Varied opinions have been given as to the duration of vitality of seeds of the cultivated plants. This largely comes from the varied modes of drying and storing of seeds. As an instance, onion and other seeds are often sunk in water to clean, as the chaff rises to the surface. Such seed is only good for one year as a rule. But onion-seed properly handled is good for ten years or more. As a rule, the vitality of all seed is reduced by age. Some seeds with the best care rarely germinate when more than one year old, and the fruit-tree seeds kept dry for one year are much lowered in vitality. Tables are often compiled giving the extreme duration of seeds under proper conditions. But they are so unsafe, on account of varying conditions, that the certain rule is to plant seeds the season following their gathering. The only exceptions are possibly with melons, cucumbers, squashes, and some other plants noted for excessive vigor of growth. It is claimed in such cases that seed three or four years old gives less growth and more fruit than the new seed.
Fig. 3. - Lath-covered Shed for Seed-beds. (After Bailey.)