11 Tips For Protecting Your Plants This Winter

Cold weather is on its way but you’re not ready to let go of your tender garden veggies and flowers just yet. Is there a way to protect them from frost damage? Are there secret tricks to prolonging the harvest?

Absolutely! Season-extension methods are used by farmers to get the longest harvest window possible. These innovative and ridiculously simple methods for keeping plants cozy can extend your harvests by several months.

Keep reading to check out some of our top tips for keeping your garden cozy through the winter months.

Tips for Winterizing Your Garden

For growing zones 4 through 9, preparation is key to overwintering hardy crops. Tender annuals and flowering plants are the most susceptible to frost damage.

While your tomatoes and peppers probably won’t make it through the entire winter season you can certainly protect cold-tolerant crops like carrots, kale, broccoli, spinach, lettuce, chard, cilantro, cress, leeks, onions, radicchio, and frost-friendly perennial plants.

Most gardeners can employ a combination of these methods for added insurance against extreme cold. 

Mulch and More Mulch!

Mulch is the number one way to prepare your garden for winter. Just like insulation, mulch keeps the soil warm in the winter and cooler in the summer. It buffers roots from temperature extremes. It also suppresses any winter weeds that may pop up while you’re inside by the fireplace.

In a forest, nature mulches on her own when the leaves fall from the trees. Those leaves rest on the ground like a cozy insulating blanket for the soil. This protects the roots of more tender annuals and herbaceous perennials. As leaves break down, they also nourish the soil with rich organic matter for the following season.

You can mulch nearly any plant in the garden with as little as 1” thick or up to 6” deep of mulch. The most frost protective mulches include:

• Compost (best for veggies)
• Shredded leaf mulch (best for veggies)
• Shredded bark (best for perennials)
• Straw (best for garlic and larger veggies)
• Pine needles (for acid lovers)
• Wood chips (for perennials)

Key Caveat for Wet Winters

If you live in an area with extremely wet winters and your garden is prone to slug damage, you will want to keep mulch away from the base of your plants. As mulches like leaves or straw get soggy, they provide a breeding ground for slimy slugs. The moisture can also cause the mulch to harbor fungal diseases. You have a few options to prevent this:

• Keep a 2-6” ring of space around the base of slug-prone plants.
• Use fine wood shavings or saw dust near the base of plants.
• Use landscape fabric with holes cut in it as a mulch.
• Mix a small amount of coffee grounds into your mulch near the bottom of plants.
• For perennials, use cedar mulch because it is resistant to pests and pathogens.

Establish Plants Early

It is a common misconception that hardy crops can be seeded in cold weather. The truth is that young seedlings are the most susceptible to frost damage and death.

Even frost-hardy crops like kale or leeks stand no chance against extreme cold if they are too young. They need time to grow in mild temperatures so they can properly adjust to the cold.

It’s essential to establish your overwintering crops as early as 6-12 weeks before the cold sets in. This will allow the plants to grow robust root systems and slowly acclimate to the cold weather.

Use a Cloche or Recycled Bottle

A cloche is like a mini greenhouse that goes over a single plant. Some are large and bell-shaped, while others are recycled. Using a cloche dome protects your plant from wind, hail, and frost while also magnetizing more sunlight toward the plant and keeping any winter pests (like deer or rabbits) away.

Traditionally, cloches were made of durable glass. These old-time domes add an aesthetic charm to the garden. If you don’t want something breakable, you can purchase reusable plastic domes online.

If you enjoy recycling, use clear glass jars, plastic bottles, gallon jugs, or plastic fruit trays as reused cloches over small plants.

Bottles can be cut off at the bottom and pushed into the ground. Other shapes of containers can simply be turned upside down over your plants. If there aren’t any holes in the container already, it helps to poke a hole or remove the upper lid.

Use Row Covers

Row cover or row fabric is one of the most widely used tools on farms, yet so few gardeners take advantage of this budget-friendly, easy-to-use frost protection!

Row cover is a woven textile typically made of polypropylene or another synthetic fabric bland to trap heat, protect from wind, and keep pests out. When you lift up a piece of row fabric on a sunny winter day, you will be amazed by how cozy it feels underneath!

Row fabric comes in a variety of brands, sizes, and shapes. Most are white in color so plants can continue photoysnthesizing underneath. Depending on the thickness, they allow 30-90% sunlight transmission through the fabric.

Heavier fabrics provide more frost protection but let in less light, which means your plants will grow slower but hold more heat. The fabric is also permeable to allow rain and irrigation water to reach the plants (however, I recommend irrigating with drip irrigation lines underneath).

You can use row fabric to keep plants alive through the cold winters and to get an earlier start for spring growing.

As if row cover couldn’t be more miraculous, the best part is: Row cover can be used almost year round as long as it doesn’t get too hot. Thin row cover can protect from pests in the summer and thick row cover can be used throughout fall in winter.

You can easily toss it over your veggies when night temperatures start to cool. It can stay in place all winter long and you can pull it back to harvest from underneath.

Row covers have some downsides. First, they require securing. You need to secure row cover really well. If wind catches underneath the fabric, it will fly up in the sky like a giant piece of toilet paper.

The sides need to be weighted down. Do not push pins or landscape staples through the fabric or it will rip! Instead, secure the sides with rocks, bricks, or sandbags and add extra weight if you expect high winds.

Secondly, they need ventilation in hot weather. As a general rule, when temperatures get over 60°F in the day time, you may need to pull back your row covers and ventilate the bed so yoru crops don’t overheat.

Install Hoop Houses

A homemade low tunnel or hoop house is an inexpensive and easy way to protect an entire garden bed from the cold. You most of the benefits of a greenhouse without the cost or the huge space!

A mini hoop house is easiest to construct over raised beds, but you can do it in the ground as well. The main materials required are:

Measure the shape of your beds and the dome length across the top where the hoops will arch. Depending on the size of your beds, it’s usually recommended to put hoops every 2-4 feet.

Hammer rebar into the ground where each hoop will go, then slip a PVC piece over the top and arch it over until it reaches the other side. Then, pull your clear plastic tight over the hoops and secure with clamps as you go. When you’re done, weigh down the ends.

You should be able to undo just a few clips to fold back the plastic and access the bed when you need to work in it.

Prune Back Perennials

Many perennial plants like lavender, hostas, peonies, daylilies, and strawberries need to be pruned in the fall a few weeks before the first frost. This helps prevent frost damage and encourage them to channel their energy down into the root zone for the winter.

Although these plants are technically frost hardy, their foliage is actually quite tender. You don’t want bare strawberry leaves, buds, and crowns exposed to the frigid winter weather. Pruning also ensures that snowpack won’t break or snap off any large branches of the plants.

Other perennials like fruit trees, grapevines, and blueberries are typically pruned in late winter when the trees are barren. Some people wrap the bases of frost tender trees in burlap or frost blankets to protect from the biting winds and cold.

If your plants go through a deeper winter freeze, in many cases, it’s best to hold off and prune them in the spring after the freeze has passed.

Move Tender Herbs & Veggies to Pots

We transplant starts into the garden in the spring, so why not transplant older plants back into containers for the winter? If you adore your basil plants or are wanting to get a jump start on peppers next season, you can dig up the established plants and move them into containers for the winter.

As long as you are careful not to disturb the root ball, you have a much better chance of keeping tender plants alive indoors.

Generally, the process is the same for most garden crops. Use a shovel or trowel to dig a circle around the plant. Gently lift it from the soil and place in a pot that is at least 1.5 times bigger than the root ball.

Back fill the container and bring it indoors to a south-facing window or bright part of your home. Many plants slow down their growth in the winter, so you shouldn’t expect too much growth while indoors.

Instead, you are getting a jumpstart on next year’s garden. The main advantage is that you can move the plant back outdoors when the danger of frost has passed in the spring and enjoy earlier yields.

Insulate Container Bottoms

If you grow in a container garden, your plants’ roots are more susceptible to cold damage because they are lifted above the ground. This is especially true for small pots. They don’t have the insulating power of soil on their side.

To combat this, you can either bring them indoors or insulate the bottom of the containers to protect from frost. Some popular insulating materials include:

• Bubble wrap
• Burlap
• Old blankets
• Geotextile blankets
• Styrofoam

In mild-winter climates, there isn’t usually a need to wrap the entire plant. Instead, you can focus on keeping the root zone cozy so the plant can come back with a bang in the spring.

Water During the Day

Did you know that damp (not soggy) soil can hold up to 4 times more heat than dry soil? If you know that a hard evening frost is coming, it’s best to water your plants during the day.

This will provide an extra insulating barrier of thermal heat in the soil to protect the plant roots when temperatures dip overnight. This is especially useful for areas where winter temperature fluctuations can go from frosty nights to warm, sunny days.

Warm Plants & Tunnels With Water Jugs

Another clever way to use water’s insulating power to your advantage is with water jugs. Many greenhouse growers use big drums of water to add thermal insulation to their nursery tunnels.

Clear plastic jugs can accumulate a lot of thermal mass during the day while under the sun. At night, they can be placed near tender plants and actually radiate enough warmth to protect them from a light frost.

Choose Cold-hardy Plant Varieties

Certain plants have been bred to withstand the cold better than others. If you want a garden that yields through the winter and comes back in the spring, it is crucial to start with hardy varieties. Some of our garden favorites include:

• ‘Winterbor’ kale
• ‘Music’ garlic
• ‘Corvair’ spinach
• ‘Purple Top’ turnips
• ‘Austrian Winter’ peas
• ‘KN Bravo’ radishes
• Watercress
• ‘King Richard’ leeks

There are plenty of vegetables that you can grow in the fall, which are much more tolerant to cooler temperatures.