No, you shouldn’t compost walnuts or walnut shells – at least not in any great amount.
Walnut trees release a chemical called juglone which is toxic to some vegetables and plants, such as tomatoes so it is best to avoid composting anything related to walnuts in case you want to use the resulting compost with susceptible veggies.
The shells from a handful of walnuts isn’t going to cause a huge problem in a big compost heap but if you’re got a lot of shells or nuts to get rid of, it would be better to look for an alternative method of disposal.
the advice about walnuts being compostable or not was good. I never would have thought about it one way or the other. Thanks
i have 2 cooked nuts. Will they harm the compost heap?