Planting seeds produces plenty of annuals for the garden

It's time to start annuals that get off to a slow start, such as pansies, violas and snapdragons.

You should plan to replant the snapdragons a couple weeks or so later than the pansies and violas, which are more cold tolerant. While garden centers offer many favorites, the choices are seemingly endless when your grow your own, and the quantity will be, too, if you save all the little seedlings.

Use grow lights to ensure success. A fluorescent-type hung on a chain works best, as you can adjust the level to keep the light at an optimum 8 to 12 inches above the seedlings.

Providing bottom heat for the seedlings will also improve results. Heat mats or cables can be purchased at your local garden center.

Thin the seedlings as needed, especially after the first set of leaves form, to prevent overcrowding and keep the best plants. Just remember when sowing, include a few extras, but not too many.

• If cut roses you have put in a vase suddenly develop drooping heads, it may be because air bubbles are trapped in their stems. Float the entire stem in a sink full of warm water. Trim another inch from the stem, cutting on an angle below the water level.

Try to gently straighten the drooping flower head as the flower and stem continue to float and the cut end of the stem remains under water for at least half an hour. When the flower head hardens to a straightened position, the roses may be placed back in the vase.

• Consider using a free-standing plastic composter to compost in your garden. You can continue to put organic material from the kitchen in the composter during the winter because it keeps the material secure, so dogs and other animals cannot get into it.

Compost is the end product of composting — a process where organic matter is collected, mixed and allowed to decompose. Compost can be used to amend soil or as a mulch layer on garden beds and around trees.

In nature, deciduous leaves create a mulch layer that eventually decomposes. Like human-made compost, this natural recycling process returns nutrients to the soil and improves soil structure, and it is one reason why native plants growing in natural ecosystems usually do not need more fertilizer than nature provides.

Composting reduces the amount of garden debris that ends up in landfills and improves your garden's soil when it is amended with the compost.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.