Is black locust wood ash safe?

January 17, 2017

Has anyone here tried black locust wood ash on tomatoes? Did it kill them, or work just like other wood ash?

I heard black locust has allelochemicals. So, I thought I'd ask to make sure it's safe.

Seeing as black locust is prized for firewood, I imagine it's possible someone has tried it.

Edit: I see now there's a soil building forum. Is this post off-topic here? Can it be moved?

Worth1 · January 17, 2017

What do you want to use the wood ash for?
The potassium or to raise the pH, it will do both.
I have no idea if it will hurt the plants.

bjbebs · January 17, 2017

I burn a lot of black locust. The ash goes to the garden along with other hardwoods. It's one of the best for heating and perfectly safe when tilled in.

Gardeneer · January 17, 2017

IMO, the allelochemicals will not survive the temperatures of fire. Allelochemicals , if I am not mistaken are some kind of acid or oil, like aromatics.

January 17, 2017

Awesome. Thanks, everyone!

@Worth1

I want to use it mostly for the potassium, but also for calcium and whatever else is in it. I used wood ash in 2016, but not black locust wood ash. I like to use peat moss along with it to help it so it doesn't raise the pH too high. There was too much wood ash around trees and stuff in 2014/2015 (without peat moss), and it made the pH and/or potassium way too high, such that they turned yellow and/or became stunted. (I didn't put it there.) We cleared out some of the affected plants and a tree, and I mixed peat moss in for the watermelons I grew there in 2016. They did just fine, all things considered.

We had a lot of potassium for our tomatoes, in 2016 from the wood ash, and it seemed to help quite a bit. However, we didn't put any where the squash and tomatillos were (I did put peat moss there). The squash struggled (except for Dark Star zucchini and sort of Tatume) and I think low potassium may have been the issue. I'm planning to grow some of my tomatoes there this year, though. That's where I want to put the wood ash.

dirtdigging101 · January 20, 2017

Be careful wood ashes can be very dangerous to your health and I would never use them in the garden. Why? Trees assorb lots of things including metals like Al and things like arsenic all influenced by acid rain mostly. burn the wood and these things concentrate in the ash.

This was realized back in the 70's by a doctor who had several patients all sic, all burned wood had big gardens and canned a lot. He, the doctor finally figured it out this happened in the southern part of NY state. No one died but they did not feel well.

January 17, 2017	#1
shule1 Guest Posts: n/a	Is black locust wood ash safe? Has anyone here tried black locust wood ash on tomatoes? Did it kill them, or work just like other wood ash? I heard black locust has allelochemicals. So, I thought I'd ask to make sure it's safe. Seeing as black locust is prized for firewood, I imagine it's possible someone has tried it. Edit: I see now there's a soil building forum. Is this post off-topic here? Can it be moved? Last edited by shule1; January 17, 2017 at 04:07 AM.

January 17, 2017	#4
Gardeneer Tomatovillian™ Join Date: Feb 2015 Location: NC - zone 8a - heat zone 7 Posts: 4,919	IMO, the allelochemicals will not survive the temperatures of fire. Allelochemicals , if I am not mistaken are some kind of acid or oil, like aromatics. __________________ Gardeneer Happy Gardening !

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January 17, 2017	#2
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	What do you want to use the wood ash for? The potassium or to raise the pH, it will do both. I have no idea if it will hurt the plants.

January 17, 2017	#3
bjbebs Tomatovillian™ Join Date: May 2014 Location: illinois Posts: 281	I burn a lot of black locust. The ash goes to the garden along with other hardwoods. It's one of the best for heating and perfectly safe when tilled in.

January 17, 2017	#5
shule1 Guest Posts: n/a	Awesome. Thanks, everyone! @Worth1 I want to use it mostly for the potassium, but also for calcium and whatever else is in it. I used wood ash in 2016, but not black locust wood ash. I like to use peat moss along with it to help it so it doesn't raise the pH too high. There was too much wood ash around trees and stuff in 2014/2015 (without peat moss), and it made the pH and/or potassium way too high, such that they turned yellow and/or became stunted. (I didn't put it there.) We cleared out some of the affected plants and a tree, and I mixed peat moss in for the watermelons I grew there in 2016. They did just fine, all things considered. We had a lot of potassium for our tomatoes, in 2016 from the wood ash, and it seemed to help quite a bit. However, we didn't put any where the squash and tomatillos were (I did put peat moss there). The squash struggled (except for Dark Star zucchini and sort of Tatume) and I think low potassium may have been the issue. I'm planning to grow some of my tomatoes there this year, though. That's where I want to put the wood ash.

January 20, 2017	#6
dirtdigging101 Tomatovillian™ Join Date: Jan 2007 Location: north carolina Posts: 67	Be careful wood ashes can be very dangerous to your health and I would never use them in the garden. Why? Trees assorb lots of things including metals like Al and things like arsenic all influenced by acid rain mostly. burn the wood and these things concentrate in the ash. This was realized back in the 70's by a doctor who had several patients all sic, all burned wood had big gardens and canned a lot. He, the doctor finally figured it out this happened in the southern part of NY state. No one died but they did not feel well.