Experience with walnut mulch?

I have the opportunity to get some very convenient and cost effective mulch from a local producer. It’s a lumber company that deals exclusively in walnut wood, including the dreaded back walnut.

Reading around, a lot of info is saying that the leaves, roots, and fruit of the black walnut contain the majority of the Juglone chemical that inhibits the growth of SOME plants (most of mine listed as immune, but not all) And that this chemical degrades with exposure to the air. The safe-side recommendation is to compost the mulch for 6 months before using.

I need mulch down sooner than later. My beginning food forest trees and bushes are all surrounded by cardboard so I feel like it’s safe to use this black walnut mulch since it will be over 6 months until even the cardboard breaks down and lets the mulch contact the soil. And It seems to me like spreading it out would expose it to the air faster than leaving it in a pile.

Anyone out there with experience with this? Would you go for it?

For more details on my particular garden:
https://permies.com/t/111632/critique-food-forest-plans#912890

I know no science on this subject. But I know lots of folk lore. I would never use walnut on gardens or for animal bedding. Several hundreds of years of farmer experience informs me so. You are wanting to try a short cut for convenience sake. I suspect you are risking it ending not well.

Get a bucket of it, plant some radishes, squash, and wheat into it. Watch how they grow for a week or two.  They are quick to germinate in normal circumstances, so it will give an idea about how the walnut mulch might work. Just because it works once, doesn't mean that you'll get a non-poisonous batch next time, but it's a data point. If it doesn't work the first time, then that'd explain why the mulch is so inexpensive....

The local CAFA here sells compost/mulch made from bedding and manure. It is rather inexpensive. People tell me that it sometimes damages their gardens, so I recommend that the compost from the CAFA not be used. You might find something similar with the walnut mulch.

Doing a trial planting as Joseph mentioned is always a good idea with unknown mulch material, especially now that most have had the opportunity to be sprayed with something.

Historically walnut has been used as a mulch for pathways because of its ability to prevent germination and weakening growing plants.

Composting does help and there are no real short cuts that work, including cardboard. The problem is rain, it soaks the mulch which soaks the cardboard which leaks water to the soil below.

Redhawk