In her books, she said try to pick your black walnuts on or off the tree and at least 1/2 green!
Why? Simple, southern California not so great for Black Walnuts Trees. She literally drove a pick up truck out of state, used a scoop shovel and through the walnuts in the back of the truck and drove them back to California!
I knew one of the best Master Herbalist in the country, I asked him about black walnuts and he sent me the 1940's German Black Walnut studies! The German Studies said the okd walnuts has less de-wormer qualities!
Baby Black Walnuts were the Best and The Best of the Best come from the 65+ feet tall trees and picked from the North Side of the tree!
The Superior use of the Black Walnut Tree for a "De-Wormer" Herb source?
MH