Choosing Nursery Plants
Many annuals are easy to grow from seed, and some can even be started outdoors right in the garden. But if you plan to buy plants from a nursery, choose them carefully. Look for deep green, healthy plants that are neither too compact nor too spindly. They will do better if they are not yet in bloom when planted. If you can't plant them right away, keep them in a lightly shaded spot and water carefully.
Annuals need about an inch of water a week. If Mother Nature doesn't provide enough, you will have to help. Water deeply to encourage deep root growth, and try to keep the foliage dry during watering. If you must use an overhead sprinkler, use it early in the day so the foliage will be dry by nightfall, lessening the chance of disease.
The best time to plant is late in the afternoon. Before planting, water your plants well and also the soil in the bed. Remove the plants from their pots gently so you disturb the roots as little as possible. If they are in peat pots, tear the pots slightly to make it easy for the roots to grow through. If the roots are compacted, loosen them gently before planting.
The addition of a 2- to 3-inch layer of mulch will make the bed more attractive, reduce weeds, and conserve soil moisture. Organic mulches are best. Try bark chips, pine needles, shredded leaves, or peat moss. The following year the mulch can be incorporated into the soil and new mulch added on top, resulting in an improved soil.
Controlling Seedling Height
Seedlings can become tall and leggy if kept indoors too long. If your seedlings are ready to plant out before the weather is right, there are a few things you can do to slow them down. Reduce watering and don't fertilize them again until you are ready to transplant. Place them in a cool, bright location, and repot if their height is more than three times the diameter of the pot.