English walnut trees are tall and majestic, spreading out to form large canopies, when fully mature. The nuts they bear are familiar to many and trees can be grown from the seed inside. Their size demands they be grown outdoors. Before starting an English walnut tree from seed, ensure that one will grow well in your area. They prefer cooler climates and do best in hardiness zones 4 through 6.
English walnut seeds need a certain amount of time in cold conditions to germinate, known as breaking dormancy. With some special preparation, you can grow an English walnut tree from seed.
Starting English Walnut Seeds
Get some English walnuts from a nearby tree, unshelled nuts from your grocery or farmer's market or from commercial sources such as seed companies.
Ensure the nuts are fresh and free of damage or disease. Sterilize the outside of the nuts by dipping them in nearly boiling water for 1 minute.
Break the dormancy of the seed inside the nut. Follow either of the methods below to break the dormancy of your seeds.
If you live in areas where temperatures drop below 40 degrees F for at least 60 days, plant your walnuts, shell and all, directly in the ground in the fall. Plant seeds 4 inches deep in fertile, well-drained soil with plenty of sun.
If the temperature in your area is not suitable for planting in the fall, or you want to plant in the spring or start indoors, place nuts approximately 2 inches deep in a container filled with half peat moss and half sand. Refrigerate the nuts for 60 days. Keep the soil from drying out to encourage germination.
Once you have broken dormancy, plant the seeds, still in the nut, either outdoors after the last frost of spring or indoors at any time. Plant seeds 4 inches deep in fertile, well drained soil with good sun exposure.
Watch for growth in 4 to 6 weeks. As your English walnut grows, continue to water and feed it with a nut tree fertilizer.
Train your English walnut trees, as they mature, by pruning and thinning to develop a strong framework to better support fruit and open the canopy for better light penetration, pollination and harvesting.