Although there are several species of walnut trees, especially black and white (or fruit) walnuts, the basic instructions for planting and caring for them are basically the same. Yet, due to the existence of hundreds of varieties that have adapted to different climates and have different resistance to diseases, it is preferable to plant walnuts of a native variety. Walnut trees can produce tasty and long-lasting fruit, as well as valuable wood, however novice gardeners should know that they often kill nearby plants! You can plant walnuts directly from fruits, which you can easily find and harvest under trees, but which are rather tedious to prepare, or from seedlings, which you usually have to buy, but which usually have a better chance of success.
Steps
Part 1 of 3: Preparing the Nuts for Planting
Step 1. Be aware of the effort this work takes and the risks to your garden
Preparing walnut seeds for planting can take months to wait and the success rate is low. If you prefer, you can choose to buy a plant, in this case go to the last section. Before doing either method, you need to know that walnut trees, especially the black walnut variety, release chemicals into the soil that can kill many nearby plants, such as pines, apple trees, tomatoes and others.. This aspect, in addition to their considerable size and, sometimes, the aggressive spread of new plants that arise spontaneously, can make them unpopular in the city and in the neighborhoods.
Step 2. Collect the nuts that have fallen from the trees
In the fall, you can pick up some fruits that have fallen from the trees, or you can gently poke the branches with a PVC hose to drop the ripe nuts. Even when ripe and grounded, most nuts are still encased in a thick green or brown skin (husk) that wraps around the shell.
Attention: the husk can stain clothing and irritate the skin. You should put on waterproof gloves to pick them up.
Step 3. Alternatively, you can buy walnuts
If you are considering starting an orchard for the purpose of harvesting nuts or wood, ask a botanist or forest rangers, or do an online search for the species and varieties best suited to your climate and environment.. The best thing is to buy walnut seeds from the trees within a 160km radius of where you plan to plant them, as they are certainly better suited to the climatic conditions of the place. Walnuts generally grow well in areas where minimum temperatures range from -30 ° C to -1 ° C, but some varieties are more resistant to cold than others.
- Black walnut is very expensive and is considered a valuable wood, while white walnut (also called Persian walnut) is grown for both fruit and timber. There are many varieties of each, as well as other less common species.
- The nuts you find in stores hardly contain the moisture needed to germinate. Even if they do, they are likely to come from a hybrid tree or variety best suited to a different climate and you won't be able to successfully grow them in your area.
Step 4. Remove the husk (optional)
Walnuts can also grow without the need to remove the husk, but many people eliminate it to ensure that the internal fruits are intact and to facilitate cultivation. To remove the husk, immerse the walnuts in a bucket of water until the pulpy layer becomes soft to the touch; you can also wait up to three days for the toughest nuts. Break and remove the softened husk with your hands.
- If you let the husk dry, it can become almost impossible to remove it. Try to drive over it.
- If you have to prepare a large amount of nuts, run them through a corn grinder or spin them in a concrete mixer with gravel and water for 30 minutes.
Step 5. Keep the walnuts moist during the winter for 90-120 days
Nuts, like many other seeds, need to be in a cold, humid environment before the plant awakens from its dormant phase and sprouts from the shell. It can take up to 3-4 months, depending on the variety, during which the fruits must be kept moist. This process is called "layering" and for walnuts it can be done in one of the following ways:
- If you have a small amount of walnuts, put them in moistened peat moss or in damp sand, inside plastic bags and stored in the refrigerator or in another place between 2-5 ºC.
- If you have a large amount of walnuts, dig a hole in soil with good drainage, 30 to 60 cm deep. Fill the hole by alternating individual layers of walnuts with 5cm layers of sand, leaves or mulch. Cover the hole with a net to keep rodents away.
Part 2 of 3: Plant the Nuts
Step 1. Stop the cold layering process one week before the expected germination, but keep the seeds moist
When the soil has thawed and at least 90 days have passed, you can remove the seeds from their cold environment. You should notice a small curl emerging. Still keep them in a humid environment for a week before planting them.
Step 2. Choose a suitable spot to plant them
All walnut species require good quality soil, this is even more important if you are planning to start an orchard. Choose a location with well-draining clay soil that is at least 90 cm deep. Avoid steep slopes, hilltops or rocky and too rich in clay soils. The lower areas of the northern slopes are fine if they are hilly or mountainous (or facing south if you are in the southern hemisphere).
As for the pH of the soil, walnut is quite adaptable. The best soils have a pH between 6.0 and 6.5, but even 5 to 8 are pretty good
Step 3. Clean up the area
Remove existing vegetation from the site you spotted before planting walnuts, as it would compete for the same nutrients with other trees. If you want to plant a large orchard, you need to aerate the soil before thinking about cultivation.
Step 4. Plant the walnuts in small holes
Dig holes about 5-7.5cm deep and insert the walnuts on their side, then fill them with potting soil. If you want to plant more trees, space the holes 3.0-3.7m apart in a grid pattern.
- Alternatively, you can plant two or more walnuts in each hole 20cm apart. When the seedlings have grown for a year or two, leave the healthiest one in each spot and remove all the others.
- Read the “Tips” section to learn about an alternative method of planting seeds while protecting them from squirrels and other small animals.
Step 5. Take care of the seedlings that are growing
Read the next section for information on how to care for growing seedlings and trees. Skip the steps that describe how to bury them.
Part 3 of 3: Planting Walnut Trees and Caring for Them
Step 1. Choose seedlings (if you don't want to grow them from nuts)
Measure the diameter of the seedlings about 2.5 cm above the root crown, where the roots meet the trunk. Choose those with a minimum diameter at this point of 0.6 cm or even larger if possible. This is the most important measure for predicting quality.
- Bare root seedlings, sold without soil, should be planted in spring, before bud growth and immediately after purchase.
- The seedlings you take in containers can also be planted later, in dry periods and soils, but they are generally much more expensive.
Step 2. Plant the seedlings in the spring
Choose well-draining clay soil and avoid steep, hilly slopes. Place the seedlings in holes that are at least double the size of the diameter of the roots and deep enough to completely bury the root system. For best results, fill holes with one part of compost for every three parts of normal soil. Press the soil carefully and water thoroughly.
Keep the seedlings at a distance of 3, 0-3, 7 m from each other to allow them to grow well
Step 3. Water from time to time
At least during the first two years after planting, whether you have planted walnuts or seedlings, this plant requires watering frequently, especially during the dry and hot season. Water it abundantly, but not before the soil is dry again. If you wet it too much, it can harm its growth.
After two to three years, the trees should only be watered during the hottest months or during a dry spell, about once or three times a month
Step 4. Deal with weeds
Care for the seedlings by keeping the surrounding area clear of sod and weeds, as they compete with small nuts for soil nutrients. Remove them by hand or install a fabric barrier. At the base of the larger seedlings, you can apply mulch to keep weeds at bay, putting a layer about 5-7.5 cm above the root zones.
Do not mulch plants that have not yet emerged from the soil, as it may block the growth of the sprout. Wait for the seedling to become a bit woody and have developed roots
Step 5. Learn how to prune walnuts
If you are growing these plants for lumber, it is important to start pruning them early to ensure a straight trunk, leaving a "main" branch at the top of the tree and giving it an always straight direction in the next two growing seasons. The seedlings grown as a fruit tree do not need special care until after thinning, but it is recommended to prune them later if it is black walnuts, since usually, in the end, these are also sold for timber, as well as for the variety of nuts.
- If you've never pruned trees before, especially those that are still small, you should find an experienced gardener who can help you identify the main and most important branches.
- If the upper part of the tree has two large main branches, fold the best one upright and tie it to other branches that support it, then cut the tips of the supporting branches to prevent their growth.
Step 6. Thin the trees to select the best specimens
Most orchards start with more plants than the area can support. When the trees get large enough and the branches begin to intersect each other, you need to choose the healthy trees that have the best characteristics, usually a straight trunk and rapid growth. Remove the others, but don't leave too much empty space as weeds or even other trees could grow and compete for nutrients.
You can use these tips on how to thin out trees; however, the internet offers many other suggestions
Step 7. Apply fertilizer only when the tree has grown in size and is no longer a fragile seedling
Fertilizing walnuts is still a rather controversial topic, at least for black ones, because it can facilitate the development of competing weeds even more than that of the trees themselves, especially if the soil is already rich in nutrients. Wait until the log has reached the size of a "pole" or is at least 10cm in diameter at 1.4m high. The best thing to do would be to send a sample of soil or leaves to an analysis laboratory to identify the exact nutritional deficiencies. If this is not possible, apply fertilizer to each tree in late spring containing 1.5 kg of nitrogen, 2.5 kg of triple superphosphate and 4 kg of potash. Leave a few trees without fertilizer to compare the effect and, if positive, reapply every 3-5 years.
Analyze the pH of the soil after fertilization, to see if it needs to be adjusted and brought back to normal levels
Step 8. Check for parasites or other pests
Squirrels in hazelnut trees are very easy to see, and they can destroy an entire crop of nuts if not kept in check. Cover the logs with protective plastic to prevent them from climbing up and sever branches less than 1.8m above the ground if you are able to do so without creating knots that could decrease the value of the timber. Other pests such as caterpillars, aphids and flies vary by geographic area and may not harm trees if they are active later than the growing season. Consult a local forest ranger or experienced walnut farmer for information specific to your region.
Keep livestock away from trees of any size, as the damage they cause could make all your farming work in vain and annihilate the value of the wood
Advice
To protect the seedlings from small animals, interred in cans. First it burns the metal so it will disintegrate within a few years. Remove one end and create an X-shaped opening in the other end using a chisel. Put 2.5-5 cm of soil inside the can and bury the seedling inside the jar. Now bury the can with the "X" side at the top 2.5cm below ground level. The walnut will be protected and will sprout through the top of the can
Warnings
- If harvested walnuts dry out too much or are removed before the layering process is complete, it may take an extra year before they begin to grow or they may fail to fully develop.
- Walnut leaves can spread chemicals into the air that kill other plants. Collect them and compost them until they completely degrade, to make them safe if you want to use them as mulch.
