In the middle states the best growers make a practice of sowing the seeds in boxes about the last of April or first of May. Some make a couple of later sowings between that date and the first of June, sowing these in carefully prepared seed-beds in the open ground. This is to keep up a succession of flowers. So many sowings are scarcely necessary now that there are both early and late varieties to be chosen in the first place. The period of first sowing will allow for all, if kinds that flower at various times are chosen. In the Southern states a June sowing is recommended. A lath frame will keep the plants from parching.
Late Asters may be lifted for the house. It is a good plan if one wishes several of them for pot plants to sow seed of them in July, under a lath frame where they will be shaded somewhat and protected from drying winds until up and of some little size. These will come into bloom before the first Holland bulbs are ready for the window, and will remain in full beauty for several weeks. An August sowing will give late winter and early spring flowers.
Asters are easily transplanted and should never be allowed to become cramped for room, or to be grown in the shade of other plants. If carefully done, an Aster in almost full bloom can be taken up and replanted without injuring it in the least. So there is no excuse for letting them be crowded in either seed-box or seed-bed.
Preparing an Aster Bed
There is no use trying to get good Asters from plants in poor ground. They are gross feeders. They dislike sandy soil the most of all. Clay ground is better for them than sand, and loamy soil the best of all. If the soil is sandy, plant Asters so as to leave a little depression around each plant. The water will thus sink about them and more moisture be retained. Sour, undrained soils where the water stands should be raised a little above the level of the lawn, if for Asters, so that excess of water may drain off. They like moisture but not stagnant water. Whatever the character of the ground, spade it deep so that it may be mellow, and make it very rich. If the ground is to be spaded a foot deep, a 3-inch layer of rotted manure is about right to dig in. Rotted manure does not mean fresh or lumpy manure. It means that the fertilizing element shall have been rotted until ready to drop to pieces. Stable manure is too fiery. Cow manure over a year old is best. Many expert Aster growers scatter an inch of unleached hardwood ashes over the bed before it is broken up and spade it in with the manure. They claim it both suits the Aster and helps to keep off root-lice.
It is usual to plant tall or half dwarf varieties in the center of the beds, and use some of the dwarf Asters for an outside row or border. The tall kinds should stand 10 to 12 inches apart in the row. The dwarf ones about 8 inches apart. Asters make a sightly bed because of the uniform height of each class and because of their blooming at the same time.
Hot dry soil quickly spoils Asters. About July mulch them well.
Mulching and Watering
Two inches of coarse manure spread out well over their roots is the best mulch of all, as every rain washes nutrition from it down to the roots below. Chip dirt, pine needles, or grass clippings will do, or anything else that is light, yet will let the rains or waterings leach through. No one who has not actually tried it can know of the help a mulch really is to Asters. I doubt whether first-class flowers can be obtained in dry, windy countries, or in hot, sun-scorched valleys without its aid. Asters love the sun, nevertheless unless their feet are kept cool and moist they inevitably burn and wilt. A mulch keeps the ground cool, and it keeps it moist also.
I know of Asters that gained the prizes at county fairs that were regularly soaked once a week with the suds from the weekly washing. In most climates a thorough drenching of the ground once a week will promote a luxuriant growth of the plants. There is nothing gained by watering in dry weather unless the ground is mulched. Without this protection the ground will bake as hard as a brick and the plants suffer more than if no water had been given. In some sections hot dry winds prevail through August and September. This is most trying to Asters. If there is a tank, or system of water works, a good sprinkling, not only to the roots but of the foliage as well, will revive them wonderfully. Use the hose about sunset. By morning the plants will be entirely revived.