How Crops Grow, pp. 305-309 (1868)
Samuel William Johnson

Duration of Vitality.—In the mature seed when kept from excess of moisture, the embryo lies dormant. The duration of its vitality is very various. The seeds of the willow, it is asserted, will not grow after having once become dry, but must be sown when fresh; they lose their germinative power in two weeks after ripening.

With regard to the duration of the vitality of the seeds of agricultural plants there is no little conflict of opinion among those who have experimented with them.

The leguminous seeds appear to remain capable of germination during long periods. Girardin sprouted beans that were over a century old. It is said that Grimstone with great pains raised peas from a seed taken from a sealed vase found in the sarcophagus of an Egyptian mummy, presented to the British Museum by Sir G. Wilkinson, and estimated to be near 3,000 years old.

The seeds of wheat usually lose their power of growth after having been kept 3-7 years. Count Sternberg and others are said to have succeeded in germinating wheat taken from an Egyptian mummy, but only after soaking it in oil. Sternberg relates that this ancient wheat manifested no vitality when placed in the soil under ordinary circumstances, nor even when submitted to the action of acids or other substances which gardeners sometimes employ to promote sprouting. Vilmorin, from his own trials, doubts altogether the authenticity of the "mummy wheat."

Dietrich, (Hoff. Jahr., 1862-3, p. 77,) experimented with seeds of wheat, rye, and a species of Bromus, which were 185 years old. Nearly every means reputed to favor germination was employed, but without success. After proper exposure to moisture, the place of the germ was usually found to be occupied by a slimy, putrefying liquid.

The fact appears to be that the circumstances under which the seed is kept greatly influence the duration of its vitality. If seeds, when first gathered, be thoroughly dried, and then sealed up in tight vessels, or otherwise kept out of contact of the air, there is no reason why their vitality should not endure for ages. Oxygen and moisture, not to mention insects, are the agencies that usually put a speedy limit to the duration of the germinative power of seeds.

In agriculture it is a general rule that the newer the seed the better the results of its use. Experiments have proved that the older the seed the more numerous the failures to germinate, and the weaker the plants it produces.

Londet made trials in 1856-7 with seed-wheat of the years 1856, '55, '54, and '53.

The following table exhibits the results, which illustrate the statement just made. 

  Per cent of seeds
Length of leaves
 four days
 after coming up.
Number of stalks
and ears per
hundred seeds.
Seed of 1853, none
   "     "  1854, 51 0.4 to 0.8 inches 269
   "     "  1855, 73 1.2" 365
   "     "  1856, 74 1.6" 404

The results of similar experiments made by Haberlandt on various grains, are contained in the following table:

Per cent of seeds that germinated in 1861 from the years:
  1850 '51 '54 '55 '57 '58 '59 '60
Wheat 0 0 8 4 73 60 84 96
Rye 0 0 0 0 0 0 48 100
Barley 0 0 24 0 480 33 92 89
Oats 60 0 56 48 72 32 20 96
Maize 0 not tried 76 56 not tried 77 100 97

Results of the Use of long-kept Seeds.—The fact that old seeds yield weak plants is taken advantage of by the florist in producing new varieties. It is said that while the one-year-old seeds of Ten-weeks Stocks yield single flowers, those which have been kept four years give mostly double flowers.

In case of melons, the experience of gardeners goes to show that seeds which have been kept several, even seven years, though less certain to come up, yield plants that give the greatest returns of fruit; while plantings of new seeds run excessively to vines.

Unripe Seeds.—Experiments by Lucanus prove that seeds gathered while still unripe,—when the kernel is soft and milky, or, in case of cereals, even before starch has formed, and when the juice of the kernel is like water in appearance,—are nevertheless capable of germination, especially if they be allowed to dry in connection with the stem (after-ripening.) Such immature seeds, however, have less vigorous germinative power than those which are allowed to mature perfectly; when sown, many of them fail to come up, and those which do, yield comparatively weak plants at first and in poor soil give a poorer harvest than well-ripened seed. In rich soil, however, the plants which do appear from unripe seed, may, in time, become as vigorous as any. (Lucanus, Vs. St., IV, p. 253.)

According to Siegert, the sowing of unripe peas tends to produce earlier varieties. Liebig says: "The gardener is aware that the flat and shining seeds in the pod of the Stock Gillyflower will give tall plants with single flowers, while the shriveled seeds will furnish low plants with double flowers throughout."

Dwarfed or Light Seeds.—Dr. Müller, as well as Hellriegel, found that light grain sprouts quicker but yields weaker plants, and is not so sure of germinating as heavy grain.

Baron Liebig asserts (Natural Laws of Husbandry, Am. Ed., 1863, p. 24) that "the strength and number of the roots and leaves formed in the process of germination, are, (as regards the non-nitrogenous constituents,) in direct proportion to the amount of starch in the seed." Further, "poor and sickly seeds will produce stunted plants, which will again yield seeds bearing in a great measure the same character." On the contrary, he states (on page 61 of the same book, foot note,) that "Boussingault has observed that even seeds weighing two or three milligrames, (l-30th or l-20th of a grain,) sown in an absolutely sterile soil, will produce plants in which all the organs are developed, but their weight, after months, does not amount to much more than that of the original seed. The plants are reduced in all dimensions; they may, however, grow, flower, and even bear seed, which only requires a fertile soil to produce again a plant of the natural size.'' These seeds must be diminutive, yet placed in a fertile soil they give a plant of normal dimensions. "We must thence conclude that the amount of starch, gluten, etc.—in other words the weight of a seed—is not altogether an index of the vigor of the plant that may spring from it.

Schubert, whose observations on the roots of agricultural plants are detailed in a former chapter (p. 242,) says, as the result of much investigation—"the vigorous development of plants depends far less upon the size and weight of the seed than upon the depth to which it is covered with earth, and upon the stores of nourishment which it finds in its first period of life."

Value of seed as related to its Density.—From a series of experiments made at the Royal Ag. College at Cirencester, in 1863-4, Prof. Church concludes that the value of seed-wheat stands in a certain connection with its specific gravity, (Practice with Science, p. 107, London, 1865.) He found:—

  1. That seed-wheat of the greatest density produces the densest seed.
  2. The seed-wheat of the greatest density yields the greatest amount of dressed corn.
  3. The seed-wheat of medium density generally gives the largest number of ears, but the ears are poorer than those of the densest seed.
  4. The seed-wheat of medium density generally produces the largest number of fruiting plants.
  5. The seed-wheats which sink in water but float in a liquid having the specific gravity 1.247, are of very low value, yielding, on an average, but 34.4 lbs. of dressed grain for every 100 yielded by the densest seed.

The densest grains are not, according to Church, always the largest. The seeds he experimented with ranged from sp. gr. 1.354 to 1.401.