Asters, alyssum, balsams, candytuft, celosia, coleus, dianthus (pink), lobelia, mignonette, petunias, phlox, portulaca, ricinus, salvia, verbenas, vinca, roses, zinnias, may all be started from seed. The greatest secret of success is to keep the plants from crowding, and keep pinched back to make bushy plants. Salvias and coleus are the tenderest of these plants. The others can go out to the frames, if room is scarce, as soon as the weather becomes settled.
PLANTS FROM CUTTINGS
The method of choosing and rooting cuttings has been outlined in a previous chapter (see page 29). In greenhouse work the main difference is that they are taken in much larger quantities. For this reason it is usually convenient to have a cutting bench instead of the flats or saucers used in rooting house plants. The bench should be three or four inches deep, filled with medium coarse, gritty sand, or a substratum of drainage material. If possible, have it so arranged that bottom heat may be given—this being most conveniently furnished with pipes under the bench boxed in. (The temperature required for most cuttings will be fifty to fifty-five in the house with five to ten degrees more under the bench.) The cutting bench should also be so situated that it readily may be shaded, as one of the most important factors of success is to prevent the cuttings from wilting at any time—especially just after placing in the sand. After rooting, the cuttings are put into small pots or flats as already explained.
Spring stock of some plants, such as geraniums, are rooted in the fall—September to November. Others, which make a quick growth, such as petunias, not until early in the spring,—last of January to April, but for the most part in February. In the former case, cuttings are taken just before frost from outside plants, or later from stock plants lifted and taken indoors; in the latter case, stock plants are taken in and carried through the winter in a more or less dormant or resting condition; being kept rather dry and started into active growth in January. The new growth furnishes material for cuttings, which are grown on as rapidly as possible.
The following plants are treated in one of the above ways; further details in any case may be found in the first part of the book:
Alternantheres Heliotrope
Begonias, fibrous rooted Ice Plant
Coleus Paris Daisy
Cuphia Petunias
Geraniums Salvias
Ivy Geraniums Vincas
German Ivy
BULBOUS BEDDING PLANTS
The bulbous plants are started directly in pots, or in flats and transferred to pots, as described in individual cases in the preceding pages.
Cannas, tall
Cannas, dwarf flowering
Dahlias
Caladiums
Tuberous rooted Begonias
are the sorts for which there is most demand.