Protecting plants from frost: This is how it works

The first frost is just around the corner and some plants now need protection. Whether with winter protection tents, frost protection fleece or coconut mats - there are many ways to protect the plants.

Frost can damage plants if they are sensitive. Therefore, caution is advised as soon as the weather forecast announces freezing temperatures overnight. Prepare yourself with our tips on how to protect your garden and plants from frost.

Which plants should be protected from frost?

Not every plant needs protection from low temperatures, but frost protection is particularly important for sensitive plants. These include, for example:

• Plants in pots and tubs, balcony plants
• Young plants, both vegetables and young trees
• Frost-sensitive vegetable plants that are to be harvested for a longer period of time
• Greenhouse pre-cultivated plants that you buy in the garden center in the fall or spring
• Tropical houseplants
• Fruit trees in spring, because late frost can damage the flowers
• roses
• Lawn, because some grasses are less hardy than others
• Plants assigned a hardiness zone of 6 or higher

tip: We do not have to protect all plants from frost. Different plants follow different overwintering strategies. More on that in our article “What do plants do in winter?“.

tip: Use the winter hardiness zone of your region and the degree of winter hardiness of the plant as a guide for frost protection. The winter hardiness of ornamental plants and other crops is known and is expressed by specifying the winter hardiness zone. It is a geographic area that encompasses a specific range of climatic conditions that are important for plant growth and survival. Plants that have a hardiness zone of 6 or higher should definitely be protected by us.

At what temperature should plants be covered?

There is no general answer to the question as to the temperatures from which plants should be covered. This can only be clarified in connection with the season and the properties of the plant. Plants that are very hardy may never need frost protection. Others, however, are endangered between autumn and spring or only in spring, frost damage to suffer. Not every plant is equally frost hardy, so always adapt your frost protection to the circumstances.

Tip: Plants that you bought from the garden center in the spring or fall that are actually hardy often fall victim to frost. On the one hand, they have not yet developed a strong root system and are drying up because the cold air draws moisture from the soil. In addition, the plants are not yet used to the environmental conditions outdoors. Due to the warm preculture, they are often particularly sensitive and should also be protected as a precaution.

Protect plants from frost in autumn and winter

In the fall begins the period when you should prepare for antifreeze. Pay attention to the weather forecast and temperatures. The first frosts of the season usually occur on clear, windless nights - then at the latest you should take action.

• Plants can also dry up in winter - make sure to water regularly once the ground has thawed. Avoid waterlogging!
• Evergreen shrubs, roses and heat-loving shrubs must be protected from prolonged frost and winter sun. Only cover the plants with air-permeable materials, such as frost protection fleece or jute.
• Although winter vegetables are not damaged by the cold, you can still cover the vegetables so that you can continue to harvest without problems despite the snow.
• When overwintering pot, balcony and tub plants, it should be noted that most potted plants are harmed by overwintering too warm. Therefore, find out about the respective plant which wintering conditions it needs.
• Cover plants from hardiness zone 6.
• To prevent frost drought, the soil can be mulched and watered on frost-free days. Frost drought leads to a lack of water in plants, because the leaves transpire water, but cannot absorb new water due to the frozen ground and eventually wither. Above all, flat-rooted plants such as rhododendrons are particularly affected. This is because their roots do not reach deep into the soil where plant-available water is found.
• pile up roses.
• The lawn is protected by providing it with a potassium-rich fertilizer in the fall. Potassium increases the resistance of the plants and makes them strong for the cold season. Special autumn fertilizers like ours are suitable for this Plantura Organic Autumn Lawn Fertilizer particularly good with a long-term effect. The nutrients contained must first be decomposed in the soil and made available for the plants. As a result, the grasses are supplied gently and long-term over a period of three months. Perennial plants also benefit from autumn lawn fertilizers, because they can cope better with dry and cold phases.

Protect plants in spring

Plants should be planted in spring up to the ice saints (12. to 15. May) must be protected from frost - because until then there is a risk of night frosts.

• Cover your plants until the icy saints at night, for example with frost protection fleece.
• Tub and potted plants should not be put outside until mid-May. However, they can be placed outside during the day beforehand.
• You can also protect the blossoms of fruit trees from late frosts – antifreeze candles are a good way of doing this.
• Keep a close eye on the daily weather forecast. If temperatures are to drop again after warmer periods, it is important to protect the plants from frost.

Tip: Even if spring plants are sold in the garden center before the ice saints, you should still wait until after this date to plant beds, or plant until then before frost protect.

Winter protection for plants: These options are available

There are various options and materials to choose from that can be used to protect plants from frost. Did you know that snow is also a natural frost protection for plants? It has an insulating effect - just like some of the materials that we are now presenting to you.

Winter protection tents for plants

Winter protection tents are plant tents made of foil in which plants can be stored over the winter. If it gets particularly cold, additional heat can be fed into the tent. Suitable for this is a plant heater, a frost guard or candles. A good place to use winter protection tents are partially hardy potted plants outdoors. However, they can also be used in the spring to pre-culture young plants. The tents come in different sizes, they are translucent and can be reused. The disadvantage is the comparatively high price.

antifreeze fleece

Frost protection fleece for the garden consists of a very light plastic material which is water and air permeable. A thin layer of ice forms under the fleece as a result of evaporation of the soil moisture, which prevents the radiation of soil heat. To avoid plastic, fleece made of 100 percent sheep's wool can also be used. Unfortunately, these come with a disadvantage: They degrade biologically and cannot be used again.
There is also thick construction fleece that insulates better and doesn't tear as quickly as fleece for the garden. However, construction fleece is not translucent and must be uncovered during the day for plants that need light in winter. Fleece can be used in many ways, for example it can be used to protect vegetable crops and young plants. You can also use the fleece to insulate more frost-sensitive trees. Simply wrap the fleece around the trees and tie it in place.

Coconut mats as winter protection

Coconut mats are made from a very durable material that is extracted from the outer shell of the coconut. They can be wrapped around plants or tubs in a similar way to anti-freeze fleece. As a regional alternative, it is recommended to use hemp mats. These are more durable than garden fleece, however they are not translucent and tend to be more expensive than anti-freeze fleece.

Fir branches as winter protection

Twigs from fir or spruce can also be used as winter protection. It is draped around the grafting points of roses by being balled and nested. This insulates the soil and churns wind so it's less cutting and damaging to the delicate parts of the plant. You can also use fir brushwood to cover perennials or tubs. Laid flat on beds, it has primarily decorative value.

Mulch as winter protection

Mulching is recommended in order to also protect the soil and the roots and outlasting organs of plants in it. Materials such as leaves, straw and bark mulch are used to conserve heat and moisture in the soil. In addition, bark mulch, such as ours, protects Plantura organic pine bark against erosion and siltation of the garden soil. In addition, the soil is sustainably supplied with carbon for the formation of humus. The bark of pine trees convinces with its longevity, low heavy metal load and low acid content. For the sake of the environment, our organic pine bark is sustainably produced in the EU.

Jute as winter protection for plants

Jute is a durable natural fiber that is used to make sacks or cloth. It can be used in a similar way to the winter protection fleece. Jute bags can simply be slipped over the crowns of plants or packed in plant pots. However, evergreen plants should not be wrapped up throughout the winter because jute is only slightly translucent. Burlap sacks have long been used as winter protection for roses - in the past, old potato sacks were simply pulled over them. Nowadays jute comes in a wide variety of colors and your garden can become an attractive eye-catcher in winter.

Frost protection film for plants

Frost protection film is a bubble wrap made of clear plastic. The air chambers create an insulating effect. Unfortunately, the plastic does not allow water and air exchange, which means that the plants sprout too early and are more susceptible to frost and diseases. It is therefore better not to drape the film around the plant, but around the planter. Because this must also be protected from freezing in winter. If you want to protect plants directly with the foil, you should only use it for a short time, for example during night frosts in spring, and air it regularly.

antifreeze candles

Frost protection candles are set up in orchards when there is a risk of late frost in spring when flowers are already forming. The time in April is a very critical phase. Put the candles out late in the evening on nights when the temperature drops below 0°C. Around 8 a.m. the coldest weather is usually over. The candles can increase the temperature by up to 3 °C if one or two anti-freeze candles are placed per 20 square meters.

Proper fertilization for frost hardy plants

In summer, plants should no longer be fertilized with an emphasis on nitrogen, but rather with an emphasis on potassium - this makes the plants more resilient and they can survive the winter better. Potassium is stored in the cell sap of the plant and increases the salt content, which lowers the freezing point and increases frost hardness. Avoid high nitrogen doses in autumn. These have a growth-promoting effect, the plant drives out too early and is again more sensitive to frost. In addition, ammonium in nitrogen-rich fertilizers inhibits the uptake of potassium. However, many potash fertilizers contain chloride, to which many garden plants are sensitive.

pile up

In winter, protect perennials and the delicate grafting points of woody plants by piling up a thick layer of soil or mulch. This is an important frost protection measure, especially at the grafting points of roses.

Not all plants should be protected from frost outside. For some it is worth taking them straight to a warmer winter quarters. You can find out what to look out for in our special article on overwintering of plants.