March is prime seed-starting time. So if you have a yearning to dig in the dirt, give it a try. Starting plants from seed allows you to choose from an almost limitless range of flowers and vegetables - from the latest hybrids to heirloom varieties. And it can save you money because buying seeds costs a lot less than buying plants.

Here are a few things to do and to avoid when you're starting from seed:

DO

Use new seeds. Older seeds may not germinate well or at all. Onion seeds keep for a year or two. Other vegetable seeds, including tomato, cabbage, cucumber, lettuce and radish, can stay viable for four to five years.

Start with clean containers. To help prevent diseases, use new containers to start seeds or thoroughly scrub used containers, soak them for 20 minutes in a mix of nine parts water to one part bleach, then rinse thoroughly.

Provide some heat. Start seeds on top of a radiator or refrigerator or use a heating mat. Warm soils helps seeds germinate more quickly and more uniformly.

Keep potting mix moist. Water with lukewarm water and keep mix moist but not soggy.

Provide plenty of light. Use fluorescent lights and keep them 4 to 6 inches above the plants. Lights should be on for about 14 hours per day.

Feed seedlings. Once the seedlings have a few sets of leaves, feed with a water-soluble general fertilizer mixed at quarter strength once a week. (Pale or yellowish seedlings may indicate a lack of nutrients.)

Thin seedlings if you've sown them thickly.

DON'T

Start too early. Most seeds should be started four to eight weeks before they can be planted outdoors. Read the packet and follow sowing directions.

Use regular garden soil. It retains too much water, which can cause seeds to fail. Seedlings grow better in a lighter mix. Use a sterilized soilless mix designed for seed starting.

Rely on window light alone. The seeds will probably germinate, but unless you have a very bright window and turn the seedlings daily, they may grow tall and spindly. For sturdy seedlings, use a fluorescent shop light fixture with standard cool white tubes.

Overwater. Soggy seeds are more prone to disease.

NANCY ROSE