Author Topic: Bad wood mulch?  (Read 302 times)

Offline sgeiler

  • Fledgling Prepper
  • *
  • Posts: 2
  • Karma: 0
  • New TSP Forum member
Bad wood mulch?
« on: October 12, 2017, 11:54:10 AM »
I've looked all over the internet and I believe I heard a related question on the show a while back but I can't seem to find it again...
Last fall I had a black locust tree cut down and the stump ground. I decided this spring to take the grindings and put a layer on my raised beds.  None of my plants in those beds produced. All the plants just stopped. Still looking healthy for the most part but no new growth. Tomatoes, peppers and cucumbers mostly.
So, I'm thinking it could've been the trunk and root chips in the soil...
That being said, I still have a nice sized pile of branches and leaves that were run through the grinder. I was thinking about starting a back to eden garden in another part of my yard to experiment but I'm worried about using this mulch. Anyone have some wisdom to share?
Thanks,
Shannon

Offline Skunkeye

  • Dedicated Contributor
  • ******
  • Posts: 1603
  • Karma: 90
Re: Bad wood mulch?
« Reply #1 on: October 12, 2017, 12:32:03 PM »
Black locust is reportedly somewhat allelopathic - this means that the plant produces chemicals than can suppress the growth of competing plants.  Not a lot of studies have been done on locust, but I recall one for certain that found that the leaves contained certain chemicals that caused very slow growth in various species of plants.  It's not as bad as, say, black walnut, which is notoriously allelopathic (the chemical black walnut produces is called juglone, and it's especially effective on tomatoes, potatoes, and anything else in the nightshade family).

Black locust is very rot-resistant, which means it probably wouldn't be great for a "Back to Eden" garden even if it didn't slow plant growth.  That's because you want the mulch to break down and feed the soil.  If you use something that takes 4-5 times as long to rot, your soil will develop much more slowly.  If you want to use the locust chips, I would suggest letting them sit for a year (possibly turning the pile every month or two), and letting rain and air help wash out and break down any allelopathic chemicals that the wood contains.  I would also probably only use it as a top layer of mulch, and put another layer of faster-decomposing wood chips (pine, mixed hardwood, etc) under that, directly in contact with the soil.  That way the bottom layer will start building the soil, and the locust on top will be a long-lasting layer to help hold in moisture.
"The Constitution is not an instrument for the government to restrain the people; it is an instrument for the people to restrain the government - lest it come to dominate our lives and interests.” - Patrick Henry

Offline sgeiler

  • Fledgling Prepper
  • *
  • Posts: 2
  • Karma: 0
  • New TSP Forum member
Re: Bad wood mulch?
« Reply #2 on: October 12, 2017, 10:22:41 PM »
That is pretty much what I was thinking.. I just couldn't find much for evidence to support it. I didn't even think of the rot resistance being an issue though. So glad I asked.