We recently moved from the remote north woods of Wisconsin where people create great lakeside campfires by digging large fire pits into the ground and lining them with large rocks. We now live in a residential neighborhood in the Central Valley of California. Here, campfires are confined to pre-built pits or structures. People build only small controlled fires to minimize the risk of sparks blowing into neighboring combustibles when the fire is left unattended. These smaller campfires are also easy to extinguish, with less risk of embers continuing to burn.
Even with these restrictions, our family still loves to sit outside around an evening fire in the backyard. But we didn’t want to spend a small fortune on a pre-manufactured patio fire pit or a contractor built unit. We were also not sure where we might permanently want the pit located. So we needed something we could take down and move to a different spot without a lot of trouble or expense.
Fortunately, while cruising the aisles of Home Depot recently, we saw concrete tree rings (circles that are used for flower beds at the base of a tree) on sale for $2 a section. We borrowed a tape measure and quickly determined that the rings might make a dandy low cost fire pit that would incorporate a small Weber grill (which we already owned) as an inner firepot, allowing a very controlled burn and positive air shut-off to extinguish the fire when we were ready to call it a night.
Total cost: $50-$80 depending on your taste in stones.
Find a nice level area of your yard or create a level circle approximately 3 feet in diameter. It's not absolutely necessary but we sprayed our pit area with weed and grass killer to make a bare spot. You will notice the ring of browned grass surrounding the pit in the final photos. This is due to the weed killer and not the result of heat from the fire. We also placed a layer of weed barrier cloth under the pit to prevent grass/weed from growing up into the pit. The tree rings will be more stable on bare earth than on grass, particularly if you have Bermuda grass like we do. Also, you should have no problem if you want to place your pit on top of a concrete or brick patio.
The trick to turning tree rings into a decent looking fire pit is to make the ring two sections tall by turning the fluted top sections upside down so they interlock with the fluted bottom sections. The first photo shows what the 14" tree ring sections look like when you buy them from the store and the second photo shows them stacked. They don’t fit perfectly but the small air gaps look sort of decorative in my estimation and are barely noticeable once the unit is being used.