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What frost the leaves of seedlings can withstand in spring. Black currant in the country, tips and tricks for beginners

Our grandparents still remember those times when the climate was stable and quite predictable, winter was snowy and frosty, spring was warm, it was hot in summer and it fell enough precipitation, and in autumn the harvest from the gardens could be harvested until the end of October. Today, unfortunately, weather surprises cause many problems for gardeners and gardeners.

Spring frosts can severely damage fruit trees and shrubs, seedlings of heat-loving crops, flower beds and flower beds. They suffer from the quantity and quality of the harvest, and people who grow vegetables and fruits at a professional level incur significant losses. In order to withstand this natural anomaly, it is necessary to be able to determine the time of the onset of frosty weather and be carefully prepared for this. In this article, we will talk about methods and means of protecting plants from frost, which can come even in late spring.

What are frosts and how to predict them

In order to understand how to deal with it, you need to "know the enemy by sight." Science divides late spring frosts into adventive, radiation and mixed.

Adventure frosts occur during the invasion of the Arctic air masses... There are no methods to resist this natural phenomenon, it is useless to fight them. The good news is that this type of frost is inherent mainly in the northern regions, where the planting season and the timing of bud budding fall on a later period.

Radiation frosts occur quite often, and the reasons for their occurrence have not yet been practically studied. This phenomenon is associated with nighttime cooling of the surface layer of the soil. During the day, the earth heats up under the influence sun rays and gives off thermal energy to the surrounding space. At the same time, equal heat from the atmosphere is coming towards. At some point, this mechanism is disrupted, and the soil gives off more heat than it receives from the air. As a result, there is a sharp drop in the temperature of the surface layer of the earth. Such frosts are of short duration, pass in "stripes" and, as a rule, occur on clear, windless and cloudless nights.

Most often, mixed frosts (adventive-radiation) are observed. They are accompanied by a systematic decrease in temperature during inclement weather, they continue long time and capture large territories.

In order to be fully armed and to be able to provide effective assistance to plants, you need to know about the onset of frost in advance. This information can be obtained from the weather forecast in the media.

As you know, forecasters are often wrong, so you have to rely on your own observations of weather changes, which will help you prepare well for the onset of an unexpected cold snap. The approach of frost is always indicated by a sharp drop in temperature in the evening after a warm spring day and the absence of dew on the grass, as well as calm, dry, cloudless weather.

A bit of theory

Different cultures have different attitudes towards lowering temperatures. Cold-resistant plants adequately resist spring frosts, and when cold weather comes, you should not be afraid for them. For example, carrot seedlings and cabbage seedlings can withstand frost down to -6 ° C, parsnips and celery - up to minus 5, and parsley and lettuce - up to 9 degrees of frost.

Thermophilic crops such as peppers, tomatoes and eggplants cannot tolerate even slight drops in temperature. Hypothermia greatly weakens the plant's immunity, which in the future can cause a number of dangerous diseases.

It should be noted that unhardened and poorly rooted seedlings of thermophilic crops suffer most from spring frosts. Seedlings of early vegetables must be grown in pots. This contributes to the fact that during transplantation it is not damaged root system... Plants take root faster and gain strength, and, therefore, more actively resist cold weather.

Fertile, rich, loose soils help plants in difficult times. They have enough air for active development, they warm up better in the sun. However, loose soil, cleared of weeds, cools down much faster. This must also be taken into account when frost occurs.

Crops planted in unfavorable areas - lowlands and northern slopes - suffer most from low temperatures. Here subzero temperatures are observed more often, and frosts last much longer than in areas with a convex relief or in open areas. Near rivers or large bodies of water, the risk of spring frosts is reduced many times.

Smoke

Fumigation or fuming is a well-known, long-established method of combating spring frosts. This technology is based on the fact that smoke creates an artificial cloud, and the radiation of heat from the soil is noticeably reduced. In addition, when fumigated, dust particles are capable of condensing water vapor in the air, resulting in a fog that protects plants.

To carry out protection against frost by means of smoke on the territory of the site, heaps of materials that are capable of smoldering with weak combustion are prepared in advance. From the bottom of the heap they put firewood and brushwood, on which straw, manure, foliage are piled. All this is compacted and covered with a layer of earth, 2-3 centimeters thick. These smoke heaps (1 meter high and 1.5 meters wide) are designed for a 15 hour fumigation period, for best result it is necessary to lay them out with a frequency of one pile per 10 square meters... For smoke and air to escape, holes are made from above and from the leeward side.

The main disadvantage of this method is its labor intensity. Frosts, in most cases, are not limited to one night, and therefore next night smoke heaps need to be restored. This method is effective only in calm weather and at temperatures up to minus 4 degrees. When the threat of frost is over, the unburned material from the smoke piles can be used as fertilizer or mulch.

Sprinkling and watering

To reduce the thermal radiation of the soil, you can use the method of creating artificial fog (sprinkling). This method is quite effective for short-term frosts. The essence of this method is to spray the plants with water in any way possible. This work can be done at night, right up to sunrise. At this time, the leaves and stems of plants are covered with a thin crust of ice, which is able to protect the culture from frost down to minus 5 °.

Such a method of protection against spring frosts, like irrigation, has long been used in agricultural practice. Watering very well increases the thermal conductivity and heat capacity of the earth. On wet soil at night it is much more efficient than on dry soil; heat is transferred from the depths to the surface. After evening watering, condensation occurs, accompanied by the release of heat. And in this warm cloud, plants will be able to withstand short-term drops in temperature up to -4 degrees.

When using sprinkling and irrigation, the well-known laws of physics apply, when when one gram of water freezes, 80 calories of heat are released, which increases the temperature around the plant.

Sheltering

Covering plants is by far the most effective and most widespread method of protecting heat-loving plants from spring frosts. This method has only one drawback - it is not suitable for protecting large trees.

Individual hideouts are the most primitive part of this method. Such shelters can be built over each individual hole or seedling bush. Any materials on hand will do. You can cover plants with paper bags made from juice or dairy products, or plastic bottles. Covering them with glass jars can be a good protection for newly planted seedlings, and some gardeners use cardboard boxes for packaging for this purpose. To protect crops from frost, burlap and matting are also suitable; many people use hay or sawdust for these purposes.

Tomatoes and potatoes can be covered with soil. At the same time, tomato seedlings are carefully bent to the ground and sprinkled with an earthen layer 2-3 cm thick. Tomatoes can be under such a shelter for several days. Young sprouts of potatoes for protection from frost can be simply spud "headlong".

The use of plastic wrap is possible with some restrictions. The fact is that polyethylene cannot be simply thrown over plants. On frosty nights, when the film comes into contact with leaves, plants can get significant burns. Polyethylene film is not able to retain heat at the proper level and shelters from it can be used only as an additional tool, and only if it is stretched over the frame. You can, for example, cover the plants with paper or hay, and put a frame with stretched polyethylene on top. In this case, an additional air cushion is created, which improves protection against freezing temperatures.

Today, the farm goods market offers gardeners big choice agrofibers. This non-woven polypropylene material is very lightweight, and at the same time has good thermal protection properties. Agrofibre can be applied to plants without using a frame. This material is well permeable to water, and after rain the soil under it does not need to be watered. Moreover, in hot weather, the soil covered with agrofibre perfectly retains moisture.

Agrofibre is available in various thicknesses and densities. Most thin version will help protect plants in case the temperature drops to minus 3 °, and agrofibre of higher density and thickness helps with frosts down to minus 7-9 degrees. When purchasing agrofibre in a specialized store, you should definitely consult with the seller about this. Light agrofibre can be laid directly on the plants freely and without tension, sprinkling with earth along the edges. For large plants, it is better to make wire arches.

Garden protection features

In the event of late spring frosts, the level of danger for trees and shrubs depends on the phase of plant development. For example, buds and already blossoming flowers can be damaged if the temperature drops to minus 3-4 degrees, and the resulting ovaries will die already at minus 1 ° C.

Trees and shrubs growing in the lowlands and on the northern slopes are especially affected, since the intensity and duration of frosts in these places is much higher than in elevated areas and on a flat surface. But near rivers, ponds and other large bodies of water, garden trees and shrubs are almost never damaged by frost. These factors must be taken into account when setting up a garden.

You can protect trees and shrubs in all the ways that we talked about above. That is, smoke, and sprinkling and shelter of plants are suitable here. When a cold snap sets in, many gardeners install many containers of water under the trees. In specialized stores, you can buy smoke bombs, the use of which helps to protect trees at temperatures up to minus 4 degrees. The smoke from such checkers covers the leaves with a layer of paraffin, which protects them from the icy dew that falls in the morning. It is good to cover small trees and shrubs with dense agrofibre using a frame made of wire arcs. However, this method will not work for large branched trees.

Some gardeners, with the onset of spring frosts, heat the garden with special heating pads. For the manufacture of such devices, old iron buckets, large cans of cans and other metal containers are suitable. These containers are filled with used oil, diesel fuel, fuel oil - that is, that combustible material that will not be too expensive for you. A crosspiece made of tin or a chain-link mesh is placed on the heating pad, and a wick in the form of a stick dipped in kerosene is installed on it. When frosty weather sets in, you just need to light the wick. Placing such heating pads at the rate of two pieces per hundred square meters will help to raise the air temperature around trees and shrubs by 5-6 degrees.

Some gardeners, especially those living closer to the northern latitudes, use the so-called biological method of combating spring frosts. The essence of this method is to restrain the beginning of flowering of trees and shrubs.

You can slow down the onset of flowering with early spring watering, which lowers the air temperature in the garden and increases its humidity. Summer pruning of stone fruit crops such as peach and apricot promotes a second growth wave of young shoots, on which later buds appear, and, accordingly, later flowering and fruit formation begins.

A few words about resuscitation

Do not despair if, despite the use of protective methods, your plants still suffer from frost. Many plants can be bounced back by spraying them in the morning before sunrise with water from a spray bottle. This will help them recover faster.

A speedy recovery is helped by root dressing with a solution of nitroammofoska - at the rate of 50 grams per bucket of water (a bucket of solution per 1 m 2). Foliar dressing, that is, spraying the leaves, can also significantly improve the well-being of the crop. For spraying, you can prepare a solution according to this recipe: take 2 grams of boron, copper and manganese each and dissolve it all in a bucket of water. It is best to use fermented weed infusion, if available, instead of water.

Loosening of the soil promotes better regrowth of frozen plants.

And yet, do not rush to remove damaged tomato seedlings - on the side shoots, a quite "tolerable" crop can form.

A person does not have the ability to influence the change in the weather, but we can help our garden and vegetable garden to actively resist the onset of cold weather. To do this, in the spring, you need to carefully monitor changes in weather conditions and prepare all available protective equipment in advance.

Olga Turischeva, rmnt.ru

Our grandparents still remember those times when the climate was stable and predictable enough, the winter was snowy and frosty, the spring was warm, the summer was hot and there was enough rainfall, and in the fall the crops could be harvested from the gardens until the end of October. Today, unfortunately, weather surprises cause many problems for gardeners and gardeners.

What are frosts and how to predict them

In order to understand how to deal with it, you need to "know the enemy by sight." Science divides late spring frosts into adventive, radiation and mixed.

Adventive frosts occur during the invasion of the Arctic air masses. There are no methods to resist this natural phenomenon, it is useless to fight them. The good news is that this type of frost is inherent mainly in the northern regions, where the planting season and the timing of bud budding fall on a later period.

Radiation frosts occur quite often, and the reasons for their occurrence have not yet been practically studied. This phenomenon is associated with nighttime cooling of the surface layer of the soil. During the day, the earth heats up under the influence of sunlight and gives off thermal energy to the surrounding space. At the same time, equal heat from the atmosphere is coming towards. At some point, this mechanism is disrupted, and the soil gives off more heat than it receives from the air. As a result, there is a sharp drop in the temperature of the surface layer of the earth. Such frosts are of short duration, pass in "stripes" and, as a rule, occur on clear, windless and cloudless nights.

Most often, mixed frosts (adventive-radiation) are observed. They are accompanied by a systematic decrease in temperature during inclement weather, last for quite a long time and cover large areas.

A bit of theory

It should be noted that unhardened and poorly rooted seedlings of thermophilic crops suffer most from spring frosts. Seedlings of early vegetables must be grown in pots. This ensures that the root system is not damaged during transplantation. Plants take root faster and gain strength, and, therefore, more actively resist cold weather.

Smoke

To carry out protection against frost by means of smoke on the territory of the site, heaps of materials that are capable of smoldering with weak combustion are prepared in advance. From the bottom of the heap they put firewood and brushwood, on which straw, manure, foliage are piled. All this is compacted and covered with a layer of earth, 2-3 centimeters thick. These smoke piles (1 meter high and 1.5 meters wide) are designed for a 15 hour fumigation period, for best results, they should be laid out at a frequency of one pile per 10 square meters. For smoke and air to escape, holes are made from above and from the leeward side.

The main disadvantage of this method is its labor intensity. Frosts, in most cases, are not limited to one night, and therefore the smoke heaps need to be restored the next night. This method is effective only in calm weather and at temperatures up to minus 4 degrees. When the threat of frost is over, the unburned material from the smoke piles can be used as fertilizer or mulch.

Sprinkling and watering

When using sprinkling and irrigation, the well-known laws of physics apply, when when one gram of water freezes, 80 calories of heat are released, which increases the temperature around the plant.

Sheltering

Today, the farm products market offers gardeners a large selection of agrofibers. This non-woven polypropylene material is very lightweight, and at the same time has good thermal protection properties. Agrofibre can be applied to plants without using a frame. This material is well permeable to water, and after rain the soil under it does not need to be watered. Moreover, in hot weather, the soil covered with agrofibre perfectly retains moisture.

Agrofibre is available in various thicknesses and densities. The thinnest option will help protect the plants in case the temperature drops to minus 3 °, and agrofibre of higher density and thickness helps with frosts down to minus 7-9 degrees. When purchasing agrofibre in a specialized store, you should definitely consult with the seller about this. Light agrofibre can be laid directly on the plants freely and without tension, sprinkling with earth along the edges. For large plants, it is better to make wire arches.

Garden protection features

A few words about resuscitation

Loosening of the soil promotes better regrowth of frozen plants.

And yet, do not rush to remove damaged tomato seedlings - on the side shoots, a quite "tolerable" crop can form.

Olga Turischeva, rmnt.ru

Spring (they are also called return) frosts can cause irreparable damage to fruit crops, even more than prolonged winter frosts... While the plants are dormant, they are able to cope with prolonged low temperatures, but young shoots, leaves, buds, flowers, ovary die from sudden spring frosts.

The sensitivity of plants to sharp drops in temperature directly depends on the stage of bud opening - the more the buds develop, the stronger the damage will be. For example, a blossoming bud dies about - 3.5 o C, for buds, it will be -3 o C, a blossoming flower cannot stand already - 2 o C, at the stage of flowering completion, when the petals are already falling off, -1.5 o C, the ovary dies at -1 o C.

Flowers damaged by frost turn black in the middle, from which fruits will no longer develop. Rusty spots and thickenings appear on fruits damaged by spring frosts. If the ovary touched by frost has not died, then the fruits that have developed from it are deformed, have a non-marketable appearance, although they are quite edible.

Raspberries and blackberries practically do not suffer from spring frosts, since they bloom relatively late. But such fruit trees and shrubs as black currants, gooseberries, red currants, cherries, apples, pears, plums, apricots are extremely sensitive to spring frosts.

Image source https://utahpests.usu.edu, http://ucanr.edu/blogs, https://ask.extension.org, https://www.flickr.com - JohnPaul Stainton

Often the crops in the gardens are ruined spring frosts, which are also one of the reasons for the onset of the frequency of fruiting. How fight against spring frosts and winter frosts... To avoid these negative phenomena, it is necessary for places that are often exposed to the destructive effects of spring frosts, to select late-flowering breeds and varieties. An effective means of combating frost is also smoke screens... A good smoke screen increases the air temperature in the garden by 1-1.5 °, which is decisive for short-term freezing. Fogging in the garden should be prepared well in advance. The probability of freezing can be determined using the Brownov graph. In cloudy weather, the chance of frost decreases. The harmful effect of spring frosts reduces abundant watering of the garden before flowering.
Various combustible materials are used to smoke the garden: leaves, straw, manure, garbage. You can burn crude oil or waste oils in buckets or metal cans. For more smoke generation, fine coal dust is added to the burning oil. The smoke of the garden begins when the temperature drops to 2 ° C and, if there is a frost, it continues for 1-2 hours after sunrise.

Impact of spring frost on apricot harvest

Apricot harvest often dies not from early spring frosts, but rather from thaws in winter when the temperature rises to 15-18 ° C above zero. The buds are extremely early maturing. Already after 15-20 days after the leaves fall, in the presence of heat and moisture, they are capable of flowering.

As established, fruit buds bloom in everyone not when the soil thaws and the beginning of the active life of the roots, but from warming air... Therefore, by freezing the soil by throwing snow under the trees and covering it with straw, as previously recommended in the literature, it is not possible to protect apricot buds from swelling and death during winter thaws. An effective means of delaying early bookmarking and the formation of flower buds in apricots, as practice has shown, is strong pruning, which enhances vegetative growth, delays the formation of fruit buds. Not being fully formed by the beginning of winter, they can more easily tolerate warming and sudden temperature fluctuations than a significant part of them remain in the spring.

Increasing frost resistance of fruit trees

Trees grafted on paradise, and - on, and unvaccinated quince trees often suffer from frost damage to the root system during snowless winters. To increase frost resistance fruit trees carry out water-charging watering of the garden in the fall, after the leaves have fallen, which improves the conditions for overwintering dwarf trees and quince. If it is not possible to water the garden, then the trees are covered with a layer of straw or manure.

varieties Renet Simirenko, Renet champagne, Renet Landsberg are especially sensitive. In places where there is a large amount of moisture, a relatively cool summer lasts, and winter comes 2-3 weeks earlier than in the steppe regions, these apple varieties and a number of pear varieties are almost annually did not finish the growing season by the beginning of winter... In winter, fruit buds and one-year growth froze in the trees.

To combat this phenomenon for three years phosphorus and potash fertilizers were applied... And this measure helped: the winter hardiness of trees has sharply increased, freezing of shoots is almost not observed, the trees began to shed their leaves in a timely manner. Increasing frost resistance of trees by the introduction of phosphorus and potash fertilizers can be successfully applied in

The threat of spring frosts, or "matinees", does not disappear even with the onset of warm days. Return frosts can not only reduce yields, but also completely destroy fruit trees.

Despite the seemingly stable warmth, garden plantings are often injured by frost. Positive daytime temperatures can unexpectedly change to negative values in the evening or at night, not only in the surface air layers, but also affect the top of the soil.

Spring frosts

The peculiarity of spring frosts is their localization. Depending on the mechanism of the process, the following types of frost are distinguished:

Radiation frost

Such processes are typical for the night time. They usually occur during the passage of an anticyclone, when the soil is cooled as a result of effective radiation.

Advective frosts

They are the result of advection of air masses and are observed with the arrival of colder than earth surface, air. Such frosts are typical for the second half of May and arise from the invasion of the Arctic air.

The most dangerous for garden plantings are combined frosts, which combine the features of radiation manifestations and advection processes.

Combs high blood pressure and anticyclones create low air humidity, calmness and lack of cloudiness, which favors the formation of frosts. In lowlands, cold air tends to linger, and the frequency of frosts increases.

Effects of frost on trees

In the central regions of Russia, "return" frosts are often observed in late May, and sometimes in early June. Even despite a slight decrease in the temperature background, lasting more than four hours, frosts always pose a very serious threat to garden trees and shrubs.

Usually, the earlier the warm weather sets in, the higher the likelihood of late frosts becomes. The most dangerous are frosts, when the daytime temperature has already established itself at the level of 5-10 ° C. On most fruit plants, already at a temperature of -2 ° C, the flowers receive almost irreversible damage, and the fruit ovaries can die already at -1 ° C. Heat-loving garden trees during frosts with critical temperatures are irreparably damaged and die.

If, after damage from frost, the flowers and ovaries did not crumble, then in the future they will form deformed and low-quality fruits, and the yield will be significantly reduced. Frost damage to flowers in the bud phase of already blossoming flowers and fruit ovaries depends on the location of the garden and the vegetation characteristics of the trees.

Cherry, plum and pear orchards receive the maximum damage from frost. Apple trees bloom a few days later and suffer much less from the effects of spring frosts. Placing garden plantings near any large water bodies and on relief elevations reduces the harmful effects of negative temperatures on fruit trees. To reduce the negative impact of frost, several methods have been developed to minimize plant death and reduce yields.

Protection methods

The following protection of garden plantings from spring frosts has shown the greatest efficiency.

Creation of a dense smoke screen over the garden to reduce the effective radiation of the earth's surface.

Almost any dry garden garbage is well suited for making a frost smoke screen: foliage, manure, tops, straw. It is necessary to determine the leeward side in advance and spread the piles of debris at a distance of three or four meters from each other. When burning, there should be no open flame, the main task is to create smoke that should envelop the trees. Smoke begins without waiting for strong spring frosts, and when the temperature drops to zero and when a further cooling is predicted.

Covering plantings with a special film cover or creating a straw canopy over undersized trees and young seedlings.
For low-growing berry bushes, a good result is given by the use of irrigation, which does not allow temperature indicators to fall below -2 ... -3 ° C.

Not only trunks and crowns of trees are subject to irrigation, but also the entire soil surface around the plantations. A good result is given by filling with water in advance prepared wide furrows or special irrigation rings. When spraying trees, you can use water with a slight addition of chalk. Sprinkling should be carried out until the temperature rises. Premature termination of such activities causes death of flowers and leaves.

The use of special heating pads significantly increases the temperature regime of the lower air layers.

Treatment of trees affected by frost

Spring temperature drops have a very negative effect on fruit trees. In addition to damaging flowers and buds, they pose a threat to the trunk of the tree and are capable of tearing the delicate tissues of the "awakening" cambium. Prevention of such manifestations can be the formation of a low crown of trees and the planting of low-standard varieties.

Low temperatures cause contraction of the outer trunk layers of the tree and increase the pressure on them of the inner tissues. As a result of such processes, breaks and cracks appear. Tree trunks affected by frost must be treated and treated. For the treatment of wood wounds, a garden pitch is used, which promotes the fusion of the crack and restores the integrity of the damaged layers.

Numerous studies show the effectiveness of using the method of spraying some fruit trees with special compounds. It is recommended to spray apple, pear, apricot and peach trees with water with the potassium salt of naphthyl acetic acid immediately after the end of growth, as well as before laying fruit buds. Such treatment with a 0.25-0.05% solution reduces the harmful effects of sudden temperature changes on fruit trees and shrubs.

An experimental method proved the effectiveness of feeding fruit trees with a 5% urea solution immediately before leaf fall, as well as the use of summer pruning of apricot trees according to the Shita method.

Spring frosts in the garden (video)

Some experienced gardeners deliberately delay the flowering of fruit trees by treating the tree crown with a lime solution. Such protection should be carried out not only in autumn, but also in early spring.