This section is from the book "The Gardener V3", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
It has been recently asserted that the reason why old Melon seeds produce more fruitful plants than young seeds produce, is because the starch the old seeds contain is gradually converted into albumen, which is less readily soluble than starch, therefore the plants raised from old seeds do not grow so vigorously and are more fruitful than stronger-growing plants raised from young seeds. This is advanced on the authority of Loudon. In the first place, such a change is an utter impossibility; in the second, in Loudon's days chemists had not ascertained the composition of Melon seeds, and therefore Loudon's statement was only assertion - and loose assertion too - as he could not possibly have known the chemical formula of starch and albumen, or he would never for a moment have supposed the possibility of starch being converted into albumen. Loudon's mistake was excusable; but how are we to excuse those who go on repeating it so long after the idea which gave it birth has been exploded 1 The truth is - and, practically, it is of some value to know it - that after a year or two Melon seeds gradually lose their vitality, and as the vital power becomes less the plants produced are less robust,, and - that is all.
There is a very erroneous idea entertained and acted on, that Melon seeds two or three years' old produce earlier and more fruitful plants than one-year-old seeds. It is certainly quite true, and by careful comparison we have satisfied ourselves of its being so, that plants raised from seeds old enough to have an impaired vitality generally show fruit-blossom earlier and in even greater abundance than when the plants were raised from seeds whose vitality was unimpaired. But the conclusion which seems to have been universally arrived at is quite erroneous. We have on more than one occasion proved what we are now saying. It is not from any positive quality possessed by old seeds,, but rather in consequence of an impaired vitality, that the plants are earlier and more fruitful. Lessen the vigour of plants raised from new seeds by using poorer soil while the plants are being nursed in pots previous to final transplanting, or by the use of smaller pots or a lower temperature than is consistent with a vigorous development, or by any means whatever whereby the constitution of the plants is brought to the level of plants raised from seeds with an impaired vitality, and you will find the results quite the same.
This being the case, any difference between new Melon and Cucumber seeds can be regulated at will and according to the appliances of the cultivator, - for not only can new seeds be brought to produce plants similar every way to that produced by older seeds by the "levelling-down " system, but equality may be restored to a certain extent by the "levelling-up " process as-well, by using soil a little richer than usual: but perhaps this is only putting the same fact in a different form.
On the same subject, under a somewhat different title, a writer in a •contemporary tells us, among other tilings, Low to produce crops of Peas, by simply using seeds of unimpaired vitality. Quoting the same authority - Loudon - he tells us that if we wish Peas of an earlier type, all we have to do is to take Peas for seed which had not been quite matured. The observation which led to such advice was surely of the shallowest description. That immature Peas used for seed really do produce a somewhat earlier crop we know to be true, but to say that an earlier type can be thus produced is wholly incorrect. An early tendency thus produced is not permanent, but a merely accidental circumstance, and wholly on account of an impaired vitality. Impair the vitality of the plants to an equal extent in other ways by sowing in thin, hot, or poor soils, or by transplanting and so injuring the roots, and the result will be quite the same, - the enhanced earliness being produced wholly in consequence of the altered circumstances, and not because of an inherent quality in the seeds.
Another case which we have carefully proved, and which has more than once proved itself, much to our chagrin, has been in the case of Leeks sown in heat about the first of February, to be grown on for exhibition purposes in August and September. Whenever the seeds have been a little inferior, either from age or imperfect maturation, we have always found that the produce of such seeds was inferior to the produce of plump, well-ripened seeds; and not only so, but a large percentage of those produced from the inferior seeds ran to seed by August, while with first-rate seed we have found it quite safe to sow as early as the middle of January.
Numerous other instances might be cited to show that many failures arise from seeds with impaired vitality. Some years ago Mr Simpson raised the question, Why the earliest crops of Turnips sometimes ran straight to flower from the seed-leaf, when under what one would consider fair circumstances; and sometimes, under less favourable circumstances, a fair crop was secured before the spindling for seed commenced'? No one answered the question thus raised. Probably the experience of cultivators was identical to the querist's, and as little able to "tell the reason why" as he. Since that time we have never seen a sowing of these "bolt" prematurely without considering the circumstances under which they had been grown, with a view to discover the cause; and as showing the truth of what we have written above, we recall two different sets of circumstances under which part of the crop bolted and the other did not. The first happened some time ago. In digging over some ground which had been dug and half of it manured the previous autumn, we gave the whole a good dressing of well-decayed manure, not knowing that one-half had been dressed before. On this ground our earliest Turnips were sown.
Those on the twice-manured portion perfected a very fine crop: those on the once-manured nearly all ran to seed without bulbing at all. Since then we have taken care to have the ground intended for our earliest Turnips liberally manured, and have had good reason to be satisfied with the practice. The other occasion was only-last season, and it goes to prove that a vigorous growth, in the earlier stages especially, helps materially to prevent premature seeding. We had some seed left from the previous year, and we made an equal sowing of old seed and new. From the first a difference was discernible. The new seed came up first and strongest; the new seed gave us some find Turnips, with only a few "seeders:" the old seed gave us only a few bulbs, and a fine crop of plants which ran prematurely to seed. But we need not multiply examples. It is well enough known that Celery, Lettuce, etc, whenever they get a check, have their tendency to seeding increased, and when kept growing vigorously the tendency is in part overcome. Poverty, drought, crowdedness, and many other influences, hasten the flowering period; and, last but not least, although far too often overlooked, seed with a vitality not strong enough to give a vigorous growth from the very first.
We ought to aim at a vigorous growth from the very first, because weakly seedlings are only made vigorous plants with great difficulty, and often enough it proves to be an impossibility.
Now these are facts well worth knowing and acting upon. Low-priced seeds are often enough very dear seeds, although inexperienced persons sometimes think otherwise, until taught the truth through painful experience. Old seeds are often enough worse than useless because they lead to a cumbering of ground with weakly produce which might have carried a robust vegetation. With a proper method, and with a knowledge of what is wanted, together with the amount of seed required to crop a given space, there is no reason why any seeds should be left over from one year to another; and when there is, it is as often as not the falsest economy to use the old seed instead of buying new.