How to Propagate Walnuts? A Detailed Guide to the Latest Propagation Methods

Walnut is a nut that originated in China. The main propagation methods for growing walnuts are seed propagation, grafting propagation, and cutting propagation. Among them, cutting propagation is the fastest and easiest way to achieve survival. In addition, sowing must be done after artificial treatment, otherwise the seed shell is too hard and it is very difficult for the seedlings to emerge. The best method is to propagate rootstock from seed and then take scions for grafting. This method is the most widely used, its genetics are unaffected, and it can also obtain the excellent characteristics of other varieties. Let's take a look at the specific details right away.

I. Sowing Propagation

The collected seeds are sown in spring, or sown in autumn, when the temperature is suitable. March and April in spring are the best sowing periods. The seeds must undergo stratification to promote germination before sowing; direct sowing makes it very difficult to germinate. The stratification site should be a warm place facing the sun, and generally, one layer of sand and one layer of seeds are used, maintaining a temperature of 2°C to 5°C. The humidity should be around 60%. After two months of stratification, they can be taken out and sown. Therefore, stratification must be carried out in advance. Alternatively, before sowing, soak the seeds in cold water, soak and press them, changing the water once a day, and after a week, expose them to the sun until the shells crack, then sow. For hole sowing, place the seeds horizontally, cover with about 6 cm of soil, then water and manage them.

II. Grafting Seedlings

Generally, hickory is used as the rootstock. Wild hickory has strong adaptability, strong resistance, and sturdy stems. Grafting other varieties can bring fruiting earlier. For scions, choose one-year-old healthy branches of medium vigor with no pests or diseases from robust mother plants of excellent varieties. If there are many scions, they can be stored in wet sand. The rootstock is required to have a diameter of about 1.5 cm, and grafting is done at a position about 10 cm above the ground. After cutting, grafting must be done immediately; bleeding affects survival, and the scion can be placed in the mouth to prevent bleeding. The cleft grafting method is generally used. After fixing, check frequently, remove sprouts, and remove the film after survival.

III. Cutting Propagation

Generally, cutting is the fastest method to produce seedlings. Cut one-year-old to 3-year-old branches from the outer part of the mother plant, with a thickness of 1.5 cm. Take branches about 15 cm long, and some pruning is also needed, so that finally a 10 cm branch is used for cutting. Keep three to four leaves on the upper part of the branch, then soak the lower end in an alcohol solution of rooting powder, after that insert it into a moist seedbed, cover with pine needles to keep warm, set up a shade net, and control the temperature between 18°C and 25°C, not exceeding 30°C and not below 10°C. Later maintenance is also needed.

IV. Points to Note

For sowing, note that as long as the shell can be made to crack without damaging the inside of the seed, any method can be used, as long as it promotes germination and breaks through the seed shell. For grafting, better rootstocks or scions can be selected, as long as the plant can simultaneously have better growth characteristics. In the early stage of cutting, there are no roots, so moisture must be maintained to keep the cutting branch vigorous, but not too much, which would cause the lower end to rot and fail to root.

Compared with other fruit trees, walnut propagation is relatively difficult no matter which method is used, so more methods should be used to help propagation. But all three methods have their own advantages, so it depends on your own choice and on time and requirements to decide the growth and propagation method.