How to grow a walnut from a walnut? I never asked such a question, as my experience suggests that this is not the best way to get a seedling of the variety that you want to have on your site. I grow three walnut trees. Two varietal, and the third just grew out of a nut. And the nuts that I collect from the last are not at all like the one that was planted. But let's take it in order. To put everything on the shelves, we start from afar.
For the successful cultivation of walnuts in order to obtain fruits, it is necessary to know more deeply the economic and biological features of this crop, especially the cultivation of planting material.
How to grow a walnut, breeding methods
Walnut is propagated by seeds and in a vegetative way (grafting).
Is walnut propagation possible with nuts? With seed propagation, the economically useful traits of the mother plant in the offspring are split, more often for the worse, therefore it cannot serve as the basis for creating varietal plantings. It is used mainly for growing stock seedlings, as well as hybrid material for breeding. This breeding method is especially promising for the northern regions of our country, where walnut seedlings are gradually adapting to new environmental conditions of existence. Some of them can produce viable offspring.
To increase winter hardiness, germinated seeds are recommended to be exposed to low temperatures (method of I.V. Borzanovskaya). According to this technique, sprouted seeds (roots no more than 0.5 cm long) are kept for 12 hours in a refrigerator at a temperature of minus 3 degrees, and the next 12 hours in a warm room at a temperature of 18-20 degrees. The term for hardening seeds is 3-5 days. With such an effect of variable temperatures on the sprouted seeds, walnut seedlings were characterized by better growth, increased winter hardiness, early maturity, and productivity compared to control plants (without hardening of seeds).
The vegetative method of propagation ensures the safety, transmission of varietal traits, properties of the mother plant to offspring.
The grafted planting material of walnuts is in great demand, both from the production side, as well as from amateur gardeners. Buying varietal planting material is not always possible. Therefore, we offer the most enterprising gardeners to master the method of vegetative propagation of walnuts on the basis of summer budding, which will allow them to grow walnut seedlings of the desired number of desired varieties on their plot at no particular cost - both to meet their needs and for implementation.
For propagation, it is necessary to use zoned promising varieties that differ in economically valuable properties. Most of them are quick-growing, winter-hardy enough, relatively disease-resistant, fruitful, with fairly good commercial qualities of the fruits.
Now two methods of vegetative propagation have received the greatest development and application in practice: summer budding and winter vaccination (the latter method is more energy-intensive). With timely, high-quality implementation of all types of work, they give approximately the same yield of standard seedlings (65-70% of the number of grafted plants).
To grow stocks, nuts are sown on a permanent place in the fall or in the early spring (in March) subject to their stratification. The method of sowing is single-row in furrows with a distance between rows of 70-8 cm, between seeds - 10-15 cm. Seeding depth - 6-8 cm. Plant care consists of mulching, loosening the soil, weed destruction, and in case of drought - watering.
The most common method of budding is a rectangular shield with a peephole (half ring). To do this, you need a special double knife with parallel blades located at a distance of 3-3.5 cm.
The best time for budding is during the sap flow of the stock (June - the first half of July) with a sleeping eye.
The success of budding largely depends on the quality of the cuttings. They are harvested from healthy, high-grade, high-yielding young trees. Cuttings should be sufficiently ripe, roundish, straight, at least 30 cm long, with large, well-developed vegetative axillary buds.
The technique of budding with a rectangular shield is simple. On the rootstock, using a double knife at a height of 8-10 cm from the soil surface, make two transverse cuts of the bark without touching the wood, then make two longitudinal cuts, as if connecting them with the transverse ones, and separate the strip of bark.
After that, with the same knife, in the same sequence carry out surgical operations on the scion graft so that the eye is in the middle of the shield. Instead of a stripe of bark removed, a rectangular scion shield is inserted into the stock.
Immediately after applying the scion flap, the budding area is tightly tied with plastic wrap, and the eye and petiole are left open. After 20-25 days after budding, the banding material is removed, the shield with the eye at this time, as a rule, grows well with the stock. In the spring of next year, after swelling of the kidneys, the stock is cut at an angle of 65-70 degrees above the flap without leaving a spike. The shoots that appear on the stock are removed during the growing season. On a good agricultural background, oculants grow rapidly, by the time they are excavated they reach a height of more than 2 meters.
This simple technique will allow you to first grow a walnut from a nut as a stock, and then plant a stalk obtained from a tree with the properties you need.
Walnut Tree - Biological Description
Walnut is a powerful tree up to 8-15 m high with a large spreading crown, trunk diameter of 0.5-1.5 m. With growth in free space, these figures can be higher. The growth and development of walnut trees is determined by the place of their growth, soil properties, subsoil, biological characteristics of the variety, stock, and the state of agricultural technology.
Varieties with restrained growth (height of trees 6-8 m) have been created that develop a small crown. They may well be cultivated in small suburban, personal plots.
If the plantings are thickened, then the walnut forms a rare, highly elevated, and if sparse, a thick, sprawling spherical crown, consisting of a large number of skeletal, semi-skeletal branches of various orders. The young shoots are dark green.
Most zoned, promising varieties of walnut during vegetative propagation begin to bear fruit 5-6 years after planting in the garden, and trees of seed origin from 8-12 years of age. Quick-growing varieties of the type Ideal are able to begin bearing fruit for 2-3 years, and some of its varieties can bear fruit twice during the growing season. With age, expansion of the crown, fruiting increases. Full fruiting occurs on the 10-12th year. Its value depends on the variety, growing conditions, as well as on moisture availability. With the use of higher agricultural technology, walnut yield can be easily increased. He bears fruit to a very old age.
In the south of Russia, in the old Circassian gardens grow seed trees of seed origin, which at the age of 80-100 years or more have a fairly high productivity - 80-120 kg per tree. Low labor costs, means of cultivation, and their value make this culture highly profitable.
Walnut belongs to monoecious dioecious wind-pollinated plants. Male and female flowers are formed on the same plant, but separately. Male (staminate) flowers have the appearance of inflorescences in the form of earrings, which are formed from lateral buds on the growth of the previous year, and female (pistillate) flowers are formed in the apical and lateral buds (in the axils of the leaves) of the shoots of the current year. They are green in color. Sticky two-bladed stigmas are well developed.
In the south of Russia, walnut vegetation begins in the first and second half of April, the most active growth of shoots in length occurs in the first and second decades of May, and by the end of June it will die out. The nut blooms in late April and early May, flowering ends in the second or third decade of May. Early flowering and late flowering varieties are distinguished by flowering dates. It is characterized by the phenomenon of dichogamy, that is, the simultaneous maturation of male and female flowers on the same plant, which prevents self-pollination, but contributes to cross-pollination. Plants in which anthers open before the stigma ripens are called protandric, and if stigmas ripen earlier, they are protogynous. Sometimes homogamous trees are found in which the flowering dates of stamen and pistillate flowers coincide. In the latter case, they begin the fruiting period faster, their pistillate and staminate flowers bloom longer, which provides partial self-pollination, respectively, an increase in yield.
The phenomenon of dichogamy must be taken into account when selecting walnut varieties for joint planting on the plantation, combining them so that the flowering of female flowers of some coincides in time with the flowering of male inflorescences of others.
The fruit is a false drupe (walnut), greatly varying in shape and size. The fruit ripening period is extended - ripening begins in late August and early September, lasting almost until the end of the month. Three groups of trees are distinguished by maturity dates: the first is maturing, the second is maturing, the third is late-ripening.
Walnut vegetation in the North Caucasus very often stops with the onset of frost, which is dated to the end of October - beginning of November. The duration of the growing season is 190-240 days.
The root system is powerful, rod type, penetrates to a depth of more than 8-10 m. It has well-developed lateral branches, which go far beyond the crown projection. The bulk of these roots is located in the upper half-meter layer of soil. Walnut sensitively reacts to the close occurrence of groundwater (less than 1.5 m), underlying a dense clay horizon or rock (less than 0.6-0.8 m), in these cases the core root dies, the surface root system develops. In addition, the lack of drainage in a humid year creates the danger of overmoistening the root horizon, which leads to severe inhibition of the root system, and with prolonged flooding - to its complete death.
An important biological feature of walnut varieties is the type of fruiting. Most have an apical type of bearing. The laying of generative organs in them occurs only in the apical kidney of annual growth. However, there are varieties in which, along with the apical bud, some of the lateral ones are also fruit (apical-lateral type of fruiting). It was established that varieties with the last fruiting type are 1.5 times more productive than those with apical fruiting, which should also be taken into account during plantation plantings, giving preference to the first.
Walnut is a heat-loving, but rather frosty and winter-hardy nut-bearing breed. It successfully grows, bears fruit where the average annual air temperature is plus 8-10 degrees, the growing season lasts 150 days, and the minimum air temperature rarely drops below minus 22-25 degrees. However, a walnut can withstand without significant damage lower temperatures in the winter, when the trees are in a state of deep dormancy. For example, in Moldova, there were cases when he suffered a decrease in temperature to minus 25-27 degrees, in Bulgaria - to minus 30 degrees, and in Ukraine - to minus 40 degrees.
Observations of the winter hardiness of walnuts in the North Caucasus showed that short frosts of minus 27-28 degrees do not cause serious damage to trees of local variety forms - they bear fruit normally. Sharp drops in air temperature after a long thaw, as well as at the end of winter, are much more dangerous for him. In such years, fruiting is absent, but the damaged crown is being restored, which lasts at least two years, after which the tree is able to bear fruit again normally. The degree of damage depends on the characteristics of the variety, stock, plant age, plant density, growth location, state of agricultural technology. On a good agricultural background, trees suffer less from severe frosts. Their winter hardiness increases with sufficient moisture in the soil, dry, cold autumn, and an earlier end of the growing season.
Walnut reacts very sensitively to a cooling in the flowering phase (massive dropping of pistillate flowers occurs already when the air temperature drops to 0-1 degrees Celsius. To avoid this, it is necessary to grow late-flowering varieties that go away from the return of cold weather during flowering, or cultivate it where there are no late spring frosts.
Walnut does not tolerate heat, prolonged soil atmospheric drought, which inhibits the growth of trees, reduces the size, quality of the crop. There are cases when an increase in temperature of more than 37 degrees caused premature shedding of fruits from the bottom of the crown. The negative effects of drought are exacerbated when grown on poor, dry soils. To increase the resistance of the walnut tree to drought, it should be planted on rich deep soils where 550-600 mm of atmospheric precipitation falls during the growing season.
It should be noted that most regions of the North Caucasus have a favorable combination of climatic factors that ensure normal growth and annual fruiting of walnut trees.
Walnut has a high shoot-forming ability, therefore, tolerates crown rejuvenation well. It quickly recovers with severe freezing of the branches in severe winters, when the air temperature drops to a critical mark for its wintering, below minus 28-30 degrees. At the same time, the crown is restored due to the abundant growth, which is formed on the lower parts of the old-aged branches that are not damaged by frost, and if the entire crown has frozen out, then it is due to the growth formed at the base of the tree from the root neck.
Walnut is a photophilous culture; therefore, it grows well and regularly bears fruit when it is thinned out on a plantation where there are conditions for free growth and the development of a powerful spreading crown. With thickened plantings, where the access of sunlight due to lateral shading is limited, the trees are very elongated, they form a crop only in the upper part of the crown.