The black walnut tree (Juglans nigra) is native to the midwestern and eastern U.S. and is prized for its hardy growth--the tree thrives in even sandy or clay soils, according to the University of Wisconsin--and its high-quality lumber. Though you can sometimes buy black walnut seedlings in nurseries, save money by collecting and growing a black walnut tree from nuts.
Collect nuts from beneath a black walnut tree. Nuts usually start falling in the months of September and October, according to the University of Minnesota.
Soak the nuts in a bucket of water for two to three hours. This softens the nuts' husks. Use a knife to peel back a portion of the husk, then peel off the rest with your hand.
Drop the peeled nuts back into the water. Retrieve the nuts that sink and throw away the nuts that float. Nuts that sink have a greater germination rate, according to the University of Minnesota.
Allow the nuts to dry out for 24 hours, then place them in a sealed plastic bag and put them in your refrigerator. Store the nuts in your fridge for three to four months. This mimics the winter temperatures and helps bring the nuts out of dormancy.
Prepare the outdoor soil as soon as the ground thaws after the winter. Select an open, sunny area and use a spade to break up the dirt to a depth of 6 to 8 inches. Stir in a couple inches of aged compost. Though black walnuts are tolerant of poor soil, they thrive best in dirt that's rich in organic matter.
Plant the nuts. Bury two nuts in each planting spot, sinking the nuts an inch under the soil surface and separating them by a couple of inches. If you want to grow more than one black walnut tree, space each planting spot apart by 20 feet.
Water the soil twice a day or as needed to keep the soil moist. Apply enough water to moisten the dirt to a depth of at least 3 inches. The nuts will germinate within five weeks. Once the seedlings are 2 to 3 inches in height, pull out the seedling that's the smallest and thinnest.
Things You Will Need
- Black walnut nuts
- Plastic bag
- Aged compost
- Black walnuts are hardy down to USDA zone 4. For the best results, grow nuts collected from black walnut trees growing in your area. These nuts will germinate and grow better than nuts that aren't used to your region's climate and soils, according to North Dakota State University.
- Black walnut trees produce a chemical called juglone that kills nearby plants, according to Purdue University. Don't grow your black walnuts near your garden or any desirable vegetation.