Start Seeds, Build a Cold Frame, Check Fruit Trees: March Gardening Tips

By Guest Authors Charlie Nardozzi, Horticulturist and Leonard Perry, UVM Extension Horticulturist.

In early March, snow may still be covering your garden. But rest assured, spring is just around the corner, and there’s much to do to get your garden ready for the growing season. Horticulturist Charlie Nardozzi and University of Vermont Extension Horticulturist Leonard Perry give us some gardening tips for March.

March care for fruit trees

Spray horticultural oil on apple, plum, and cherry trees to smother any overwintering insects. These are often called “dormant oils” as they’re applied while trees are still dormant, just before buds emerge. Choose a calm day when temperatures are above 40 degrees (F), and when no rain is forecast. Be sure to cover all sides of all branches, including inner and upper. Carefully follow the label instructions for proper usage and appropriate plants.

Build a cold frame

Cold frames offer a great opportunity to get a jump on the growing season and start your plants with real sunlight instead of indoor grow lights. 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. You can also purchase cold frames, some with thermostatically-controlled tops that open automatically when the temperature inside hits a designated point. Since the midday sun can heat this space up quickly, a vent is especially handy if you’re away for long stretches during the day. Check seed catalogs and online garden suppliers for the many types and price ranges of cold frames.

Start seeds for cool weather crops

Cole crops such as broccoli, cauliflower, and cabbage can be started indoors now under grow lights. These cool-loving crops should be grown for six weeks indoors before being transplanted outdoors about two weeks before your last “average” frost date. Keep seedlings moist and well-fed to get the sturdiest transplants. Lanky, tall seedlings will be a sign they’re getting too much fertilizer, too little light, or both. If you don’t have a cold frame, set mature seedlings outside on above-freezing days so they’ll “harden off” and get stockier.

Plan crop rotation in your vegetable garden

Crop rotation is key in keeping diseases and infestations at bay and not depleting the fertility of your garden soil. When planning your vegetable garden layout, avoid planting members of the same plant family in the same spot they were in last year, or even the year before. Members of the same family are susceptible to the same diseases and insect infestations. For example, avoid planting members of the tomato family (tomatoes, potatoes, peppers, and eggplant) in the same place year after year. You may rotate these crops with other families such as the legumes (beans, peas), cabbage (cabbage, kale, radishes, turnips), or the cucurbits (cucumber, melons, squash).

If you’re growing strawberries and raspberries

Check strawberry plants twice a week for signs of new growth. As soon as you see sprouts, remove the straw mulch and spread it in the rows to help control weeds. A top dressing of an inch or two of compost will give plants a boost.

If you’re growing raspberries, spring is the time to prune shoots before new growth begins if you didn’t prune after harvesting. If growing the “everbearing” or two-crop types such as ‘Heritage’ or ‘Fall Gold’ for a fall crop, you can prune all shoots to the ground. Summer-bearing types produce fruit on canes from the previous year, so don’t prune these out or you won’t have any fruit. Prune out canes that fruited last year, usually those more woody, light in color, and brittle. For any type, prune out canes that are weak and spindly, leaving healthy canes 6 inches or so apart.

A version of this article originally appeared on the University Of Vermont Extension website.