Dr. Vern Grubinger, Extension Associate Professor
University of Vermont
March is often a difficult month for gardeners. It's not really winter--the time to dream about and plan the garden, and it's not yet spring--the time to plant. But in this in-between month, there are a few activities for gardeners to do.
Probably the biggest gardening project for March is to start transplants. Cabbage, broccoli, and other cole crops that can be set out early in the spring, as well as slow-growing flower varieties like verbena, pansies, and petunias, can all be started this month. But wait until April to sow seeds for tomatoes, peppers, eggplants, and most flower varieties that cannot be transplanted until the danger of frost has past.
Check the seed packet to determine if the seeds can be started indoors or should be sown directly in the ground when the weather warms up. Starting seeds indoors not only gives you a jump on the growing season, often leading to earlier harvests, but also helps with weed control because the crops get a head start on the weeds, too.
Knowing when to start seeds in time for outdoor planting can be confusing. One easy way to calculate this is to get a calendar and count backwards from the date the plants can safely be transplanted. For many vegetable and flower varieties, plan on six to ten weeks between starting the seeds and planting outdoors. However, crops vary widely in this regard. Check seed catalog descriptions and packet instructions carefully to assure that plants are ready to set out at the right time.
Ideally, seeds need 70 to 75 degree F temperatures to germinate, and 60 to 65 degree F temperatures to grow. If you are starting and growing plants in a cooler environment, allow more time for the transplants to be ready to set out. As soon as the seeds emerge, provide 14 to 16 hours of light a day to keep plants from getting leggy.
Plant seeds in a soil-less growing mix that has a peat moss base (available at garden centers). Mixes that contain soil often lead to damping off, a fungal disease that kills the seedlings. Thoroughly wash your used plastic seed starting containers with clean water. If you have had disease problems in the past, it's advisable to use a mixture containing 10 percent household bleach and water to sterilize them.
It helps to wet the soil-less mix before filling trays since it is does not absorb water easily when dry. Instead of using plastic trays, you can use individual peat pots. Or make your own "soil blocks" out of potting mix using a small scale block maker available from organic gardening supply catalogs. Both of these can be planted directly into the garden, thus avoiding the need to clean plastic containers. They also help prevent transplant shock since roots are not disturbed.
Use this "down time" to inventory your garden tools and repair or replace as needed. Sharpen shovels, hoes, and lawnmower blades. Oil moving parts of pruning shears. Take your lawn mower to the dealer for a tune up. And don't forget to order compost, fertilizer, and other soil amendments to have on hand for spring soil preparation.
Inspect stored dahlia, gladiolus, and begonia bulbs for signs of shriveling or rot. Discard dead or decaying bulbs. You can get a head start on the season by potting up any of these tubers, with the exception of glads. Keep bulbs as cool as possible for roots to grow before tops start, except for tuberous begonias, which like it warm. Any potting medium will work. Once tops start, lightly fertilize.
Other activities for March: prune fruit and ornamental trees, blueberry
bushes, and summer-flowering shrubs before buds begin to swell; buy a shamrock
for St. Patrick's Day; start saving plastic milk jugs, newspapers, and
burlap to use as frost protectors in the garden.