Here are some great plants you can grow in your greenhouse for all year round profits
Annual Phlox
The lovely little annual phlox in a vast selection of colors will almost always be among your best sellers. They are useful anywhere. Suggest to your customers that these plants are most effective in the garden when planted in groups of half dozen or more.
Sow the seed in early March in light soil. Grow in the cool greenhouse and pot up in 2 or 3-inch pots in mid-April.
Bachelor Button (Centaurea)
This plant with its silvery-gray foliage, bright blue, pink, or pink and white flowers is a great garden favorite. Recommend it for beds, borders, cutting rows, or accent plants.
Sow the seeds in February, planting them inch deep in ordinary greenhouse soil or any seed-starter medium and grow them in the cool greenhouse. These seedlings will be large enough to be sold from 3- or 4-inch pots in May.
Balsam (Impatiens balsamina)
Balsams are old favoritesand they are constantly being improved as in the new rose-, camellia- or double-flowered types.
Sow balsam seed in March in pans or flats of sandy soil. The seed germinates rapidly when grown in 65 degree temperatures. Pot into 3-inch pots when the first true leaf shows, usually about 3 weeks after germination. They need lots of light, so grow them close to the glass. To obtain shapely plants remove the first buds from the main stem and side shoots.
Calendula
Calendulas, or pot marigolds, with their bright golden heads, are fine for garden color or for the cutting garden. They thrive in most any soil, and seeds sown in early April will produce large budded plants for late May or early June sales. Grow the seedlings in night temperature of 50 degrees.
Calendulas come in shades of cream, apricot, yellow, and orange. Grown under good conditions, modern calendulas are mostly doublesregular pompoms. If many single or deformed blooms show up on supposedly doubled varieties, they probably have been grown under too high a temperature.
Castor Bean (Ricinus communis)
Owners of new homesespecially in housing developments usually have common garden problems. Foremost among these is lack of shade and the immediate need for impressive-looking shrubbery or plants. The castor bean will fill both of these bills. These plants in one season will grow 8 feet tall and 5 feet wide, with very broad leaves. Suggest using castor bean plants also as patio plantings, boundary line markers, or to add a touch of interest to the new garden.
The beans are large. Plant each one in a separate 2-inch pot in March and grow in the cool greenhouse. In mid-May pot up in 4- or 5-inch pots.
Coreopsis
Coreopsis thrive in a sunny location. With their yellow, orange, red, and near-brown flowers, they add splashy color to the garden and are long-lasting cut flowers.
Start seed in the cool greenhouse in mid-April and you'll have salable plants from 3-inch pots in late May.
Cosmos
With lacy foliage and richly colored flowers cosmos make popular additions to most gardens. Most of them are about 3 feet high at maturity but some of the "Mammoth" hybrids grow to 5 feet. They thrive under the same conditions as coreopsis. Cosmos come in deep rose, rich crimson, white, pink, and orange, with single and double flowers.
Dahlia
Planted early in February, most dahlias will produce flowers from seed the first season. Certain varieties such as Unwins have become favorites for pot growing. You can purchase these in mixture and plant them in early February in the cool house for salable potted plants in May.
Gilia
The gilia genus offers several good garden species. I like Gilia rubra (sometimes sold as Ipomopsis); it features rapid growth and tall (3-5 feet) spires of bright red flowers. These make wonderful accent plants to place among low-growing perennials, as iris or hemerocallis, and they are among the most handsome of background plants. Although easily grown, this gilia is not too often seen. Its common names include standing cypress and Texas plume. There are also varieties with blue, pincushion-like flowers.
To have flowering plants in May, sow the seed in December in a cool greenhouse. As soon as the little plants are large enough to handle, usually in about a month, transplant directly into 2-inch pots of average greenhouse loam. Plants will flower right in these 2-inch pots, but you'll have larger plants and more flowers if you give one more transplantingto a 3- or 4-inch pot.