The climate in Siberia is very harsh. Winter frosts can cause frostbite in the orchard. For this reason, apple trees need to be prepared for the cold by covering them. Protecting the trunk and root system allows the trees to survive severe frosts with minimal damage. However, using low-quality materials or improper covering techniques can lead to unpleasant consequences.
Do apple trees need to be covered for the winter?
Survival in Siberia is extremely challenging for apple trees, especially in windy winters with little snow. During the coldest months, temperatures can drop to -50°C (-52°F) or lower. Under such conditions, trees can freeze. This is especially true for weakened, young apple trees. The tree's location is also important. If it's located in a lowland or the groundwater table is very high, root freezing can occur when temperatures drop to -15°C (-14°F).
Covering is necessary not only to protect the roots and trunk bark from freezing. It also serves other functions, including:
- protection of bark from rodents and hares;
- shelter from the drying wind;
- protection from the bright spring sun (if How to properly cover an apple tree for the winter, whitewashing is sometimes not necessary).
In Siberia, all apple tree varieties need to be covered. But special attention should be paid to those with low cold tolerance. To ensure these trees survive the winter successfully, cover not only the trunk but also the area around the trunk.
When to insulate apple trees for the winter
The timing of all preparatory work depends on weather conditions. In Siberia, frosts begin as early as December. It's best to cover apple trees 1-2 weeks before the expected cold snap. This can be done in late November if the forecast is favorable. If early frosts arrive, you can insulate the orchard as early as mid-November. Mulching around the trunks and wrapping the trunks with burlap or spunbond is still a good idea, even before frost sets in. However, it's best to insulate young trees in advance.
Preparatory work such as digging around the tree trunks, watering the apple trees, and fertilizing should be done a month before the onset of frost. For Siberia, mid-November is the optimal time. You can complete all this work, whitewash the trunks, and insulate them immediately, or postpone the insulation for 1-2 weeks.
Materials used for shelter
Natural and synthetic materials can be used to insulate the tree trunks and surrounding area. The main requirement is breathability. Wrapping plastic or other airtight materials around the trunk alone is not recommended. The bark underneath can rot, which will negatively impact the tree's health. In some cases, using such coverings can even lead to the death of the apple tree. It's best to use the following materials:
- spunbond;
- newsprint;
- burlap;
- rags;
- agrofibre.
It's best to avoid straw, as mice love to nest in it. Reeds can also attract rodents. Avoid using sharp-edged wire or other devices that can easily damage the bark to secure materials. When using paper or newspaper, wrap the trunks with a protective waterproof layer. Construction materials such as laminate flooring pads and roofing felt are often used to cover young apple trees. These can be wrapped around the trunk to protect the bark from cold and the elements.
Preparing apple trees for winter in Siberia
When preparing your garden for winter, don't forget about soil cultivation. This can be done after the harvest. Tree trunks should be dug up in the fall. This is necessary to improve air circulation. Pests or their larvae are usually present in the soil. Digging mixes the soil, bringing the lower layers to the surface. This kills the pests.
The diameter of the tree's trunk circle expands over time (from 1 m to 2.5 m). The amount of fertilizer is calculated based on the age of the apple trees and the width of the tree's trunk circle. In the fall, phosphorus and potassium fertilizers should be applied at a rate of 60-120 g of superphosphate and 30-60 g of potassium salt. These can be replaced with complex fertilizers. "Osennee" and similar fertilizers are suitable. It is very important that they do not contain nitrogen. Manure, humus, bird droppings, and other organic nitrogen fertilizers should not be added. They stimulate the growth of shoots near the trunk, which is completely unnecessary in the lead-up to winter.
In the fall, it's essential to prune old and diseased apple tree branches and suckers. Water suckers should also be removed. This will help prepare the trees for the onset of frost and preserve them. Sometimes, improperly growing branches can interfere with proper insulation. In this case, they should also be pruned.
Before winter, apple trees must be whitewashed. This is necessary not only to protect against pests and rodents. In spring, the tree bark becomes extremely hot from the bright sun, causing frost cracks to form. Whitewash or paint prevents bark damage. For the same reason, only light-colored, rather than dark, materials should be chosen for tree insulation.
Trees can be whitewashed with lime or a special paint. Experienced gardeners add clay to the lime. This makes the coating more durable and provides additional insulation. Lime should not be used to prepare young or columnar apple trees for winter in the North. This aggressive compound can damage the bark. A special water-based paint or chalk will help keep the trunks healthy. However, chalk is a very unstable coating. Without an insulating protective layer, it will wash off after the first rains.
How to properly cover apple trees
To protect apple trees from frost and rodents, it's important not only to select the right materials but also to use them wisely, following the proper covering technique. Trunk protection should only be applied after all preliminary work has been completed. Trees should be treated with copper sulfate or other fungicides and whitewashed. Pruning should also be completed before insulating.
Burlap, rags, spunbond, or other selected materials are tightly wrapped around the trunks. Apple trees are wrapped to a height of 1-1.5 meters. The material is secured with rope or a thin strip of fabric. The trunks can be additionally wrapped with a moisture-proof material, such as polyethylene or lutrasil. It is important not to wrap the material too tightly around the trunks to prevent the bark underneath from rotting.
Tree trunks should be mulched with sawdust, peat, or spruce branches. Keep in mind that spruce needles and peat acidify the soil. Apple trees grow well only in neutral soils. In the spring, you can test the soil's acidity with pH test paper. If necessary, add slaked lime.
Covering seedlings and young apple trees
In Siberia, it's not recommended to plant apple trees in winter. There's a very high risk of root freeze damage. A fragile plant may not survive the frost. It's best to plant the seedlings in a raised, but wind-protected area, and insulate them well. They can be transplanted to their permanent location in the spring. You can dig a trench about 0.5 m deep in a raised area and plant several seedlings in it. Next, construct a frame and wrap it with the chosen material.
The area around the trunks of seedlings must be insulated with spruce branches or a thick layer of sawdust. The above-ground portions are completely wrapped in insulating material in a bundle, then tied with twine at the top and base. In areas with heavy snow cover, seedlings overwinter under a thick layer of snow.
Young apple trees also require careful winter protection. Their bark is very delicate. These trees are often damaged not only by frost but also by rodents and hares. To protect against all potential dangers, the area around the tree trunks is mulched with spruce branches or sawdust. Tree bark can also be used. The trunks are wrapped in burlap or rags. Insulated materials (foam rubber, synthetic padding) are also acceptable. The insulation is secured around the base of the trunk and at a height of about 1.2 m. Some gardeners construct a frame of twigs. It is convenient to wrap any materials around it. The frame provides excellent protection from wind, precipitation, rodents, and hares.
Foam rubber and other dense building materials are conveniently wrapped around the trunks of young trees and columnar apple trees. Laminate underlayment or even roofing felt can be used. Cut the required amount of material, wrap it around the trunks like a tube, and secure it with twine or special clips.
How to insulate an old apple tree for the winter
Old trees also need to be properly protected. These apple trees don't tolerate severe frosts well. Despite their deep root system, the area around the trunk needs to be mulched. Old apple trees often have cracks and breaks in the bark. These need to be cleaned up before frost sets in. All broken parts should be cut off with a special gardening knife, disinfected first.
In the fall, sanitary pruning of old apple trees is carried out. It's best to postpone rejuvenation until spring. If some large branches were cut in the fall, the cuts should be treated with garden pitch. The trunks of old apple trees are wrapped in burlap, spunbond, or lutrasil, securing them in several places with rope.
Common mistakes when preparing apple trees for winter
To properly cover an apple tree for the winter in Siberia, you need to adhere to the deadlines, select the right materials, and adhere to the correct procedures. Beginning gardeners often make mistakes that can lead to reduced yields the following year or even the death of the trees. The most common mistakes include:
- abundant watering of apple trees before severe frosts (trees need to be watered 2-3 weeks before the expected cold snap);
- using a film that does not allow air to pass through as the main material for insulation;
- using straw to protect tree trunks from frost;
- neglect of mulching the area around the trunk (especially for trees growing in lowlands);
- use of materials that can damage the trunks;
- using lime for whitewashing young trees.
Over-insulation won't do apple trees any good. It's important not to overdo it. If the trees are well-insulated but spring has arrived early, you can remove the burlap or synthetic batting. Failure to do so may cause dormant buds to awaken prematurely.
After removing the insulation, it's worth assessing the trunk's condition. If the tree wasn't whitewashed in the fall, it should be given a coat of whitewash or paint. This can be done when the outside temperature is above 32 degrees Fahrenheit (0 degrees Celsius). Unprotected trunks can become frost-scarred. The bright sun warms the bark, causing sap flow to begin prematurely. Subsequent frosts can cause cracks in the bark. These cracks are easy entry points for pests and fungal pathogens.
Winter protection for apple trees in Siberia is essential. It's best to use high-quality materials that allow the trunks to breathe and don't impede air circulation. Saplings and young apple trees should be covered especially carefully, as they are more susceptible to frost damage.
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