How To Protect Your Plants From Frost And See Them Bloom

Winters are a time for mugs of hot chocolate, snuggling under warm blankets, and enjoying the toasty warmth emanating from one’s hearth. However, winter may spell trouble for gardening enthusiasts in terms of plants that are vulnerable to frost. If you’re on the edge of your seat worrying about your tender plantshealth this coming winter – we’ve got some excellent news. Your rosemary, kale, chives, parsley and all your other plants will be safe! 

Flower on a pot covered with white frost

You may already know how to wrap your olive trees for winter. It’s time to find ways to do the same with your plants. There are several handy techniques you can adopt to safeguard your outdoor plants from cold weather. These include utilising cold frames, moving potted plants indoors, etc. Our plant-centric article will focus on helpful tips to guarantee your plants’ safety from the frost and cold air accompanying cold temperatures. All you need to do is grab a comfy seat and stay with us as we simplify plant care and maintenance in winter!

Why worry about frost and when to expect it?

Before we discuss the precautions you can take to protect your garden plants and vegetables from the threat of frost – let’s focus on why it is a concern to begin with. 

Firstly, frost causes ice crystals to develop in plant cells, which can damage your plants. That’s because the development of ice crystals can obstruct the movement of fluids (aka osmosis) and diminish the water available for plant tissues

Plants are categorised according to the temperatures they can tolerate. Some of them are hardy – meaning they can get by when there’s short-term freezing. Conversely, others can be severely injured or die in freezing temperatures.

Some examples of such plants include succulents, begonias, cucumbers, etc. That’s why we recommend you do some in-depth research about the hardiness of the plants and vegetables in your garden to be better prepared for the danger

As to when you should expect frost – it’s best to listen to the weather forecasts for warnings in early fall and late spring. That’s the best way to ensure you’re prepped to protect the plants that need saving. Believe it or not, frost doesn’t require extreme freezing temperatures and can occur in ones ranging from 0 to 2˚C. What’s more, it may be sorted into two categories: light frost and hard frost

Roses in garden with white frost

Light frost occurs when the weather drops below freezing temperatures for just a few hours. This type can end up killing the upper parts of plants while the lower ends remain green. On the other hand, a hard frost is when the temperatures drop below 2 degrees Celsius for a time, turning the air cool and the ground hard. It can kill all plant parts that are above surface level

Additionally, you should also note that temperatures below 0˚C have the capacity to be more destructive than frost itself. Tender plants like houseplants can be killed off relatively quickly when the temperature drops so low for a few hours. 

So, when you hear about a freeze warning in spring – be quick to bring your plants indoors. In comparison, a freeze warning in the fall should alert you to the growing season‘s end because temperatures are low enough to kill annual plants and prompt inactivity for hardy plants like perennials, shrubs, etc.

Which plants need frost protection

Typically, annual plants that need warmth to flower/fruit are the most vulnerable to cold temperatures. So, vegetables or herbs that you harvest in midsummer or plants that flower during the same time can all classify as frost tender plants

That means they need to be protected from frost damage, be it in the fall or during the spring. In fact, a quick search will reveal that most of these plants are native to tropical areas – meaning they require frost-free settings to remain healthy. If your garden includes such plants, it’s a good idea to start taking measures to protect them when the weather dips below 4˚ Celsius

On the flip side, perennial garden plants may survive a sudden dip in temperatures – as long as they’re healthy and have no other underlying concerns. However, note that a spring freeze can still cause damage to flowers or fruits. 

Now, let’s talk about the edible variety of plants. Veggies like onions, lettuce, radishes, etc., are pretty hardy and sustain themselves even when the weather drops as low as -3˚ Celsius. Then there are vegetables like carrots, Brussel sprouts, spinach, and others that can tackle temperatures such as -6˚ Celsius. 

How to protect your plants from frost in simple ways

So, are you ready for some solutions? Here’s a list of different methods you can try to protect your wonderful plants:

1. Site selection is important

When it comes to prepping your plants to survive the winter – site selection can matter a great deal. Details like soil characteristics, elevation, the lack of adequate coverage, etc., can all matter when it comes to heat emission

It’s also best to plant tender plants near a south-facing wall (or a west-facing wall) and avoid open areas exposed to the elements. This will ensure your plants receive warmth from the structures nearby that absorb heat in the daytime and emit it at night. 

White wooden cold frame protecting young plants from frost

2. Use a cold frame

You can protect your vulnerable plants from cold snaps and dipping temperatures by constructing a cold frame. If you’ve never heard of them, they’re simply box-like casings without a bottom. You can place them over your plants in the garden to protect them from the cold. These frames feature a transparent roof to allow the sunlight to stream in and a hinge to allow for the top to swing on. 

They are also ideal for retaining heat – which helps gardeners extend the gardening (or growing season) in spring and the fall. 

3. Bring out the blankets

You can make use of old blankets, drop cloths, bed sheets, etc., to help create a sheltered spot or environment for your plants. 

Drape the material over plants gently and use stakes to act as support. However, you must cover plants completely; the material extends to the ground and creates a type of insulation bubble

If you also encounter strong winds, use something heavy like bricks or stones to hold the material to the ground. Use a plastic polythene cover to protect the fabric from rain, drizzle, or dew. However, if you do use a plastic cover to protect your fabric tent, remove the plastic covering by the time the sun’s at its peak (noon) to avoid the chances of overheating. We’d recommend using woven fabrics because they tend to retain heat better and provide better insulation

A new plant covered by plastic cloche

4. Cover with cloches

Gardeners can turn to garden cloches for an easy way to protect individual plants from frost. You can create a greenhouse-like environment by placing one over your plants. 

Another pro-tip is to use milk jugs to create DIY cloches at home. Start by cutting the bottom off a litre-jug and use it to cover the plant by pushing the edge of the jug at least 5cm in the soil. You can secure your jug in place by tying it to a nearby stake via the handle. Cloches tend to work really well for vegetables like swiss chard, peas, broad beans, and salad leaves.

5. Bring plants inside

Garden containers can crack when the weather takes a dip. You can avoid such issues by wrapping the containers with burlap or bubble wrap. However, when the weather forecasts announce a frost advisory, it’s best to bring your potted greenery indoors to avoid frost-related damage. 

If the temperature reads around -1 degrees Celsius, it may be enough to move your plants to a location such as a garage or a shed – where they can be sheltered even though there’s no heating. Although, anything lower than -1 degrees Celsius will require you to move them to a place with proper insulation to ward off frost injuries. 

6. Water well

Moist soil absorbs and retains heat better than dry soil. The water content in the soil promotes heat better near the surface, which allows the plants to remain warm in cold conditions. That’s why watering your plants and covering them with blankets or cloches will help keep them well-protected when the weather turns cool. 

Woman hands add mulch to plants to protect them from frost

7. Add mulch

Mulching can also be of value for gardeners looking to keep a few robust plants safe from frost. Adding a thick layer of mulch can help insulate them; however, this method isn’t recommended for seedlings or gardeners with a sizable area to look after. 

When the forecasts announce low nighttime temperatures, you can use compost to cover the plants that need extra protection. However, be sure to remove the thick layer of mulch when the weather’s back to normal to avoid damage. 

8. Create protective tents

You have the option of creating a protective tent for your plants with the help of a string, bubble wrap, horticultural fleece and bamboo canes. Start by inserting the bamboo cane(s) into the ground near the plant you want to cover. 

Cover the plant with bubble (super-satisfying-to-pop) wrap or horticulture fleece and tie the whole thing in place with the string. For potted plants, forego the bamboo, and instead, bubble wrap the pot and drape loosely with fleece. Use the string to secure the fleece in place gently. 

Vegetable with white frost

Our how-to-protect-plants guide has reached its end. But, we’re hoping we’ve given you enough information to keep your frost-sensitive plants strong and healthy during the winters. Gardening isn’t generally considered a passive pastime or hobby – and keeping your plants and veggies safe from frost will require effort on your part. Nonetheless, if you keep an ear out for frost warnings in the spring and autumn – you’ll have plenty of time to prepare your garden and plants for the arrival of winter.

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