Thursday, March 7, 2013

Could Black Walnut Leaves Ruin Your Finished Compost?

EeeeK! Tomato plants RUN FOR YOUR LIVES! It’s the horrible, abominable, monstrous Black Walnut leaf!!!

In all seriousness, Black Walnut trees create a chemical called juglone that really is toxic to many plants we grow, like tomatoes, blueberries, and azaleas. So will the leaves from Black Walnut trees create a toxic compost causing our favorite plants to bite the dust?

No. The OSU Extension says the toxin in these leaves breaks down within 2 to 4 weeks of composting. Let the leaves thoroughly break down in your compost bin and you’ll be fine.

Really, relax.

Woodchips and nut shells from Black Walnut do require a longer period to decompose, so give them at least six months to break down before applying the compost to sensitive plants.

Still nervous your applying a kiss of death with your compost?

You can test the finished compost by planting a few tomato plant seedlings and see if they survive. If sacrificial experiments are not your thing, you can always use the finished compost on the many plants not sensitive to our Black Walnut friends. OSU provides a handy list of these plants as well.

Have you ever composted Black Walnut leaves? Let us know how it worked out in the comments.

Yes, this is poison ivy, but I couldn't resist scary leaf clip art.

1 comment:

  1. Nancyparsons1750@att.netAugust 22, 2017 at 10:59 AM

    While bagging up compost I started a decade ago,I noticed a lot of walnut shells. I believe the squirrels hid them there after i added leaves. Where I had added compost to a new experimental garden, fifty feet from dripline of black walnut tree, I have four tomatoes plants, two of which I had to top off after they pulled the cages out of the ground and each have at least 50 beefsteak tomatoes on now. My mandevilla has had at least 25 blooms all summer, but the neon pink turns white before falling off. I think my bartzilla penny is dead.