Crushed dolomite limestone is used to correct this condition and reduce acidity of soil. Prune any suckers that come from below graft on trunk. In orchards, trees over 15 years old may be interseeded with grasses and legumes and animals turned in to pasture, as they will not damage older trees. All black walnuts tend to bear heavy nut crops every second year. No cultural practices have been developed to offset this type of alternating.
Some trees bear every year, while others bear every third year.
Others mainly react to climatic conditions with no pattern. Varieties are selected for each area. When trees bearing fruits of exceptional quality are found, they are propagated and cultivated for nut production in that area. Harvesting Nuts are havested from native trees as well as from improved selections and cultivars. Fruit ripens in one season, usually by late September or early October.