When cheapness of the seed is the main consideration such promiscuous harvesting may be permissible, but when only the best is desired careful selection and preparation becomes necessary. Even if the parent plants are of choice types, not all the seeds from them are equally good. The seed, for instance, which has been gathered from a stool which has flowered side by side with an inferior kind, and at the same time, may be worthless, because it has been fertilized badly. Then the last heads generally yield nothing but doubtful seed which seldom reproduces the proper type. The seeds which grow at the end of the shoots also, as well as those produced by the upper and lower extremities of the stem, have the same defect.
In order to insure the production of the very best asparagus seed a sufficient number of pistillate or seed-bearing plants, which produce the strongest and best spears, should be selected and marked so that they may be distinguished the following spring when the shoots appear. These clumps should be close together and near some staminate or male plants which have to be marked likewise, as without their presence fertile seed can not be produced. The number of the male to the female plants should be about one to four or five. The following spring all the sprouts of the selected male plants are allowed to grow without cutting any. On each hill of the female plants the two strongest and earliest stalks are allowed to grow, cutting the later appearing spears with the others for market or home use. Thus these early stalks of both male and female plants bloom together before any other stalks, and the blooms on the female plants will be fertilized with the pollen of the selected male plants. This last is of prime importance, for on proper fertilization depends the purity of the seed as well as the vigor of the resultant plant. Not all seed of even a good plant properly fertilized should be used for reproduction, as of the seeds gathered from any plant some will be better than others. Only the largest, plumpest, and best matured seeds should be used, for by saving these the most nearly typical plants of the sort will be most certainly produced. The selection of the best seed from typical plants is as essential to success as are good soil, thorough cultivation, and heavy manuring.