Chances are the plants you will buy for this summer's garden got their start right here in Howard County. Our area is home to many seasonal wholesalers who raise bedding and container plants for garden centers and roadside stands.
From January through June, Poplar Springsresident Deborah Hall manages a small greenhouse operation owned by her friends Tom and Sherri Smith at their Spring Mill Farm in West Friendship.
She says the informal partnership evolved naturally from their high school friendship and shared love of plants. Her earlier work at another Howard County greenhouse didn't hurt.
The three greenhousesat Spring Mill Farm are in use for just six months. Maintaining plants through the summer, and the cooling involved, is too expensive forsuch a small business, she says.
The bedding plants, vegetable seedlings and hanging baskets that result from the season's activitiesare sold wholesale primarily to local schools for spring fund-raisers. Some are sold at the farm's roadside stand on Route 29. Hall says the school business has become so regular that some now order specific plants, like yellow marigolds, that they know will be popular at their sales.
Almost all the plants started at the farm are hand sown. Those kinds of flowers that need to be started before January, or those that are difficult to handle as small seedlings, are ordered as "plugs." These are small fingered-sized plants that Hall sets into market packs, where they will grow into salable size. The geraniums andbegonias are usually done this way.
Seed starting for the greenhouse and seed starting for the home gardener have much in common. The first step is selecting the plants to be grown.
"Since we are so small," she says, "we pretty much pick out just what we like from the catalogs."
The plants meet several qualifications: they must be known to do well in Howard County, they must thrive in a greenhouse andthey must appeal to the public. Experience has taught Hall that somekinds of plants just don't thrive in a greenhouse.
Besides flowers, the trio starts a variety of vegetables -- such as eggplants, peppers and melons. They have learned that the tomato of choice in HowardCounty is Better Boy. Hall's own preference is the traditional Marglobe variety.
Seeds are planted in large flats. The first "must" that Hall advocates is using a sterile planting medium. Sowing in a commercial seed starting formula prevents a fungal disease called "damp off" that often overcomes small seedlings before they get the chance to develop.
Home gardeners can purchase seed-starting mixes at garden centers or hardware stores.
A technique that professional plant growers use that home gardeners usually don't is the application of"bottom heat."
By keeping the area under the flats warm -- between 65 and 75 degrees -- throughout the germination process, sprouting can be sped up by as much as four or five days, Hall said.
The greenhouse uses a 4-foot by 8-foot table that holds 20 or so flats. The area under the top of the table is filled with a layer of sand. Heating cables are placed at regular intervals in the sand layer, providing uniform warmth to the flats above. A plastic covering tops the flats to retain moisture.
Similar cables, with or without thermostats,are sold in garden supply catalogs, but Hall confides that at home, placing newly sown pots on top of the hot water heater works just fine.
Many plants -- tomatoes, for example -- take just one day to germinate with bottom heat. And the problem of rotting seeds is avoided.
Once sprouting starts, the trays move into the full, cool light of the greenhouse. Here is where a commercial grower has a distinct advantage over the home gardener without a greenhouse.
Bright lightkeeps the plants growing at a steady pace without becoming emaciatedlooking. "Leggy" is the term Hall uses, and it describes plants withelongated stems and few leaves, the result of the plant's effort to reach for more light. Even a sunny window sill will often produce leggy seedlings.
An inexpensive way for the home seed starter to compensate for lack of light is by using readily available fluorescent lighting -- shop lights --suspended about 5 inches from the tops of theplants. Keep raising the lights, or lowering the plants, as the seedlings grow. Most seedlings do fine with the lights left on for 15 or16 hours a day.
At the Spring Mill greenhouses, the seedlings aretransplanted to those familiar market packs when they are one-half to three-quarters of an inch tall.
Some varieties, like impatiens and begonias, are delicate and best handled by the leaves and not the stems. New leaves will grow to replace broken ones, but a damaged stem dooms the whole plant. All the plants are fertilized approximately every 10 days with a formula mixed with water.