Planting Guidelines for Spring: Northeast

There are challenges to gardening in the Northeast. But if you know when — and what — to plant, you can have a harvest worthy of a Thanksgiving dinner. To reap this success, though, you must make sure the soil is suitable and that there's no chance of frost. And, quite simply, you have to plant the right crops and flowers for your zone (can anyone say blueberries, tomatoes, tulips and corn?).

Gardening in the Northeast states is defined by its winters, but that doesn’t mean that beautiful, bountiful vegetable and flower gardens aren’t possible. It just means that gardeners, especially in the New England states, should prepare for a short growing season and know how to maximize it.

“When you are gardening in New England, you have to consider the winter first,” said Michael Arnum, marketing and public relations director for Tower Hill Botanic Garden in Boylston, Massachusetts. “You are going to have six months of dormancy.”

Steve Jones, owner of Mettowee Mill Nursery in Dorset, Vermont, agrees with the adage of not planting until after Memorial Day. “You can certainly still get frost in April and May here. You can start preparing the soil in late April or early May and, if you want to chance it, start your planting then. But we do get frost that late in the season. You have to be a pretty hardy plant to be in this zone.”

However, some areas within the Northeast states also have slightly milder — and shorter — winters, which add a few weeks to the growing season.

“You really need to pay attention to the planting zones,” said Dr. Chris Sacchi, a professor in the biology department in Kutztown University in Kutztown, Pennsylvania. “For instance, my brother in upstate New York starts his garden a few weeks later than I. I use May 11 as the last frost date, and on average, that’s pretty accurate. Of course, elsewhere in the Northeast and New England states, they tend to plant after Memorial Day. Some of my neighbors plant in late April, but they are taking a risk.”

The USDA recently released new plant hardiness zones that represent the average annual extreme minimum temperatures at a given location during a particular time period, which are a good gauge as to when — and what — should be planted and the length of the growing season.

Under the new zones, the northeastern states range from 3b (-35 to –30 F) in the coldest parts of New York, Vermont, New Hampshire and Maine to 7b in southern New Jersey (5 to 10 F).

Along with the diversity of its temperatures, the region has a variety of soils. In the New England states, it tends to be rocky and sandy, while in New Jersey, Pennsylvania and New York, the soil is more clay or limestone based.

“You can find slivers of clay in the soil around here, and that doesn’t hold water very well,” said Ginger Pryor, master gardener coordinator at Penn State University. “Soil testing is important, and it’s probably a good idea to put at least 5 percent organic compost in it.”

Arnum says prepping a New England soil is long-range activity. “It’s very rocky, so over the years you will be able to cull out the large rocks and add lime and organic matter to make it a richer soil. It takes time.”

Another interesting diversity within this region is the amount of sunlight. In the northern regions, the sun could shine for 14 to 16 hours during the summer. “The quality of the sun is different than for states closer to the equator,” Jones said. “It affects plants like onions. We may have long days, but our direct sunlight may only be six hours.”

By paying attention to the growing season, gardeners should have success with a number of crops, particularly root crops. Broccoli, cauliflower, green beans, beets, lettuce and cucumbers grow well. Crops that are tougher to cultivate are cantaloupe, asparagus, okra, melons (of any sort), strawberries and peppers, says Barbara Murphy, extension educator for the University of Maine.

Flowers, such as impatience, begonias, lilacs, crabapple trees and peonies, thrive in this area. “I try to always have a blooming plant or two in my garden,” said Sacchi. “I start with crocus, Lenten rose, ornamental strawberries, golden Alexander, irises, cardinal flower and black-eyed Susan. They all work well here.”

Bulb flowers, such as tulips or daffodils, do especially well. “They need that six months cold dormancy,” said Arnum. He suggests planning bulbs in the fall when nighttime temperatures stay between 40 and 50 F. He also suggests to plant at least six weeks before the ground freezes so as to allow enough time for the bulb to start rooting. If the soil contains a lot of clay (it will puddle up after a good rain), add sand and compost. After the first freeze, cover the bulb beds with a lightweight mulch that will maintain a consistently cool soil temperature.

Many of these bulbs, such as the daffodils, tulips, calla lilies, tuberose and iris, are also welcomed for another reason — the deer don’t like them. “Deer will eat just about anything, and it’s very frustrating to have a great vegetable or flower garden and lose it to the deer,” said Sacchi. “And in these parts of the country, the deer are everywhere — even close to a lot of suburban neighborhoods.”

Also unwelcomed to Northeast gardeners is a new pest — the brown marmorated stink bug. Introduced from Asia, this bug has gone from a nuisance to a real problem for orchard growers.

“They came into Pennsylvania about five years ago, and they love food — fruit, peppers, tomatoes, sweet corn,” said Pryor. “There isn’t much that we’ve found that can get them — certainly nothing organic seems to work. They secrete an enzyme that turns a tomato white and the corn black.”

Despite the challenges of clay or sandy soil, long winters and shorter growing times, gardening in the Northeast can be rewarding — especially if you remember a truism about gardening and renewal. "If something dies," said Sacchi, "stick a new plant there and let it earn a place in the garden.”

Where's the Best Place to Buy Plants?

“People talk about killing plants,” said Dr. Chris Sacchi, a professor of biology at Kutztown University in Kutztown, Pennsylvania. “I say, don’t worry about the plants that died; worry about the plants that are living. Everyone has failures. Buy plants from local nurseries or farmer’s markets. They have the plants that will do best in your area.”

As the planting season revs up, gardeners have a variety of retail options — nurseries, hardware stores, big-box stores, farmer’s markets, online — and gardeners may not know what is the best option. To maximize success, buy plants that are suited for your area and from people who can answer any questions about growing locally.

Shopping at local farmer’s markets is an excellent place to buy plants of high quality, Sacchi notes. “Local nurseries and greenhouse businesses are also great sources of quality plants and advice about plants that will succeed in your area,” he said. “I'm a great believer in supporting locally owned businesses, not only for the benefits to the owners and employees who are residents of the community I live in, but also because there is a great deal of experience and knowledge about gardening that the owners and employees of these businesses can share with customers.”

However, many online nurseries also are knowledgeable about local growing conditions and the most suitable plant options. “Our customer-service representatives have a huge database of information that can answer just about any question a customer may have,” said Brad Carman, a master gardener with Spring Hill Nurseries in Tipp City, Ohio. “We know what are the best plants, and our website talks about planting zones and has gardening tips. You can go into these big-box stores, and the person working in the nursery may or may not have any experience or education in gardening.”