Black walnuts are widely grown for both ornamental and utilitarian purposes, according to Kansas State University. The hardy trees will thrive in a variety of soils and can provide shade as well as edible nuts. Instead of buying started saplings in a nursery, which can often be expensive, plant the black walnuts themselves for your own miniature walnut forest.
Ready the black walnut nuts for planting. Soak the nuts for 24 hours in water to soften their husks. Peel off the husks by hand, then place the nuts in a sealed plastic bag in your refrigerator for three to four months. This helps bring the nuts out of dormancy, according to the University of Minnesota.
Prepare the planting site. Black walnuts thrive in loose, deep soil, according to Kansas State University. Use a spade and breakup the ground to a depth of 36 inches. Mix in 4 to 6 inches of compost to improve the soil condition and boost drainage.
Test the soil pH using a testing kit available from many garden stores. Black walnuts grow best when the pH ranges between 6.5 and 7.2. The pH can be raised or lowered using amendments like agricultural lime, slaked lime, urea phosphate and various nitrates and sulphates. The exact amount needed varies according to how much the pH needs to be adjusted. Consult your regional cooperative extension office (see Resources) for further guidance and to determine what pH amendments are commonly used in your area.
Bury two to three nuts in the planting site after they're done being refrigerated. Sink each nut a couple inches away from each other and 2 inches below the soil surface. Kansas State University says black walnuts often have a 60 percent germination rate, so planting more than one nut makes likely at least one black walnut seedling.
Water the planting area once a day with enough water to moisten the soil to a depth of 3 to 4 inches. The black walnuts will germinate within five weeks, according to the University of Minnesota. If more than one seedling emerges, uproot all of them except the tallest and strongest one.