Follow these guidelines when adding new plants to your garden, whether you transplant seedlings from 6-packs or more mature plants from 1-gallon containers. Begin by choosing healthy nursery stock. Select stocky, deep green plants with buds (shown). Spindly plants in full bloom make poor transplants. Avoid plants with discolored or wilted leaves.
Choose healthy bedding plants: Shorter plants, with lots of side branching and healthy stems, transplant and grow better than overgrown, gangly plants. If transplants have become root bound (roots are crowded and encircling each other), gently loosen the root ball at planting time.
Handling transplants: Transplant after the last frost date on a warm, cloudy day. Before you plant, prepare the soil by loosening it with a cultivator or hoe, leaving no bulky clods. Using a trowel, shape a planting hole large enough to accommodate the root ball of the transplant as well as its growth.
Easy transplanting: Set the root ball of the transplant into the hole, filling in around it with soil. Leave enough space between seedlings to allow each plant to reach its mature potential without crowding its neighbors.
Large transplants: Transplant larger nursery stock the same way you would seedlings. Control invasive plants, such as tansy, mint, or bamboo, by planting them in their pots -- cut the bottom out of the pot first -- to contain their runners. Do not fertilize transplants for several weeks, Instead, water thoroughly, using a splash of B vitamins to help overcome transplant shock. Water regularly until plants show new growth, indicating they're rooting and surviving well.