The grass roots aren’t the issue, Without seeing a 360° view, we don’t know how close the nearest tree is. Some tree roots grow quite a ways to the sides, and can be hiding just under the soil.
For my last house, I dug about 6 inches down, and put a layer of gravel to fill up to the ground level. Pea gravel on bottom 3 inches and larger inch or so gravel on top. Then spaced the bottom ring so there was about 1.5-2in of space for air to flow in.
I also tried covering the inside of the stones I used with leftover high temp cement from making a blacksmithing forge, but it didn’t adhere well to the stone and flaked off after a couple uses. it would probably do better on concrete retaining wall slabs.
I built it to last, for sure. But I wouldn’t say I over-built it.
This kind of ring in OPs pic is probably fine for their purposes, but it’s always good to be aware of things like root fires.
The grass roots aren’t the issue, Without seeing a 360° view, we don’t know how close the nearest tree is. Some tree roots grow quite a ways to the sides, and can be hiding just under the soil.
For my last house, I dug about 6 inches down, and put a layer of gravel to fill up to the ground level. Pea gravel on bottom 3 inches and larger inch or so gravel on top. Then spaced the bottom ring so there was about 1.5-2in of space for air to flow in.
I also tried covering the inside of the stones I used with leftover high temp cement from making a blacksmithing forge, but it didn’t adhere well to the stone and flaked off after a couple uses. it would probably do better on concrete retaining wall slabs.
I built it to last, for sure. But I wouldn’t say I over-built it.
This kind of ring in OPs pic is probably fine for their purposes, but it’s always good to be aware of things like root fires.