The walnut is an edible seed of any tree of the genus Juglans, best known of which is the Persian walnut - Juglans regia, although in North America you could argue that it is in fact the native Black Walnut.
All types of walnuts are quite hardy, and actually require a cold winter period in order to thrive. So anyone living in warmer climates won't have much success with their own walnut trees.
Walnuts will start to produce nuts at around 10 years of age, give full production at 30 years and keep on producing for more than 50 years. Depending on the specific variety of the walnut tree, they can grow up to 100 feet in height.
The walnut nut
Walnut seeds are high density source of nutrients, particularly proteins and essential fatty acids. Like other tree nuts, walnuts must be processed and stored properly. Worryingly, poor storage makes walnuts susceptible to insect and fungal mould infestations; the latter produces aflatoxin - a potent carcinogen. Mould infested walnut seed batch should not be screened then consumed - the entire batch should be discarded.
The seed kernels - commonly available as shelled walnuts - are enclosed in a brown seed coat which contains antioxidants. The antioxidants protect the oil-rich seed from atmospheric oxygen so preventing rancidity.
As mentioned previously there are two major varieties of walnuts grown for its seeds — the English walnut and the Black walnut. The Black walnut is of high flavour but due to its hard shell and poor hulling characteristics it is not grown commercially for nut production. The commercially produced walnut varieties are nearly all hybrids of the English walnut.
How to grow walnut trees
If you are planting walnuts as garden trees, space the plantings about 60-70 feet apart so their crowns can develop a majestic spread as they mature. However, if you're planting black walnuts for their valuable wood, plant them about 30 feet apart so their trunks will grow long and straight.
Planting the seeds If you choose to start your walnut tree from a seed, you will want to either plant your seeds where you want your final tree, or transplant it while very small. Walnuts do not do well at all in containers because of deep tap roots and don’t handle transplanting.
You can plant with or without the husk still on, though taking the husk off will help the plant germinate. Plant your nuts in the fall, and protect them from squirrels. They need a period of cold before they will sprout. It only needs to be about 3 inches under the soil. They should sprout in 4 to 5 months, or possibly not until the following year.
Gather the nuts as they fall from a tree in your area, and remove the husks. Place half a dozen nuts several inches apart in a cluster, four or five inches deep. If you have squirrels, lay a piece of hardware cloth over the planting spot and pin it to the ground with v-shaped wires. Lay a mulch of straw or leaves over the hardware cloth to reduce the freeze/thaw cycles. Mark the site so you can find it again. After autumn planting and a session of damp, cold weather, the walnut seeds will germinate in the spring. Remove the mulch and hardware cloth from the planting spot in late winter, and mark the spot clearly so you don't accidentally mow over it!
After the baby trees have grown for a few months, choose the best one and eliminate the others. caring for your walnut tree.
Caring for your walnut tree
Full size trees have very long and deep root systems, which usually can protect them from moisture problems on the surface. But after very prolonged periods of drought, your trees might need some watering. You can end up with 'burned' walnuts come harvest time if you let your trees get too dry for too long. Walnut trees should be left to grow naturally without pruning.
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