The principal objection which has been made against this system of not transplanting is that it does not admit of a careful choice of plants, as the plants must be kept in the places where sown, while in the transplanting method we need use only the choicest plants; then, if two or three seeds come up close together, it is very difficult to thin them out, and if left they will produce an inferior growth.
In the tests made at the Missouri Experiment Station, Prof. J. C. Whitten found that it is much better to plant the seeds in six inches of rich, sandy soil in the greenhouse or hotbed, in February or early March, than to wait two or three months for outdoor planting. Professor Whitten advises to "sow liberally, for seven-eighths of the seedlings should be discarded. When the seedlings are three inches high, select those which have the thickest, fleshiest, and most numerous stems, and pot them. They vary more than almost any other vegetable. Many that appear large and vigorous will have broad, flat, twisted, or corrugated stems. Discard them. Beware, also, of those that put out leaves close to the soil. These will all make tough, stringy, undesirable plants. The best plants are those which are cylindrical, smooth, and free from ridges. They shoot up rapidly, and attain a hight of two inches before leaves are put out. They look much like smooth needles. This matter of selecting the best plants for potting, and subsequent planting out, is of the greatest importance in asparagus culture.
"These young plants should first be put in small pots and moved into larger ones as soon as they are well rooted. They may need to be shifted twice before they are planted out-of-doors, which should be done when danger of frost is over. Started in this way they continue to grow from the time they are planted out and reach very large size the first season. In the case of nursery-grown plants, where seeds are sown directly out-of-doors, the young seedlings start very slowly, are very tender during their early growth, and if the weather is unfavorable they hardly become well established before autumn."
[Illustration: FIG. 13--ONE-YEAR-OLD POT-GROWN ASPARAGUS PLANT]
Fig. 13 shows a one-year-old plant started in February in the greenhouse and transplanted to the field the first of May. Plants grown in this way reach as good size in one year as the nursery-grown plants usually do in three years.