Spring has truly sprung and it’s an early one this year. With all this sunny weather it’s tempting to dive right in and start planting all those beautiful flowers and yummy veggies in the garden. Many native plants and trees are even starting to leaf out and might be green by the time you read this article.
But hold on.
The nights are still cool, dipping down to 35 or so and it’s possible it could still freeze. Most plants don’t appreciate these cool temperatures and will even die.
However, it’s the perfect time to do all those other garden projects and preparations. Turn those garden beds, adding lots of compost and manure. Chicken, horse and cow manure need to be composted but duck and rabbit manure can be added fresh (though manure with lots of straw or sawdust bedding in it should still be composted). Cover the veggie beds with weed-block and plan out your patch. Get a jump on weeds by weeding and mulching flower beds. Prune your fruit trees and trim blackberry bushes, rose bushes and tidy the raspberry bed by removing spent (dead) canes. It’s also the perfect time to divide perennials.
If you just can’t resist planting, there are some seedlings that can handle a bit of a chill with no ill effect. These include the cabbage family like broccoli, kale, cabbage, kohlrabi and cauliflower. Other plants that don’t mind cool temperatures, just as long as it doesn’t actually freeze, include parsley, celery, green peas, lettuce, spinach, Swiss chard and potatoes. Corn and onions are surprisingly resilient too, as long as they are well sprouted. Radishes do okay if the days are warm. Flowers including pansies, violas and calibrachoa can handle some nip in the air, although their blooms might suffer.
You can take measures to protect more tender plants by putting them in a cold frame or covering them at night with a light fabric like reemay to insulate them. This can increase the temperature by two to four degrees and make it possible to plant earlier.
Plants to avoid until it’s at least 48 degrees include zucchini, summer squash, green beans and most annual flowers like begonias, petunias and fuchsias.
So when is it time to plant? Your best bet is to watch the weather. This doesn’t necessarily mean the forecast on your weather app as the predicted temperatures can vary wildly from app to app and the nightly lows are not necessarily what occurs. Get a high/low thermometer and monitor each night’s low. When night time temps don’t dip below 42 degrees you’re good to go. This is usually about the second week of May, around Mother’s day. Visual signs to look for in your micro-environment usually include alders and other deciduous trees starting to leaf out and dandelions blooming. This year, however, I would use caution and keep a careful eye on the forecast for unusually cool nights.
As always, remember to harden off starts before planting them outside. You can do this by putting the starts outside during the day and taking them in again in the evening for several days in a row.
Good luck and happy planting,
Blythe Carter owns and operates Blythe’s Garden.