Bedding plants for flowers and vegetables are available as seedlings, known as transplants. They’re sold by Garden centers, nurseries and through the mail, or they can be grown in a bright window or under fluorescent gro-lights.
When buying transplants, the condition of the plant is often more important than its variety. A good transplant would be at least as wide as it is tall. It should have a stocky stem with dark green, thick leaves and, if possible, it should not be flowering. Choose the best, healthiest plants that are free of disease and insects. Avoid any neglected plants. Use caution when buying transplants after a cold, wet spring because they may not have been sold quickly enough. Avoid tall, thin and pale plants that have not received enough light or water.
The outdoor environment can be very harsh for a transplant. So, harden the transplants before planting to increase their chance of survival. Place them outdoors where they will receive direct sunlight and some wind for a few hours each day for a week. Gradually lengthen the amount of time outside each day. Move the plants inside at night if temperatures drop to near freezing. Keep them watered and plant them as soon after hardening as possible.
For more information, see the following ColoradoState Extension fact sheet(s).