This section is from the book "The Florists' Manual", by William Scott. Also available from Amazon: The Florist's Manual.
A large genus, mostly hardy perennials, widely spread throughout the world. Many of them belong to North America and are the flowers of our fields, and of these many are worthy a place in the hardy garden. It is in the annual, the Chinensis, section that we are interested.
Of all our so-called hardy annuals the aster takes the leading place. Most all of our customers want a few. They are planted in the mixed border, or occupy whole beds, and with the commercial florist who grows for cut flowers they are a leading article. To obtain a good strain and cultivate them well is a matter of great importance to many of us. From the middle of July till frost cuts them off they are a prominent feature in all our flower stores.
Twenty years ago the raising of aster seed was left largely to the continental Europeans, but nowadays as good a strain as exists can be obtained here, and any of us who has the time and industry can save his own aster seed. The finest flowers of the purest colors should be marked and tied and allowed to get thoroughly ripe, when the stalks can be cut and put away in a cool, dry place and the seeds separated at your leisure.
In the following directions for the raising of the young plants from the seed to planting time I have endeavored to be explicit, as the same rules will apply to the raising of other annuals, such as stocks, zinnias, phlox, etc., and to which in their order I shall refer the reader to asters for directions for raising the young plants.
The seed should bo last year's crop; older seed may grow but it is not to be depended upon. Successive crops may be wanted, or some early flowers grown under glass, so sowing can be done from middle of February till middle of April and even later. Sow in pans, or, if large quantities are wanted, in flats two inches deep. Always sow in colors. Fill the flats about even full with a light soil to which has been added a fourth of very rotten stable manure or thorouhly rotted leaf-mold, then press down with a piece of board or a block, which will carry the soil down half an inch below top of flat. Then with a fine rose or sprinkler on the watering pot (or, to save labor we have the sprinkler screwed on the end of a 3/4-inch hose), give the soil in the flats a good watering, sufficient to wet the soil through to the bottom. In half an hour sow the seed. Why we wait is to give the soil time to dry on the surface so that the seed can be lightly pressed into the soil with the board without the soil sticking to it. After we press the seed down we sift over the covering of soil. Whatever soil you use for covering it should not be of a texture that will bake and form a crust. Loam and leaf-mold, half and half, will do for the majority of seeds.
Field of Asters Growing for Cut Flowers for the Chicago Market.
The question is often discussed as to how deep seeds should be covered. As a rule the covering may be about the thickness of the seed, but we are sure that many seeds sown outside are covered six times their depth. With the aster and similar seeds we sift the compost on till all the seeds are out of sight, and that is sufficient. Another pressing down of the covering and the least amount of watering will do, as you now have only that thin surface covering to wet. The thickness of the seed in the flat or pan must be entirely a matter of judgment, since it is poor economy to sow very thickly to save space, as the seeds occupy a comparatively small space. I would say that if with asters every seed had a little square of one-eighth of an inch to itself it would be about the ideal way of sowing it, but spacing that or any of our seeds is out of the question. You had better err, however, on the safe side and sow thinly, for if crowded at the start it is a poor beginning for the little plant.
Seed when first sown (contrary to plants, which it does not hurt to let get on the dry side and then copiously water) should be kept at an even degree of moisture with no extremes. The flats should be kept in a shady place till the seedlings are above ground, when they should get the full light and not be allowed to draw up for want of light and ventilation. When well up less watchfulness is necessary. A temperature of 55 degrees at night brings up the seed nicely and keeps the young plants growing till time to transplant into flats or into the hotbed or bench.
As soon as they have made the first character leaf they should be transplanted. This is an operation that should be done very quickly but should be well done, which is more essential. While the little plant is held by the tips of the leaves by one hand, a rather blunt stick, held in the other, makes a hole in the soil into which let the roots of the plant hang down straight, and then with the stick press the soil around the roots. The plant should be so far in the ground that its seed leaves are only just above the surface. In pressing the soil around the plant don't make a point of squeezing the soil around the neck of the plant near the surface; that is not the particular place. Put the stick away down by the side so that soil is firmly pressed around the roots; that is the most important operation. If watered at once, thoroughly watered, and shaded for a day or two from the brightest sun, the seedlings scarcely feel the transplanting.
In the flats for plants we intend to sell to our customers in May and June we put the plants about one inch apart. If sown middle of March it is near the middle of April before they are established in the flats after being transplanted, and they then go into a cold-frame, where in May the glass can be removed. If very large quantities are handled they can be transplanted at once into a coldframe if the soil is dry and warm. If you have no greenhouse the whole operation can be done by the help of a hotbed.
When extra early asters are wanted they can be taken from the flats in which they were transplanted and put into 2 1/2-inch pots. In this way they will transplant with safety to the open ground. A great many asters are now grown on greenhouse benches. For this purpose sow middle of February. For our general crop we sow middle of March. Some of the varieties grow very tall when flowered under glass and need staking and lots of head room. They pay for the labor because you get fine, long-stemmed, clean flowers. Under glass they must be given plenty of water and frequently syringed - well syringed, for red spider and thrips are ever ready to attack them in the hot weather.
For cutting we plant our asters in the best and deepest soil we have, and if it is inclined to keep moist, so much the better. Plant eighteen inches between rows and twelve to eighteen inches apart in the rows, according to variety. When first planted out the small black jumping fly, often called the turnip fly or flea, is very troublesome, eating holes in the leaves. A syringing with a solution of Paris green and extract of tobacco will kill the fly.
Violet growers who do not lift their plants till September can make good use of their benches by devoting them to asters during the summer. If planted end of May they are out of the way during August. We have also thrown out a bed of worn out carnations and filled it up with asters. No fresh soil is needed; in fact the asters grow so rampant under glass when well supplied with water that too rich a soil is detrimental. But out of doors they want a deep, rich soil, and in prolonged dry spells must be copiously watered. Asters should be always within reach of the hose or some means of irrigation.
Of late years a small beetle has given us much trouble. It is very like the squash beetle if not identical. It punctures the leaves but is little noticed till the buds begin to show color, when it finds its way into the bud and chews the tips of the petals, destroying many flowers. As soon as the plants are established in the open ground spray with Paris green, a teaspoonful to a pail of water; you may have to do this two or three times before the buds appear.
There are many strains and varieties of asters. The large, strong growing, branching variety raised by Mr. Sem-ple, of Pittsburg, is excellent for cutting. Vick's Branching is of about the same character. Then there is the Truffaut's Peony-Flowered, very fine if true, and grand colors; Victoria, finely formed; Comet, finely curled petals; Jewel, very compact, incurved petals; Betteridge 's Quilled, a dense mass of short petals with a fringe of larger ones; and many other strains, all good if well grown, but Semple's though a few weeks later than some others, will be found to be grand.
Under this heading I have dwelt at some length on the operation of sowing seed, for I consider raising many of our plants from seed the most important part of the grower's occupation. It is the most delicate, and if not requiring the most skill it certainly taxes your patience and demands closer attention than any other method of propagation. Asters are by no means difficult to handle (quite the contrary) but all seeds need care. You can put cuttings into the sand very clumsily and if shaded you can trust most anyone to water the bed and count on success, but there are many things to watch in raising seedlings.
They are often unevenly sown, or careless watering will wash most of the seed to one corner of the box. When just germinating, if allowed to get very dry all your work may be in vain, or if not shaded when just peeping through the surface they may be burnt up. Skillful and proper management in sowing is one great part of it and constant watchfulness the other.
I think the plan of roasting or baking the material with which you cover the seed is most excellent, especially for those seeds that take considerable time to germinate, for it kills the seeds and spores of weeds and mosses and other low organisms that so soon take possession of an unoccupied surface. A piece of sheet iron over a brisk fire will enable you to quickly roast sufficient soil to cover a great many flats of seed. And if the whole mass of soil in which you sow as well as cover has been baked, so much the better.