Here is a nice selection of plants that are popular with the public and can make you good profits:
Monkey Flower (Mimulus)
This is indeed a versatile plant. A semi-trailer in shade, it is good for window boxes, outdoor planters, and hanging baskets. With full sun it grows upright and is excellent for use in the border. The brilliantly colored flowers are light yellow splotched red, or red with yellow markings. Here are flowers to liven a garden throughout the summer.
Sow mimulus seed in January in the warm house. Transplant in late February to 2- or 3-inch pots of porous growing mixture. These will be well established for the spring and summer business.
Morning Glory (Ipomoea)
Propagate strobilanthes through cuttings. The purchase of one plant in a 4-inch pot in the fall will give you fifty or more plants in 3-inch pots for spring and summer sales. Grow it in a warm house and keep it nipped out for bushy growth. Stick the nipped out pieces in a propagating case and you'll have still more plants for sale.
Sow the seeds in April. They are best planted directly into 2-inch pots of ordinary greenhouse soil. If you have a heating cable in your greenhouse, give some bottom heat as a starter. Lacking a heating cable, start them in a warm greenhouse. As the vines grow, the potted plants can be moved to the cold frame or placed in a cooler part (50 degrees) of the greenhouse.
Although there are many new varieties, Heavenly Blue remains high on the list of favorites.
Nasturtium (Tropaeolum)
Nasturtiums, with their blaze of yellow, orange, and red flowers, are versatile. Plant seeds in early March directly into 2-inch pots of soil. Grow them in the cool greenhouse. The tall vining types are generally listed as "old fashioned fragrant," or "fragrant giants."
Scabiosa
This sturdy and popular annual has fragrant, pincushion-like heads of white, pale yellow, salmon, pink, scarlet, or blue flowers; in fact, pincushion flower is one of its common names. Start the seed early in March in the warm house in average greenhouse soil. Pot singly into 3- or 4-inch pots in April and plants will be well established for May sales.
Schizanthus
Often listed as butterfly flower, fringe flower, and, perhaps most commonly, as poor man's orchid, schizanthus is lovely enough to use in situations calling for a specimen planting. The flowers of this annual, looking like tiny orchids in purple marked with white, red, or deep yellow, are borne in clusters.
Sow seeds in October for blooming or budded May sellers. Keep well moistened and grow in 60-degree temperature. In March, pot up two plants to a 3- or 4-inch pot, pinch out tips to make good branching, stake, and grow in good light.
Summer Cypress (Kochia)
The summer cypress can become a garden nuisance, but if restrained, it is a handsome shrubby annual, wonderful to use in the newly established garden or for special landscaping purposes. This plant with its neat conical growth resembles the small expensive pyramidal evergreens so popular in foundation plantings. Suggest summer cypress for use in temporary foundation planting, for fast growing hedges, or specimen plants for the garden.
The foliage, green throughout the summer, turns red in fall. I like its other common name, Mexican burning bush.
Sow the seed in March and grow in a warm house. Pot up in 3- or 4-inch pots in late April. The variety most commonly grown is Kochia scoparia.
Stocks (Matthiola)
Stocks are both annual and biennial plants. They are good for the sunny garden and the flowers are marvelous in arrangements. Some of the annual types flower 10 to 12 weeks after seed planting. Flowers are white, pink, red, and navy blue.
Sow the seed in March in a porous mixture. Grow in a warm house. As soon as the seedlings can be handled wellperhaps 2 weekspot up in 3-inch pots.
Any of the giant mixed strains produce handsome plants. There is also a dwarf 10-week stock on the market. This one, growing to 12 inches, has fragrant, large, double flowers. Mixtures listed as "column type" bear both single and double flowers on exceptionally long stems.
Strobilanthes
Suggest the use of a few strobilanthes (sometimes called conehead) plants to the gardener who has a yen for beautifully colored foliage. Although there are several species available, none is quite so handsome and easily grown as S. dyer-anus. New growth is deep red-purple, older leaves are silvery orchid. Strobilanthes makes a pretty border plant and it adds much to terrace, patio, outdoor planters, or window boxes.
The morning glory vines provide a wealth of exciting garden materialto help out in so many different gardening situations. New gardeners need fast-growing material for trellises and fences, as a screening for service areas, or accent plants grown on or near a wall. Morning glories provide all thisand, in addition, produce an abundance of blue, rose, or white flowers.