

 contain a large number of Uve seeds. One investigator found 

 that 50 per cent of samples of Red Clover seeds germinated after 

 being stored in bottles for 12 years; and in samples of the seeds 

 of Pigweed, Sheep Sorrel, Black Mustard, and Pepper Grass, 

 stored in the same way, a large percentage germinated after a 

 storage of 25 years. In samples of White Sweet Clover seeds, 

 which have well modified seed coats, 18 per cent have germinated 

 after a storage of 50 years. There is good evidence that some 

 of the leguminous seeds may retain their vitality for more than 

 a century. Many of the weed seeds when buried in the soil can 

 retain their vitality for many years and then germinate when 

 conditions become favorable. 



The longevity of seeds depends so much upon the conditions 

 under which the seeds were grown, maturity when collected, and 

 methods of storing, that statements as to how old any kind of 

 seeds may be and still be safe for planting are not reliable. Old 

 seeds are often preferable to new ones grown under unfavorable 

 conditions. Seeds from poorly developed plants, although sim- 

 ilar in appearance to those produced under favorable conditions 

 and giving a high percentage of germination soon after harvest, 

 decline rapidly in vitality, often being worthless at the next plant- 

 ing season. For example. Cabbage seeds eight years old may 

 germinate 70 or 80 per cent, while some only three years of age 

 but grown in an unfavorable year may germinate less than 40 

 per cent. Seeds collected green may germinate well after proper 

 curing but they have a short longevity. 



The longevity of seeds depends probably more upon dryness 

 than any other factor. For this reason the place of storage 

 should be dry and the seeds should be cured before they are 

 stored by placing them in a dry airy place. Experiments show 

 that Corn collected soon after maturity and properly cured and 

 stored gives a much higher percentage of germination the next 

 season than Corn allowed to stand in the shock, or taken from the 

 crib. Comparative ' germinative tests of seeds stored in different 

 ' Bulletin 58, Bureau of Plant Industry, U. S. Dept. of Agriculture. 



