March 7, 2005

As the vernal equinox approaches the days are getting longer. The angle of the sun is also changing, appearing higher in the sky each day. With these changes more light becomes available. The plants respond with more vigorous growth.

When the houseplants start to put out new growth you can resume a feeding schedule. A water-soluble fertilizer can be applied once every two weeks. They may also need to be watered more frequently as vigorous growth resumes. Re-pot any plants that are showing signs of being crowded in their container. New roots need room to grow. Check the roots by inverting the pot and slipping the plant out. If the roots are encircling the soil or there is very little soil visible, then re-pot the plant in the next size container.

It may be a few weeks before we can get outside to do any planting. The forecast is not favorable for an early spring. As soon as the ground can be worked seed of peas, lettuce and swiss chard can be planted. But these can all be planted in April as well.

While you are waiting for the planting to begin tend to some yard and garden clean up. Pick up any fallen branches and debris, composting the smaller pieces. Some weeds are already visible in the garden beds. Many perennial weeds will begin growing now as well as some winter annuals such as bittercress. These can be pulled up on a mild day as the soil thaws.

Don’t be too anxious to remove burlap wind barriers from the broadleaved evergreens. March is a windy month, best to wait until next month to take them down. The same goes for winter deer protection. The trees and shrubs that they rely on to get through the winter need protecting until non-woody material becomes available.

When the temperature is 40 degrees or above, apply a dormant oil spray to fruit trees and deciduous trees and shrubs. The oil spray smothers over-wintering pests. This is a good defense against lacebug and scale insects. Broadleaved evergreens such as azaleas and rhododendrons can also be sprayed. Some needled evergreens and ferns are sensitive to the oil however. Always check the label warnings before applying to these plants. If in doubt, first try spraying on an inconspicuous spot as a test.

March is the month to prune back butterfly bushes. They benefit from severe pruning, 6-8 inches above the ground. The bush will put on healthy new growth with more flowers. Cut them back at least every two years. Lavender plants also respond well to a late winter pruning. Cut back the ratty stems to a couple of inches above the ground. The lower buds will then grow into sturdy plants. Some varieties of lavender are not hardy to our zone 6. If you are losing lavender plants every winter, you may be growing the tender ones. The varieties Hidcote and Munstead are both hardy in New Jersey and reliably come back each spring.

March is also the month to cut down the ornamental grasses. You want to do your trimming before the new shoots start to grow. If you wait too long it is difficult to prune the old foliage without cutting off the tips of the new shoots. The plants will look as if they have been to the barbershop, but they will green up quickly with the return of warm weather.

Seedlings started indoors for early planting should be thinned when the plants have at least two sets of true leaves. In seed starting trays with individual cell compartments there should be only one plant per cell. Growing more seedlings per cell makes weak plants. In trays without compartments allow a couple of inches between plants. If planting out doors is delayed due to cold or wet weather and the seedlings are growing out of their little cells, transplant the seedlings to larger containers. A weak fertilizer solution can also be applied.

A week before planting the seedlings outside, start acclimating them to out door temperatures and wind. Set them outside in a sheltered spot during the day. A few days before planting leave them out overnight.

There are approximately ten weeks until the average last frost date. Seeds for peppers and eggplant can be started inside now. Seeds that only need 6-8 weeks of growing indoors, such as tomatoes and basil, can be started at the end of the month or the first week of April.

Beth Nardone, botanist, is a resident of Hillsborough and is the Nursery Manager at the Belle Mead Co-Op.  Questions and comments can be sent to bethtanical@patmedia.net