University of Vermont Extension 
Department of Plant and Soil Science

Spring News Article


STARTING SEEDS AND OTHER MARCH GARDENING TIPS

 
Charlie Nardozzi, Horticulturist and
Leonard Perry, UVM Extension Horticulturist
 
             
Organizing your seeds and starting many, pruning young leeks, and forcing shrub branches into bloom indoors, are some of the gardening activities for this month.

Organize seed packets by planting time. Some seeds are generally sown directly in the garden so should be set aside into one group.  These include ones such as corn, beans, and carrots.  A few flowers are often sown directly into the soil, including sweet peas and nasturtium.  I like to sow most of my seeds, even ones such as squash that can be sown directly, into peat pots or cell packs prior to get a slight jump on our usually short growing season.

Group seeds to be started indoors, then arrange them by planting time. For example, start with seeds that should be planted indoors 8 weeks before the average last frost, followed by those to be planted 6 weeks before, and so on. If you haven’t tracked, or aren’t sure of, your average last frost date, figure on perhaps mid-May in USDA zone 5, late May in zone 4, and early June or later in zone 3.  This date of course varies with your own more specific climate and year.

Some of the flowers you may want to start about 8 weeks from setting out include ageratum, coleus, dianthus, geranium, impatiens, ornamental millet, petunia, salvia, and annual vinca.  Wait until later to start most vegetables, although parsley might be started 8 weeks prior to planting out.  Many end up starting tomatoes too early, ending up with spindly and leggy plants.  Aim for about 6 weeks prior to planting for these.  More details on sowing dates can be found online (perrysperennials.info/pubs/oh89sowf.html and oh90sowv.html).
 
By starting your own plants, you'll save money and be able to grow unusual varieties not readily available in nurseries. Start seeds in flats filled with moistened seed-starting mix. Once the seeds germinate, place the plants under tube lights or grow lights (14 hours a day, 6 to 8 inches above seedlings), and keep soil moist.

If you started leeks indoors already, they are probably getting pretty tall by now. Trim them back to about 2 inches in height, so they don't get spindly and fall over. Like grasses, leeks grow from near the soil line rather than from the top, so you won't harm the growing point by trimming them back.

Prune branches and bring them indoors to force into early bloom. Prune flowering shrubs such as forsythia, quince, mockorange, deutzia, and honeysuckle.  Tree branches easily forced include crabapple, apple, cherries, serviceberry, and of course pussy willow.  Some like to soak branches in a bathtub overnight.  Trim the branches to a reasonable size for your vase.  Place in water, and you should have flowers in 2 to 4 weeks for many of these.

March also is a good time to prune fruit trees.  Choose a day above freezing if possible, as it is easier on you as well as on the tree.  First, check for and remove the 3 D’s—branches that are dead (usually a different color), diseased (look for scabs or spots), and damaged (as from ice damage or wind breakage).  Then check for and remove the 2 C’s—branches that are crowded or crossing (they’ll rub on each other, wearing off the bark where disease can enter).    Finally, prune selectively, shaping the tree according to its age and type of fruit tree.

(Charlie Nardozzi is a nationally known horticulturist, author, gardening consultant, and garden coach; CharlieNardozzi.com).

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