In Minnesota, black walnut trees are usually ready for nut harvest from August through September. Follow the tips in this message to learn how to harvest them.

Allow nuts to ripen on the tree. The husk changes from solid green to yellowish green when ripe. Press on the skin of the walnut with your thumb. Ripe nuts show an indentation.

Walnuts discolor when stored with husks attached and their flavor is ruined. Wear gloves when removing husks because dye from the husks stains. Remove husks by applying pressure to the nut's ends. Pound side to side with a hammer while wearing safety glasses. Husks also can be softened in a container of water, then peeled. A third alternative is to place nuts in a hand-operated corn sheller.

After hulling, rinse the nuts, preferably outdoors since nuts stain. Next, check for insect feeding by placing the nuts in water. Nuts without injury will sink.

Do not compost walnut husks. Juglone, a chemical released by walnut trees, is toxic to some vegetables and plants, such as tomatoes.

Curing--The nuts must be cured. This prepares them for storage and allows flavor to develop. Stack the clean, hulled nuts in layers two or three nuts deep. Place them in a cool, dry, well-ventilated area, out of direct sunlight for two weeks. When nuts are dry enough to store, kernels break with a sharp snap. If cured improperly, mold forms.

Storage--After curing, store unshelled nuts in a well-ventilated area at 60 degrees Fahrenheit or less. Cloth bags or wire baskets discourage mold. Keep the relative humidity fairly high, about 70 percent.

To shell nuts, soak them in hot water for 24 hours. Drain and soak again for two more hours. Cover the nuts with moist cloths until you're ready to crack the shells. Bake nuts at 215 degrees Fahrenheit for 15 minutes. If stored at room temperature, use within a few weeks. Shelled nuts can be refrigerated up to nine months. They can be frozen for up to two years.

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