You can have your winter herb garden survive until spring when you follow a few steps for success. Learn the principles to help plants thrive and survive when it is cold outside.
One of the problems in the first years of herb gardening comes at the approach of fall. It can be a guessing game to know what to leave, what to bring indoors and what to mulch. Fortunately, most herbs are hardy perennials and need no winter protection beyond a watchful eye.
“To walk among the herbs on a late November day is an adventure.” Adelma Grenier Simmons Herb Gardening in Five Seasons
If you live in an area with distinct seasons, there are natural limitations to when you can grow herbs outdoors. Before you know it, the shorter days and cooler temps of winter will return to signal the end of your outdoor growing season.
Of course, it’s difficult to fight Mother Nature, especially if you hope to win. However, if you learn to work within the boundaries she sets, you can find successful ways to extend your herb growing season.
What Kind of Herbs Do You Have?
Familiarize yourself with the herbs in your garden and whether they are annuals, perennials, or biennials. Then putting your herbs to bed for the winter will be less of a puzzle, and you will have only minor plant loss in the spring.
Annuals do not return from the root next year. The primary annuals grown in the herb garden are basil, chervil cilantro, chamomile, pineapple sage, calendula, and stevia. These herbs should be harvested before the first frost and can be dried for enjoyment in the kitchen using one of these three herb preservation methods.
Biennial herbs take two years to complete their lifecycle from start to seed. These plants, which are often grown as annuals are dill, parsley, summer savory, bay laurel (depending on your zone), and some of the sage varieties. Your best bet for winter survivability with biennials is to harvest what you can and mulch the plant. We’ll talk more about them below.
Tender perennials are plants that will survive to see another year, but maybe not in your northern garden zone. These are plants like lemon verbena, and some of the lavender varieties, that do well overwintering in warm climates, but not in zones 3 to 7.
Herbaceous perennials are plants that come back from the same rootstock year after year. They lose their leaves once frost hits. You’ll find they are the backbone of your garden and will give it the most interest during the winter months when the vegetable garden is long gone.
For the kitchen garden, these herbs are oregano, mint, thyme, tarragon, chives, lavender, and rosemary. You’ll find that almost all medicinal herbs fall into this category too.
Stop the Damage that Frost Can Bring to Your Winter Herb Garden
While you can’t prevent early blasts of winter, you can stop some of the damage caused by a seasonal freeze. You simply have to be prepared to provide adequate protection for your tender plants when the need arises.
Adding a heavy layer of mulch is the easiest way to provide protection for your plants. Mulching around your plants provides a layer of insulation for the soil when temperatures dip too low. It will also help hold in moisture as temperatures rise so you won’t have to water as much.
There are many types of mulch available, including shredded leaves, wood chips, grass clippings, straw, and compost. Whatever type of mulch you choose for your winter herb garden area, check to make sure it is free of chemical pesticides and herbicides. For example, if you use a lawn service to keep your lawn green and free of weeds, you wouldn’t want to use your lawn clippings on your herb garden.
Cold frames are another great way to extend your growing season. A cold frame is simply a four-sided structure with a glass or plastic lid on top. While often used for vegetables, they work well to extend the life of your winter herb garden too. It is worth your time to build a frame and trap in some of the heat from the sun. This will keep plants warm when temperatures begin to drop.
Cold frames are relatively easy to build. Start by creating a rectangular or square structure out of wood and securing an old glass window or door on top with hinges on one side. This will keep the top from blowing off in the wind and will make it easy to open and shut as you add and remove plants. Potted plants and seedlings can then be placed inside to harden them off or help them survive unexpected dips in temperature.
In a pinch, you can create a makeshift cold frame with several bales of straw and an old glass window or door panel. Simply arrange the bales in a rectangle, while leaving the interior empty to house your plants. Top with a window or glass-paneled door and securely weigh it down on both ends so it doesn’t fly off in high winds.
If neither of these options appeal to you, you can always buy a ready-made version (Amazon link) at your local garden center or online. You’ll pay more for this option but won’t have to go through the hassle of finding materials or investing the time to build it yourself.
For many gardeners, a greenhouse is the ultimate gardening dream. How great would it be to have a permanent year-round space to nurture and grow your favorite plants? As an added bonus, a well-designed greenhouse can serve as a beautiful focal point for your property, as well.
Unfortunately, hiring a contractor or purchasing a high-end kit to build a permanent greenhouse can get pretty expensive. Plus, you need to pay to heat the structure part of the year in colder climates. If you rent or have limited outdoor space, a permanent greenhouse may not be a viable option.
However, you can still enjoy many of the benefits a greenhouse offers without the high price tag or long-term commitment. There are a number of very affordable and portable mini-greenhouses (Amazon Link) available that are lightweight and have a small footprint. These options take advantage of vertical space by providing four or five substantial shelves to house your plants.
With a little planning, these three methods can extend your herb harvest season. Once you get started, you may be surprised by how much more productive your winter herb gardening efforts become!
You Can’t Stop a Hard Freeze
Unfortunately, you can’t always stop Mother Nature from doing her thing, and some years despite your best efforts, the winter herb garden will succumb to a killing hard frost. When freezes stick around for several days or weeks, you will likely lose your plants. This actually happens more in the South, where plants are not used to cold weather than it does in the North.
In my Oregon garden, the herbs would survive all but the harshest of winter cold. Mulching, and in extreme cases, wrapping the plant in clear plastic would be enough to get them through extended cold snaps. Here in the South, the herb plants don’t seem to be as hardy. Because they are not used to cold weather, they will need extra protection – or need to be brought inside – when the weather turns.
For related content, join me over at Minnesota Country Girl where I have the privilege of guest posting for Homestead Winter Prep: A Series of Harvesting & Preserving!