Gardeners' Chronicle (of America) 25(9): 709-710 (September, 1921)


It is, of course, a well-known fact that the capacity of seeds to germinate tends to decrease with age. In some cases germination capacity falls off very rapidly: in other cases it remains high for a number of years after the seed has been harvested. Among vegetable-garden crops parsnips afford an example of seeds whose germinating capacity soon deteriorates, even so short a period as one year sufficing to reduce the percentage of germination to a relatively low figure. Plants of the cabbage tribe, turnips, etc., retain their germinating capacity longer, but at the end of two or three years it will be found to have become less than it was in the year of harvesting. The seeds of peas and beans suffer less from the effects of keeping, and may give quite good results after three or more years. Needless to say, the power of seeds to retain their capacity to germinate varies not only with the variety, but also with the nature of the harvest and with the conditions under which the seeds are stored. A poor harvest year generally means in this country one in which seed does not ripen thoroughly; that is, does not dry off completely, and such seed generally shows a relatively low initial power of germination and poor "keeping" properties. Conditions of storage also affect the keeping properties of seed. If the air is either uniformly damp or subject to marked alternations of dampness and dryness, the germinating capacity falls off rapidly. That this is the case may be easily understood when it is remembered that seeds arc very hygroscopic—that is, readily take up water when exposed to a moist atmosphere. It is, therefore, necessary if for any reason it is desired to keep seeds for a long time, to put them in sealed bottles or jars, and to store them in a cool place. So sensitive are the seeds of some plants that even exposure to light may affect their powers of germination. It follows from what has been said that a good general rule is to sow seeds the year after harvesting. This rule, however, is one which admits of numerous exceptions. For instance, some seeds—e.g., primulas—germinate better if sown before they are fully matured than they do if sown after their fruits have completely ripened. On the other hand, it is an old belief that with some plants seeds of more than one year old give better plants than do seeds of the previous harvest. Thus a writer in the Queensland Agricultural Journal (XV, April, 1921) cites the belief often entertained by gardeners that two-year-old seeds of beet and carrot give better plants than are to be obtained from fresh seed. The same writer also states that three-year-old chicory and cabbage seeds should be sown, and that spinach, lettuce, and radish are less apt to bolt if grown from two-year-old seed. For our part we are inclined to be sceptical of the correctness of these opinions, and should certainly prefer to sow one-year-old, i.e., fresh harvested seed, in all these cases. The practice of an earlier race of gardeners of carrying melon seed for a year or so in the waistcoat pocket before sowing may, however, mean that in the case of this plant old seed gives better results than new. Another belief which would seem to be well founded is that the proportion of doubles may be increased in the cases of stocks and asters by sowing old seed. How ancient is this belief is illustrated by a citation, published in the Revue Horticole, from an old garden book of 1765, which runs: "Many amateur and professional gardeners are certain that stock seed kept for five or more years gives a larger percentage of doubles than does fresher seed."—The Gardeners' Chronicle (British).