Soils and nutrition management for black walnuts

Although walnut may survive when planted in unsuitable soils, most likely growth will be slow and the trees will be of poor quality. Sufficient time should be spent locating quality sites for this valuable and high-site demanding species. Undoubtedly, only ideal soil conditions will allow for adequate root expansion and for soil levels of nutrients and water to be sufficient for consistent growth and nut production. Nitrogen (N) is often the limiting nutrient to tree growth. Fertilization of young walnuts for growth is usually offset by an increase in vegetation competition from weeds. Benefits from fertilization are more likely before crown closure, after thinning, and for active growing large-diameter trees a few years before harvesting. Greater payoffs from fertilization can likely be expected from nut production, especially for trees of nut varieties with larger and more consistent nut crops.