BLUE SPRINGS, Mo. – If you are planning a large vegetable garden this year, growing your own transplants offers advantages over direct seeding. Germinating seeds in a greenhouse, hotbed or your home can reduce transplant mortality and improve seedling vigor, said a University of Missouri Extension horticulture specialist.

“You can hand-select transplants to set out in the garden, which will lead to more uniform production,” said Marlin Bates. “You won’t have to hope your favorite varieties will be available at the garden center or worry about pest issues that can carry over from commercial production facilities.”

The ideal place to start seedlings is in a greenhouse, which offers space to work and buffers temperature swings. The next-best option is a hotbed. These boxes have clear covers, are set outdoors and should have a source of supplemental heat.

For indoor production, you can still take advantage of natural light. South-facing windows are best for transplants, although they will still need supplemental light, Bates said. Hang fluorescent lights designed for plant growth 4 to 6 inches directly above the plants. Suspend the lights in a way that lets you adjust their height to maintain the proper distance as the seedlings grow.

Before transplanting seedlings to the garden, harden the plants by lowering the indoor temperature by 10 degrees for about 10 days or by placing them outside in a protected area.

Planting seedlings in the late afternoon or on a cloudy day will help transplants recover more quickly, Bates said.

The MU Extension guide “Starting Plants from Seeds” (G6570) is available online at extension.missouri.edu/g6570.

"Building and Using Hotbeds and Cold Frames” (G6965) is available online at extension.missouri.edu/g6965.

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