How Do I Start a Black Walnut Tree From Seed?

Test the soil in a chosen site that has full sun and good drainage. The ground also needs to be at least 3 feet deep to accommodate the black walnut tree's long roots. The University of Missouri Center for Agroforestry recommends the soil test to find out the area's soil pH and nutrient content. Your extension office either performs the test of has a list of labs that do. The test result includes specific recommendations for amending your soil, including the type of amendment and how much of it your topsoil needs.

Break up the soil in fall and remove weeds and grass. Incorporate compost, manure or other organic matter into it. Add the amendments that were recommended in the soil test results. Let the soil absorb the nourishment until next spring while you get the black walnut seeds ready.

Gather black walnuts when they ripen and fall to the ground around September or October. Plan to sow a few nuts even if you only want one walnut tree, as often not all seeds germinate. Later, you'll have a chance to thin the saplings to the number of trees you wish to grow.

Soak the nuts in a bucket of water for a few hours. This softens the husks, making it easy for you to remove them by hand.

Put on gloves and some old clothing to husk the nuts. Black walnut hulls release a stain that ruins fabric and takes a while to leave your skin and nails.

Place the husked nuts in a bucket of water. Discard any black walnuts that float to the top and keep the others.

Add enough moist sand to a plastic bag to cover your black walnuts.

Place the walnuts in the bag of sand, seal it and put it in the refrigerator for the next four months. This chilling process is called stratification and it is necessary for nuts to germinate.

Check the bag of black walnuts once a week to verify that the sand is still moist. If it seems to be drying out, add a little more water to the bag. The nuts need a moist, but not soggy, environment during stratification.

Dig 2-inch-deep holes in spring, 2 feet apart, one for each of the walnuts you intend to plant.

Remove the nuts from the refrigerator and transfer them from the bag of sand to the holes you made outside. Cover them with topsoil and tap the surface with your palm to remove air pockets.

Irrigate the seeds thoroughly at planting. Continue to keep the ground moist through the growing season.

Cover the soil surface over the seeds with a pile of fresh cow manure. The USDA Forest Service says it deters squirrels.

Feed each black walnut seedling 1/4 cup of a slow-release fertilizer in mid-July to boost root and wood development.

Thin the black walnut saplings after the first growing season. Cut their trunks below the root collar with a sharp garden spade or another blade. Then dig underground to remove the root balls.