When the grandiflora or old type of Sweet Pea was the only one in existence, seed growing presented few difficulties. It was a common sight then to see acres of plants unstaked, from which quite good crops of seed were obtained; now-a-days. if the same method was tried with the waved varieties, the result would be a complete failure.
The reason is that the waved forms with a very few exceptions are not free seeders. The reproductive organs are more delicate; they are not so well situated to assure pollination being accomplished, and adverse weather conditions at once tell on them.
Sweet Pea growing for seed has therefore "changed hands" in England, and what is done now is done by growers who are more or less experts. It has been found that spring-sown plants are much less reliable than autumn-sown ones for seed, and therefore the practice of autumn-sowing is generally followed by the best firms. The seed may be sown in the open where the plants are to remain and flower if the land is well drained and the exposure good, and where such sowings are successful and come through the winter untarnished, the yield is always good, provided a decent summer follows. In England it is always necessary to stake Sweet Peas in some way; they cannot be left to support themselves as in California, and therefore it is necessary to sow in rows at least five feet apart. Staking of course in the field does not require to be done so carefully as in a garden, and such stakes have to be used as can conveniently be obtained by cutting down hedges or brushwood, or by using wide meshed wire netting.
It will be readily understood that sowing seeds in the open field of very choice varieties is at all times rather a risky business, and besides valuable stock seed can be made to go a very much longer way by being sown in pots or boxes under glass and planted out in spring. This is the method followed by my firm, Messrs. Dobbie & Co., at their farm in Essex, and the results obtained by them are admitted to be the best in Europe. It means more work, more expense, and a large extent of glass, but success is much more certain, and, as I have already said, the utmost possible can be made out of scarce things, yet, in addition to the method just described, it has been found necessary by Messrs. Dobbie & Co. to adopt a still more reliable system, i.e. the growing of some sorts under glass for seed. Several of the most charming varieties are so uncertain in the open air that large glass houses have been specially built to grow them in, and the success which has been obtained by this method has been great. I do not say it would pay in a wholesale way, but when a firm like Dobbies is growing almost solely for their own retail trade, it works out all right.
The harvesting in England is done by hand picking. The pods begin to get ripe by the end of July and they require to be gathered once or twice a week according to the weather conditions which prevail. In some seasons this work may go on until the end of September, but such prolonged seasons are not liked as they mean the process of ripening is slow and unsatisfactory.
In England where the crops are grown on stakes, the process of rogueing is easily done and growers have no excuse for not purifying their stocks, if they possess the knowledge and skill necessary to do the work. People who do not possess such, should certainly not call themselves experts. A great work has been done in the way of renewing stocks in recent years. Varieties are raised by cross-fertilization, identical with the older named varieties, and many of the stocks on the market now are not the original ones, but new re-created ones.
The care of stock seed is an expression which may not convey much to the ordinary reader, but it is the crux of all successful seed growing, whether it be Sweet Peas or anything else. Just as the rearer of pedigree cattle looks ever and always to the parents of his stock, so does the raiser of good strains of seeds. In two generations a stock, however good, could be ruined, and in two generations a stock, however good, can be improved; but to accomplish the latter oftentimes requires a life's knowledge and experience, and further, it always means living in closest touch with the plants or animals to observe their points - to detect weaknesses and to be ready to take advantage of the slightest improvements. In conclusion, permit me to say, never grudge a fair price for pure seeds. Life is too short to run the risk of disappointment, and the loss of a year, by risking cheap products in one's garden.