I have black walnut trees and this is the first year they have produced nuts. However, the nuts are soft with nothing inside. Any suggestions?
I assume you intend to eat these nuts. If so, you can’t eat them as soon as they fall from the tree.
When black walnuts fall the nut inside is soft and milky. It takes a couple of months until the nutmeat has cured enough to store or use in recipes. When you gather the nuts, use gloves because the husks will stain anything they touch. Remove the husks once they have turned black and dried. It could take two months. Store them in a dry, warm place. After a month of storage, check the nutmeat to see whether it’s firm. You can extract the nut from the shell using a hammer or nut cracker.
For general information about the black walnut (Juglans nigra), please see the Toronto Master Gardeners’ article at https://www.torontomastergardeners.ca/index.php/factsheet/juglone-and-black-walnut-a-toronto-master-gardeners-guide/