Starting Bedding Plants Indoors Can Be Tricky

By Dennis Hinkamp

Avid gardeners going through withdrawal this time of year can often be found engrossed in seed catalogs and mumbling about starting flower gardens indoors.

Starting gardens indoors requires a great deal of work and time, which is why most people leave growing bedding plants to greenhouses and nurseries, says Jerry Goodspeed, Utah State University Extension horticulturist. Still, there are many reasons one might decide to start growing bedding plants indoors. By growing bedding plants its possible to grow varieties that may not be grown by local growers.

He says most seeds can be started (germinated) in a warm, dark location. They need a very light potting soil. Starter soil mixes can be purchased from the local nurseries. Some people put their seed flats on top of a furnace or freezer. This helps warm the soil to promote good germination. Be sure to read the seed package label in order to provide optimal germination requirements, and never over-water the seeds. Once the seeds germinate and the plants start to appear, they will need as much light as possible.

"Starting bedding plants indoors requires either a solarium, small greenhouse, or a room equipped with growing lights," Goodspeed says. "Lighting is the major obstacle for most people who are growing bedding plants because windows usually don't provide enough light to allow for proper growth and development of bedding plants."

If a greenhouse or atrium is unavailable, he says grow lights or good flourescent lights can be used. Keep the lights about 4 to 6 inches above the plants. They will need 16 to 18 hours of exposure a day.

Small plants also need to be fertilized, Goodspeed says. Apply a water-soluble fertilizer during each watering. It should be diluted to prevent excess salt build up and wasted fertilizer. Watch the plants as they grow. Their appearance can be a signal when they are lacking fertilizer.

"Let the plants grow until their second set of true leaves begin to emerge," he explains. "If they are getting enough light, this will occur before they are a couple of inches tall. Once the plants have reached this size, they can be transplanted. If only a few seeds were germinated in a larger container, they may remain in the same container and not be transplanted."

If the plants are crowded, Goodspeed suggests transplanting them into a larger container with good drainage and enough room for the roots to grow. They can stay in this container until they are ready to be placed outdoors. Keep supplying fertilizer and adequate water to keep the plants healthy. The light should still be within 4 inches of the plants if it is artificial.

"These are simplified directions for growing your own bedding plants," Goodspeed says. "There are diseases and insects to also worry about and unforeseen mistakes. Anyone interested in raising their own bedding plants should allow at least a year to gain a little experience. Start small and acquire the necessary skills on a few plants."

Read the seed labels and know how many weeks are required before they can be planted outdoors in the spring. Do not start plants too early or they might take over the house, he warns. Bedding plants grown too large in the house will not necessarily mean larger plants in the yard. Some do not transplant well if they get too big.


For more information, contact your local USU County Extension office.
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