There's always one day in October when the wind starts blowing hard and walnuts start falling from the trees. Those are dangerous days. Don't go under the trees unless you have to - and if you get caught, hug the trunk. You're less likely to get hit if you're hugging the tree.
You'll look silly, but it's true.
Walnuts are great dye plants. Gather them now and keep them in a bucket until you're ready to use them. Keep the bucket covered and outside. They'll start to wither, then turn black, then ooze and the smell is a lot less than pleasant. Collecting natural dyestuff can really test your intestinal fortitude. Yep.
You can use these to dye any time. You can dye with them now or wait until they're black and oozing or wait until they've freeze dried all winter. No matter. They'll dye beautifully.
These are the colors we got on [L-R] cotton, alpaca, silk, wool, superwash wool. Beautiful browns.
What you do is soak the walnuts overnight in a pot of water. The next day, boil the whole thing for an hour and then let it sit overnight again. On the third day, strain out the walnuts and dye your fiber.
If you're using really fresh walnuts - oozy and black - then you can just boil it all the first day and let it sit over night. Skip the first soak.
You can also fill a bucket with walnuts and drop your fiber in there and just leave it in the sun for a few days. It'll be splotchy, but beautiful.