Grapes have always been considered a southern resident, very demanding of warmth.
In the conditions of the short Ural and Siberian summers, it was not a promising agricultural crop. However, in recent decades, breeders have developed new varieties that can withstand severe frosts without damage. These varieties have become very popular among enthusiastic winegrowers in the Urals and Siberia. The Urals are located in two climatic zones: temperate and subarctic. Winter temperatures in the region range from -16 ˚С in the Southern Urals to -24 ˚С in the Arctic region. Summer here is short and can be dry and hot, but can also be rainy and cold. Due to such climate instability, the Urals belong to the zone of risky agriculture. However, if you follow agrotechnical rules, you can get good harvests of sunny berries here too. Read the article: preparing grapes for winter.
The timing of covering grapes for the winter depends on the region where the vineyard is located.
Victor Tatievsky
We all learned from the books of southern authors, but, gradually gaining experience and developing our own technology for northern viticulture, we began to understand that this experience was not suitable for us. It is also better for winegrowers in central Russia to work using our technologies, rather than those from the south. Our technologies are developed “with reserve”: if the winter is harsh, then the measures taken will save the grapes, and if it’s mild, then it’s okay if somewhere we overdo it with protection from frost.
Vitor Tatievsky in his vineyard.
After long discussions of many years of experience, northern winegrowers came to the conclusion that it is better to cover the grapes before frost.
Dubrovsky pink
Victor Tatievsky
It all depends on the technology that the winegrower uses. If it puts a lot of stress on the bush, then the vine ripens early, so you can cover it early - I know a winegrower who covered his bushes until September 15th. I don’t do this myself, but I have to do it before frost. From October 15 to October 20, you can safely close. If you do this later, the vine must be protected from frost, covered with polycarbonate, covering material, or polyethylene.
Features of the climate of Siberia
In Western Siberia the climate is sharply continental, and the weather conditions in the eastern part of Siberia are influenced by the relief features. Winters in the macroregion are long and frosty, and summers are short. But such conditions also have advantages for gardening. The grapes are resistant to pests and are not susceptible to diseases. In Siberian conditions, it is not affected by the dangerous phylloxera aphid.
Despite the climate, early and some mid-season varieties grow successfully and produce a harvest, provided that the vine is covered and protected from freezing.
Timing for covering grape bushes in Siberia
Siberian autumn takes a short period of time, no more than two months, and quickly turns into a harsh, long winter. For this reason, they begin to cover the grapes at the end of September - beginning of October in order to catch them before the first frost. But there's no need to rush.
You can remove the vine from the trellis earlier, but it is better to wait until the leaves fall and do not pick them off yourself. At this time, complex biochemical processes take place in the vine for the complete ripening of shoots and buds.
At what temperature should you cover grapes?
There is no need to wrap the entire bush at once. Temperature changes can cause condensation to form and dampen the plant. A period is needed when the fluctuations in sub-zero temperatures pass - before the snow falls. It is useful to harden the plant at -5...-8°C. Finally, the grapes can be covered at a constant temperature below -10°C.
Reference. In Siberia, the covering of grapes is completed by mid-October.
Why should the vine be protected from frost?
The vine may not be ripe in the fall, and encountering frost will be disastrous for it. In addition, the first frosts can be quite severe, and they can kill the buds of even mature vines.
Electrical tape marks the border between ripened and unripe vines; this will allow you to see which part of the vine will ripen under cover in winter.
Victor Tatievsky
Much depends on the frost resistance of the variety, but the bush gains frost resistance gradually. If the frost resistance of a bush is -30 degrees or more, then in September it is -5 - -6 degrees, in October -7 and below, and so on. Therefore, frosts in the first ten days of October are especially dangerous. And if the variety is not winter-hardy, frost resistance indicators are lower, then the first frost can kill the vine.
Winegrowers usually make shelter for all the bushes at once, without dividing them into frost-resistant and non-frost-resistant. Therefore, it is better to play it safe and cover everything early.
A vine that has not been hit by frost is always preserved better during wintering.
Autumn pruning before shelter
Why is it better to prune grapes in the fall? If this is done in the spring, liquid – “juice” – will flow out of the cuts. It will take time for the bush to recover; the growing season slows down by about two weeks. Accordingly, the harvest will ripen later.
Pruning can begin only after the leaves have completely flown. Even damaged, semi-dry leaves continue to nourish the bush with useful substances. It is advisable to carry out the procedure in dry weather. The correct time for autumn pruning of grapes before sheltering for the winter depends on the region and actual weather; in the Urals and Siberia it could be September, in the Moscow region - October, in the Krasnodar Territory - November.
Not only beginners, but also experienced winegrowers often neglect to handle the pruning shears during pruning. When you need to process a lot of bushes, it’s a pity to waste time wiping. But this is truly dangerous. Different grape varieties have different resistance to infections. An infected vine with high resistance to the disease will not show this outwardly, but will be a source of disease. During pruning, the infection will spread to the rest of the bushes, some of them will not be able to fight, and curing the disease will not be easy.
In order not to waste time wiping the pruning shears, we prepare an alcohol-based disinfectant in advance and pour it into a jar. Having finished pruning one bush, dip the tool in the solution and continue working.
How to cover grapes for the winter
This is how Viktor Tatievsky himself does it
- Spreads polyethylene on the ground.
Victor Tatievsky
Polyethylene becomes a barrier between the vine and parasitic fungi and microorganisms in the soil, which lead to the formation of mold and damping off. While studying the physiology of grapes, I found several more ways to create such a barrier: pouring an even layer of sand, laying roofing felt... Any wrapping of the vine (in a covering material, in a polypropylene bag) will also create such a barrier.
But, according to Viktor Vasilyevich, polyethylene in the design of a winter shelter has an important advantage - it significantly reduces the humidity of the vine. The photos below show the opening of grapes in the spring of 2017. We see that the huge puddles in the shelter did not damage the vine in any way; it is dry and clean.
- Places the vines on polyethylene, tying them into bundles with ropes if necessary. If wrapping is planned, then tying into bundles is necessary.
- Covers the vine from above with covering material and insulation.
Victor Tatievsky
If the winegrower expects that the winter will be cold, frosts will come early, and there will be little snow at this time, it is better to use 4-6 layers of covering material. If other insulation is used: spruce branches, bags with foam chips, sawdust or leaves, then 1-2 layers of covering material will be sufficient.
Our expert has been using No. 60 agril bags with foam chips for several years. For reliability, the agrill is folded in two layers.
Bag dimensions: unfolded: length 2 m, width 0.7 m, thickness 0.1 m (150 liters of foam chips are poured into the bag).
The bag turns out to be very light, it is easy to give it the desired shape, it does not put pressure on the vine, does not cake and does not get wet. The chips can be purchased from a building supply store or from a foam board manufacturer.
- Another layer of covering material is placed on the bags so that they remain clean after wintering, and another layer of polyethylene is placed on top.
Victor Tatievsky
Polyethylene protects the vine from precipitation. And two layers of polyethylene, at the bottom of the shelter and on top, create the effect of a double-glazed window and retain heat well.
Damping off with this design of winter shelter for grapes is excluded.
Victor Tatievsky
All moisture comes from the soil, and if there is polyethylene below, there will be no damping off. But in the spring the top polyethylene will need to be removed.
This is an axiom: if the grapes are covered with an airtight material on top, it must be removed in early spring.
Victor Tatievsky
I remove the polyethylene in early spring and leave only two layers of covering material, adding polyethylene only when necessary.
Is it necessary to spray the vine with vitriol?
Before wintering, grapes are sprayed with iron or copper sulfate to destroy pests that may overwinter on the vine.
Iron sulfate also slows down the growing season: in the south, this technique allows you to avoid spring frosts, but in northern viticulture it has a negative effect.
Copper sulfate does not slow down the growing season, but it is not a fact that there is much benefit from it. There was a big discussion in the Russian grape community about the need for its use, and the participants came to the conclusion that such spraying was most likely not necessary.
Victor Tatievsky
Honestly, I have never sprayed grapes with copper and iron sulfate, neither in spring nor in autumn. But I don’t do anything unless really necessary, “just in case.” Everything is fine with me without spraying, my vineyard is always clean.
But let us repeat - our expert grows grapes in the Altai region, where the crop is infected with diseases and pests much less than in the south and even in Central Russia.
Covering material
All material used for shelter must be disinfected after it is removed from the vineyard in the spring, and stored in a dry place. In the fall you need to get it out and prepare it for use:
- review, reject and destroy damaged boards or straw mats;
- collect and dry fallen leaves, and then treat them with disinfectants;
- Spruce spruce branches will be an excellent covering material - it will protect the vine from mice;
- prepare and dry medicinal plants that will repel pests - tansy, calendula, wormwood and others;
- cover the covering material with these herbs.
Summarizing
As Viktor Tatievsky says, each winegrower develops his own technology, using the materials that are at hand. When you try and experiment, you will definitely find your own, the best way of winter shelter for grapes. But the general direction should remain this way:
- It is better to cover the grapes before frost sets in;
- It is necessary to create a barrier between the vine and microorganisms that live in the soil;
- Having laid the vine on the barrier, you need to pin it to the ground;
- The insulation layer must be sufficient;
- The top of the structure must be covered with polyethylene - this will protect it from precipitation and effectively retain heat.
We invite you to read an article on FORUMHOUSE about how to get a grape harvest a year earlier, as well as chat about grape topics, learn winemaking and watch a video in which Viktor Tatievsky talks in detail about the technologies of northern viticulture.
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