Burn pile into huglebed?

When I moved, there was a large burn pile over 2 feet tall and probably 6 or 7 feet wide on the property. Since then it's been the go-to where I throw fallen branches from the river birch & pecan tree. Last year I noticed a watermelon vine growing out of it, so I let it grow, got 3 small but tasty melons! Anyway it's about 6 feet tall now from all the dead and fallen branches I've tossed on there. My neighbor keeps bugging me telling me to go ahead and burn it already, he's worried about copperheads, but it's too close to other trees, close enough to definitely singe if not catch them on fire, (he already caught my yard on fire once! Long story. But I'm not trying to do it again!)

So I started thinking with the volunteer watermelon growing out of there - could I just cover the whole thing with top soil and turn it into a huglebed? There was be a lot of air pockets, but I assume they'd decompose eventually and I could shovel things around or add more dirt if I had too. I live in coastal Carolina zone 8 and really want to grow some mullein for tea and thought that might be a good place to goes it since up north it's always found on sloping land.

Looking for advice on if I could keep it simple and just bury it, of that would work? And how the ash underneath may change things? Thank you for all y'all's wisdom!!

Hi Sarah,
I am not a hugelkultur expert. In fact, I have never even built one myself, though I have seen videos and read articles about it. So take this with a grain of salt.

One big difference between simply covering it with dirt and building one specifically... would be the structure. A built hugelkultur has the branches and logs laid in certain ways to make it more stable. If you simply covered it with dirt, I think it would probably work, but you may need to deal more with erosion on the sides and the potential for sink holes while harvesting things.

Hi Matt, thanks for your reply. Those are two things I didn't think of! Erosion & sinkholes. I'm kind of a long that train of thought too, that it could probably work okay enough" for mullein anyway, I'd think. Lol. I've read some stuff about it before and did see that the practice is a bit specific on the way they're built from the "in-ground upward. So I guess I couldn't call it a proper hugle bed, but I suppose if I do decide to cover it with dirt I'll put some updates on here and let people know how it turned out!

I have used partially charred wood in hugels, with seemingly good results. I’d be concerned about gick (plastic, accelerants, etc) having been burned in there before. If that is not a concern, I might consider reducing the amount of concentrated ash, maybe with a leaf blower. The acidity of your soil and the ph preference of plants you want to grow would be a consideration too, as ash will make it more alkaline.

It sounds to me like you have the makings for a 10 year hugel instead of a 30 year hugel.  I don't see a problem with that. The more it can be crushed down & the gaps filled with soil the more stable it will be in the long run. Just add more soil into the empty spaces if & when it does collapse as the wood breaks down. There are many excellent nutrients in wood ash but as with most things moderation is the key. You could try removing some as Ben suggested. Since it's on the bottom of a 6 foot tall pile of wood it might not be much of a concern. Mullein prefers poor alkaline soil. So adding dirt might be a great thing to grow on it until the decomposition process turns it into actual high quality soil. Then you can grow huge watermelons on it!!!

From my experience with burn piles is that I see nothing beneficial to the hukel from a burn pile, though it depends ...

A burn pile is not the same thing as biochar.

Just yesterday, I was looking at the spot where the former owner had a burn pile from before 2013.

When we bought the place there were some remnants of building debris mostly wood and gypsum.

Nothing will grow there, no weeds or grass ... over 12 years.

If the burn pile contained the same kind of wood that biochar is made from and nothing else then maybe that would work.

Just to clarify, I believe the OP has a large stack of branches and/or logs. I don't think anything has been burned here because it is so close to the woods. So the burned parts should not be an issue.

Thank you for all the great replies everyone and the support to go for it Mike! Lol.

Thanks for mentioning the ph Ben, that's definitely something for me to keep in mind!

From what my neighbor has told me, the burn pile was used to burn fallen branches and leaves. My neighbor was the last one to use it before we bought the property, he burned some branches last year and caught all the grass on fire! When we came to the property it was only a couple weeks after and the ground was black with ash & and tree next to the pile lost half of its leaves. So it's definitely time to retire the burn pile, lol! The watermelon vine came back this year, but no melons. I'm not familiar with biochar, but there is a bunch of stuff growing out of it like wild lettuce, sow thistle, dog fennel and some other stuff growing out of the side that gets the most sun. I figure I don't know what else to do with it, so i thought it would be a fun experiment. Maybe I could put some logs around it like a raised garden bed to help with erosion a little too.