University of Vermont Extension 
Department of Plant and Soil Science

Spring News Article
Charlie Nardozzi, Senior Horticulturist
National Gardening Association, and
Dr. Leonard Perry, Extension Professor
University of Vermont
Sowing cole crops, forcing pussy willow twigs indoors, and fertilizing houseplants are some of the gardening tips for this month.

Cole crops, such as broccoli, cauliflower, and cabbage, can be started over the next couple of weeks indoors under lights. These cool-loving crops will grow six weeks indoors before being transplanted outdoors two weeks before your last frost date. Keep seedlings moist and well fed to get the sturdiest transplants.

In the next few weeks pussy willow buds will begin swelling, so go on a scavenger hunt for them in wet areas. Take two-foot cuttings from the bush, trying not to deform it by taking too many cuttings in one location. Bring them indoors and place them in water in a cool room.

Now that the days are getting longer, your houseplants will be resuming vigorous growth, so begin fertilizing with a soluble fertilizer. A seaweed or fish emulsion blend is a good choice -- but look for one labeled as "no odor" to avoid the usual pungent smell. You can fertilize monthly at the label’s recommended rate, or fertilize every time you water using one quarter-strength.
Check seed packets for recommendations, then plot out planting times for seeds you'll be starting indoors. Don't try to get a jump on the season by planting earlier; larger plants are more easily stunted than smaller ones and won't necessarily grow faster once they're transplanted outdoors.

If you left your ornamental grasses intact last fall, you can go ahead and prune them back to a height of about 6 inches. If you remove the old growth before new growth starts, you won't risk damaging new sprouts. Add prunings to the compost pile.

Spray horticultural oil on fruit trees, such as apples, plums, and cherries, to smother any overwintering insects. Choose a calm day when temperatures are above 40 degrees F, and be sure to cover all sides of the branches. You can also apply it to evergreens to control spider mites and other insects. Carefully follow the instructions on the label for proper usage and plants.

Cold frames are handy for hardening off seedlings. You can make a simple cold frame by placing hay bales along the perimeter of a rectangle, and placing old windows or a glass storm door over the top. Purchased cold frames are convenient, and some have thermostatically- controlled tops that open automatically when the temperature inside hits a designated point. Since the midday sun can heat a closed cold frame up quickly, this feature is especially handy if you're away for long stretches during the day.   

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