Today we talk about how to protect plants from frost, a matter of great concern for gardening and horticulture enthusiasts during this time. As we know, intense cold can damage plants, but with some simple precautions, the problem can be solved. Let’s see, therefore, for the different categories of interest, what measures can be taken to save our crops from frost. How to protect organic vegetables, garden plants, potted fruit trees, and those planted directly in the ground?
Naturally, this topic needs to be approached from two perspectives. Firstly, we need to understand which types of plants we want to protect. Secondly, attention must be paid to your geographical location and the climatic zone you are in. For the coastal areas of southern Italy, for example, protecting plants from frost is a relatively minor concern. However, in many other inland regions of the peninsula, defending our plants from the cold is not something to be underestimated.
How to protect vegetables from the cold
Let’s start with simple techniques to protect vegetables from frost during the winter months. In our opinion, the riskiest months are January and February. This is because, in recent years, we have been experiencing rather unusual December temperatures.
All vegetables, in general, suffer from frost. By “frost”, we mean temperatures that drop near or below the freezing point, especially during the night.
Frost usually occurs when the sky is clear, meaning there is no precipitation. Moreover, the humidity levels should be relatively low.
Protecting plants from frost is especially necessary during prolonged cold spells. When frosts occur repeatedly over a long period, plants are at risk of suffering serious damage. However, sporadic frosts, which occur from time to time, usually allow our vegetables to recover well. The plants suffer but can still resume their vegetative activity.
Materials for mulching
The first technique to protect plants from frost is natural mulching. Vegetables like cauliflower, black broccoli, chard, spinach, lettuce, young broad beans, garlic, peas, and savoy cabbage benefit from the application of a layer of mulching material for protection.
This mulching material can be various, ranging from classic straw to dry leaves, bark, or wood chips. These materials are readily available during the autumn season.
With natural mulching, the plants will be protected from the temperature fluctuations during the night. It is almost as if you were applying a blanket that helps the soil to remain warmer. That’s the principle.
If the climate in your geographical area is not excessively harsh, this protection may be sufficient. Otherwise, it is advisable to proceed with further protection against low temperatures, namely: the cold tunnel.
The cold tunnel
Cold frame tunnel
The cold tunnel is like a small artisan greenhouse. This greenhouse serves as excellent protection not only from frost but also from heavy winter precipitation.
This small greenhouse for plants can be homemade, making it quite economical. Its use does not exclude mulching but complements it. With precipitation, in fact, the mulching material can lead to rot, which is never welcome for our vegetable plants.
Here’s how to proceed with the DIY construction of this cold tunnel.
Building the cold tunnel
Using these easily available in stores, you can create a tunnel on which you lay and secure a transparent plastic cover.
The precautions for building a cold tunnel properly are:
- The arches must be well anchored in the ground, at least 15 cm deep, and perfectly perpendicular to the ground
- Then, they must be positioned at the same distance from each other
- The plastic cover must be well stretched, without sags that could cause problems in case of snowfall
- Finally, use anchoring stakes with a U-head or straight type, long enough to secure the cover to the ground
The cold tunnel should be left open at one end. This allows proper ventilation during daylight hours. By doing so, we avoid the problem of condensation, which can cause rot or allow fungal diseases to spread. In the evening, however, the tunnel should be closed to protect the plants from frost.
So remember: close the tunnel at night and keep it open during the day.
This small plant greenhouse can be set up to protect ongoing crops or in the pre-sowing phase. Another precaution to protect plants from frost is to limit irrigation. Watering should be done as needed during the central hours of the day, allowing the soil enough time to dry.
How to protect fruit trees from frost
“How to protect plants from frost?” is not a question with a single answer. As we have already said, it depends on the area and the specific plant. After discussing vegetables, let’s now see how to protect fruit trees from intense cold.
For fruit trees, a distinction must be made between those that are cold-resistant and those that are more delicate and sensitive.
For the first group, there is no need for particular protection. These include apple trees, pear trees, persimmon, pomegranate, cherry, hazelnut, medlar, walnut, chestnut, and small bushes like blackberries, currants, and raspberries.
Among the fruit trees that need protection from prolonged frost are citrus trees, especially the lemon.
Other trees that must be protected from prolonged frost include almond, peach, apricot, and fig trees. In short, typically Mediterranean crops.
For these trees, especially if grown in pots, the easiest and most common protection is using non-woven fabric, also known as TNT.
Non-woven fabric is an effective method to protect our fruits from excessive cold. It is a synthetic material, available in various sizes, with a lightweight and breathable structure that covers the entire plant. It is also known as agricultural fabric, as it allows plants to receive light, air, and rainwater while providing excellent protection from sub-zero temperatures.
For potted fruit trees, the non-woven fabric should be tucked under the pot. For shrubs or trees planted directly in the ground, the fabric should be tied around the trunk.
How to protect succulents from frost
But how do we protect plants from frost when we are dealing with succulents? This category, in general, does not tolerate the cold well (and indeed, they are often found in deserts).
Generally, in domestic gardens, these plants already enjoy some degree of protection. They are usually placed in pots and kept in covered areas, if not inside the house. Of course, in the case of indoor plants, of any type, the issue of protection from frost does not arise. If these plants are positioned in the garden, directly planted in the ground, and happen to be in particularly exposed areas, an excellent protection, in this case, can also be non-woven fabric.
Terrace greenhouse
For potted plants without adequate protection, a solution is to use balcony or terrace greenhouses directly.
Balcony greenhouses are easily available for purchase and can be used in any outdoor space. For those with available space, however, it is worth considering the idea of setting up a larger garden greenhouse.
This way, you’ll have a space to protect plants from frost and, at the same time, create your little corner of paradise.
Further Reading
- ResearchGate – Integration of a Frost Mortality Scheme Into the Demographic Vegetation Model FATES – This article discusses the integration of a frost mortality scheme into a demographic vegetation model.
- ResearchGate – An intelligent radiation frost forecasting and warning system for agricultural environments – This research presents an intelligent radiation frost forecasting and warning system for agricultural environments.
- University of Arizona – “Protecting Ornamental Plants from Frost Damage” – This guide provides a comprehensive overview of the methods to protect ornamental plants from frost, including the use of water, covers, and heaters.
- University of Georgia Extension – “Winter Protection of Ornamental Plants” – This publication discusses the various methods of protecting ornamental plants during winter, including the use of mulches, covers, and windbreaks.
- Iowa State University Extension – “How to Protect Plants from Frost and Freeze” – This comprehensive guide discusses the difference between frost and freeze, and provides tips on how to protect plants during these events, including the use of covers, cold frames, and proper planting times.
- Mississippi State University Extension – “Protecting Plants from Cold Temperatures” – This article provides a detailed guide on how to protect plants from cold temperatures, including the use of covers, heaters, and proper watering techniques.
- Penn State University Extension – “Understanding and Preventing Spring Frost and Freeze Damage to Grapes” – This article focuses on protecting grapevines from frost and freeze damage, including the use of wind machines, heaters, and covers.
