August - September
The black walnut (or eastern black walnut) tree is native to the Midwest and is more frost-resistant than the English walnut (which the English call the Persian walnut). Black walnuts have a robust flavor and are delicious in baked goods.
If foraging for black walnuts, look for yellowish-green husks and wear gloves when harvesting since the juice will leave a black stain (hence the name). Nuts ripen at different intervals, so visit your tree often over a period of a few weeks. Black walnut husks are notoriously difficult to remove, often requiring a hammer and safety glasses, but the work is worth the result. Do not drive over walnuts with a car to hull them—this can be very dangerous to bystanders. After hulling you’ll be left with what is commonly recognized as a walnut in its shell. After hulling, the nutmeat must be cured (see Storage).
Nutrition: Walnuts provide 94 percent recommended daily value of the important and hard-to-get omega-3 fatty acids, which research suggests may reduce inflammation and may help reduce the risk of heart disease. Walnuts have also been shown to reduce high cholesterol levels and may act as an anti-inflammatory when consumed daily. Like most tree nuts, walnuts are a high-calorie food due to their fat content (although it's the "good" fats), so it's a good idea to measure your servings - one serving is about 1/3 cup or a small handful. A daily serving is a good way to improve your body's nutrition and curb those afternoon snack attacks. Try sprinkling chopped walnuts onto salads to increase your body's absorption of the nutrients from vegetables.