April Gardening Tips

Monthly Proven Tips and Solutions for Granite State Gardeners

Photo by Sigmund on Unsplash

Once the snow melts, you may be dismayed to find damage to your lawn or landscape plants due to the activity of moles and meadow voles, both of which are active year round.

Meadow voles create unsightly, round, grassy tunnels on the surface of lawns, but do more lasting damage to woody plants by chewing their bark. If you see lots of vole tunnels in your lawn take a close look at the base of your trees and shrubs. Vole feeding often girdles branches, trunks, and roots which can kill trees and shrubs if damage is excessive. Moles create hills and tunnels in the lawn by pushing up the soil as they forage for insect larva and earthworms. Their activity usually looks more serious and damaging than it truly is and be fixed by tamping down or raking out tunnels.

Remove winter protection from perennials and shrubs.

Rake away winter mulch and take off burlap wrappings. Once the snow has melted, excess mulch piled over the crowns of perennials can delay soil warming and slow down the emergence of new shoots. Burlap wrappings on shrubs can be taken off evergreen shrubs once spring bulbs begin blooming. If burlap was used to prevent deer damage wait to remove it until wild herbaceous plants start to put on new growth in the spring. Deer tend to ignore shrubs once more nutritious food sources are available.

Install birdhouses to entice songbirds to nest on your property.

Although not all songbirds will use birdhouses, species that nest in cavities such as house wrens, Eastern bluebirds, black-capped chickadees, and tree swallows will often use birdhouses that have been properly constructed and placed. Birdhouses should be set up by early April before the start of the breeding season to get birds to use them.

Wait to fertilize vegetable garden beds until right before planting.

Fertilizer that is applied too soon may leach out of the soil before plants can use it. If you are using slow-release fertilizers, the entire amount of fertilizer that you need can be applied right before planting. If you use a synthetic or quick-release source or nutrients, apply one-half of what is needed before planting, and the remainder 4-6 weeks later alongside plants or around plants as a “side-dressing.”

Plant cool-season crops in the garden.

Plant cool-season crops in the garden. Cool-season crops are vegetables that can be planted before the last frost. They are not only cold tolerant but grow best under cooler temperatures. They may even be of poor quality once hot weather arrives. For example, radishes get tough and distastefully strong tasting in the heat of the summer. Common cool-season vegetables include spinach, turnips, onions, leeks, carrots, broccoli, kale, brussels sprouts, peas, swiss chard and beets.

Start seeds of warm season flowers and vegetables.

In Zone 5, where most New Hampshire residents live, the last frost is typically in late May. That means you can anticipate planting your tender flowers and vegetables in the garden around Memorial Day. Of course, this is not a hard and fast rule and you should always pay attention to long-range forecasts. If you want to start tomatoes, the package will direct you to start the seeds indoors six to eight weeks before the last frost. If you want to plan to transplant your flowers and vegetables into the garden on May 27th, then you would start your seeds between April 1st and April 15th. Cucumbers can be started four to six weeks before planting date, while peppers and eggplant may require at least 10 weeks of time indoors. 

April is usually the time to treat lawns for crabgrass with pre-emergent herbicides.

Prime crabgrass germination occurs when the soil temperature is above 55℉ at a depth of 1-2 inches for at least four or five days. This is typically around the time that forsythia is in full bloom. Pre-emergence herbicides should be applied around this same time or even slightly prior to peak bloom. They need to be on the ground before germination takes place in to work properly. If the application window is missed, the only remaining options are to hand-pull the crabgrass or to apply a post-emergent herbicide, the latter of which is not nearly as effective as pre-emergents. If using an herbicide, make sure to read and follow all instructions on the product label. And remember, establishing a dense and healthy lawn is the best way to keep crabgrass and other weeds at bay. Herbicides can be useful tools, but they will not entirely keep the crabgrass away.


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Author(s)

Emma Erler
Landscape and Greenhouse Field Specialist
Instructor Field Specialist
Phone: 603-641-6060
Office: Cooperative Extension, Taylor Hall, Durham, NH 03824

Ask UNH Extension
Master Gardeners & Extension Specialists
Phone: 1-877-EXT-GROW (1-877-398-4769)