The combination of two parts of plants in such a way that they continue to grow successfully together and give tangible progress in development and fruiting is called grafting. It allows you to quickly grow seedlings and collect a richer harvest. Often, gardeners plant seedlings with the onset of a positive temperature, that is, in the spring. However, recently numerous studies and experiments show that winter grafting of apple trees and fruit crops gives high positive results, it is currently more technological and promising.
Prepare
In winter, seedlings are grafted from early January to early spring, but no later than two to three weeks before planting. Choosing a suitable rootstock is a paramount and important task, since not all of them can provide fruits of the desired quality. Harvesting of scion and stock is carried out in autumn. They are stored in a cool basement in wet sand. It is not recommended to store them buried in snow, since the weather is not very stable in winter – frequent thaws are replaced by a sharp cold snap, which can cause the death of buds and wood or freezing of the roots of the stock.
Before the soil freezes, they dig out the required number of first-class two-year-old rootstocks with a developed root system. In this case, the diameter of the root collar bole should be at least 8 mm. The aerial part of the rootstock is shortened to 25-35 cm. If there is no suitable stock, root trimmings can be used, the length of which should be at least 20 cm and the thickness 1-2 cm.
The prepared material is tied into bundles, the upper end is marked at the root segments, this will avoid mistakes during grafting.
Scion cuttings are also harvested in the autumn, before the onset of cold weather. A few weeks before the vaccination, it is advisable to transfer the rootstocks to a room with a temperature of 15-17 C and re-layer with wet moss, sand or sawdust. After that, thoroughly wash the root system, discard frostbitten and diseased cuttings. Place selected healthy cuttings in water for a day.
Grafts are brought into a warm room a day or two before inoculation and also kept in water. Before grafting, sorted cuttings are placed on a work surface and covered with a damp cloth.
Vaccination technique
There are several ways to vaccinate: single or double, copulation, according to the method of Khudyakov, in the butt with a tongue or with a saddle-type ledge. In practice, a method is chosen based on the quality of the stock material and the direction of work.
In general, there are two main methods in plant grafting technology – copulation and budding. The first is grafting with a cutting that already has two or more buds, the second is grafting with a part of the bark that contains only one bud.
The grafting technology includes a relatively simple, but time-consuming chain of operations: selection of a rootstock-graft combination, preparation of rootstocks, direct grafting, and growing seedlings.
Where to start?
In the intended place, an oblique even cut is made using a copulation knife, about 2-3 cm long. At a distance of about 1/3 from the upper end of the cut, a cut is made deep into the wood for the entire width of the grafting knife, so an oblique cut with a tongue will appear on the rootstock.
A similar cut is made on the lower part of the scion branch, the only difference is that the cut is made, retreating a third from the lower edge of the oblique cut. After that, 2-5 buds are counted from the lower end on the branch and a slightly beveled cut is made above the upper one. Then the components are connected, making sure that the tongue on the handle enters the gap on the cut of the stock. It is desirable that the cuts on the rootstock and the cuttings are the same, then the cambium layers coincide. In the case when the thickness of the rootstock is somewhat greater than the thickness of the cutting, the grafted components are combined on one side, and the other side is cut off along the border of the cutting.
The junction of the components is tied with a tape of a dense polyethylene film from the bottom up and tied very tightly. After that, the upper cut of the cutting must be covered with a thin layer of garden pitch. The roots of the stock are cut to 18-20 cm so that they do not bend when planting. Then, for a few seconds, the grafting cuttings are lowered into a container with paraffin heated to 62-65 C, making sure that the grafting site itself does not get into the paraffin.
Storage
Next, the grafted plant is placed in a box horizontally, the walls and bottom of which must be lined with plastic film with small cuts, and sprinkled with sawdust steamed and treated with potassium permanganate. It is advisable to move the box to a warmer room. Often, the splicing of components lasts about 12-14 days for pome crops and 8-9 days for stone fruits. A good adhesion at the splicing site indicates the end of this process.
Already grafted seedlings are stored at a fairly low temperature in a basement or snowdrift until direct planting in open ground. They are planted with the onset of a stable warm temperature.
They are buried during planting to a place tied with a film, and spud up to the level of the upper bud of the scion. Water abundantly, and the young shoots are immediately pruned. You can get acquainted with the technological process of winter grafting cuttings in the video below.
From the buds of the scion, young shoots soon begin to grow. When they reach about 10-15 cm, they leave the dominant one, and carefully remove the rest. Not less than 2 months after planting, you can remove the strapping from the vaccination site.
One-year-olds grown from rootstocks grafted in winter in most areas of the country grow much weaker than the same seedlings after spring budding. Therefore, it makes sense to leave such seedlings for growing for another year. High positive results are obtained by planting in greenhouses from a dense film according to the scheme of 45 x 15 cm, a few weeks earlier than usual. Under such conditions, the growth rate of plants increases by 2-2,5 times.
However, in cases where it is not possible to use greenhouses, it is possible to grow seedlings of fruit crops on the windowsill in a city apartment. After treatment with hot paraffin, the plants are planted in bags of dense polyethylene measuring 18 x 35 cm, in the bottom of which holes for ventilation are necessarily made.
In order to provide a vascular connection between the rootstock and scion as soon as possible, the plants must be kept in a warm and constantly moist soil, preventing it from drying out. This process of fusion of the root and the cutting is called stratification. It can be achieved by maintaining optimal conditions for the occurrence of root pressure, which is necessary for the formation of callus and its speedy transformation into vascular tissue. The chances of survival will be maximized if the root pressure of the graft is sufficient, there is a constant water film on the graft and there is no premature bud germination.
Winter vaccination makes it possible to evenly distribute the load over the seasons. In addition, it can be carried out throughout the winter period in comfortable conditions for the gardener – at the table and in the warmth, which is the best option for people with a sore back. In addition, its process is mechanized. A clear advantage of winter grafting is the possibility of producing seedlings with a closed root system, and they have clear advantages in comparison with seedlings with bare roots. And also an important factor is that this technology can significantly speed up the process of obtaining commercial seedlings, on average by 1,5-2,5 years. Step-by-step instructions for winter vaccination are covered in the attached video.
Video “Winter grafting of an apple tree”
The video will tell about the techniques and principles of effective grafting of fruit crops (stone fruit)