Leveling a Bed That Tilted After a Wet Spring
I was filling the watering can from the spigot near the fourth bed in July when I noticed water pooling more on one side of it than the other after I had watered, sitting there instead of soaking in evenly. I stepped back and looked at the whole bed from the path, and it was leaning, low on the corner nearest the fence, high on the corner nearest the lawn, enough that a marble would have rolled from one end to the other if I had set one on top of the soil. I actually went and grabbed a marble from a drawer inside just to check, and it rolled the full length of the bed without any help at all.
What a wet season does underground
We had a stretch of heavier rain than usual that spring, week after week of it, and the ground under that corner of the bed had clearly settled during all of it. The bed sits on packed soil, not a poured pad or anything solid, and repeated soaking and drying can shift that kind of ground more than people expect, especially in one corner where drainage off the nearby path happens to concentrate a bit more water than the rest of the yard. One side of the bed had simply sunk lower into softer ground while the other stayed put, and it had happened slowly enough over those weeks of rain that I had not noticed until the tilt was fairly obvious.
The shim that did not last
My first fix was quick and a little lazy, honestly. I found a flat piece of scrap wood, wedged it under the low corner to prop the bed back toward level, and figured that would hold. It worked for about two weeks. Then a good rain came through, softened the ground under that shim, and the whole thing sank right along with the corner it was supposed to be supporting. I went out one morning and the bed was leaning again, if anything slightly worse than before, because now there was a rotting scrap of wood buried under the corner as well, which was not going to help anything the next time it rained hard.
Doing it properly this time
I ended up emptying enough soil out of that end of the bed to take some weight off, which made it possible to actually lift the low corner using a pry bar and a block for leverage. Once it was up a couple inches, I dug out the soft soil underneath, down past where it had gotten saturated and mushy, and packed the hole with compacted gravel instead of dirt, tamping it down firmly in layers rather than dumping it in all at once. Gravel drains and compacts more predictably than the native soil in that spot, so it gave the corner something stable to rest on instead of the same soft ground that had caused the problem in the first place. It took longer than the shim had, closer to half a day once I counted the soil removal and the tamping, but it felt like an actual fix rather than a stopgap.
Checking the other corners while I was at it
With the low corner propped and exposed, I went ahead and checked underneath the other three corners of that same bed while I had the pry bar out and the tools already gathered, mostly because it seemed wasteful not to. Two of them were solid, packed as firmly as the day we built the bed. The third had a small amount of give as well, nowhere near as bad as the corner that had actually sunk, but enough that I decided to pack a little gravel under it too rather than wait for it to become its own separate project a year from now. It added maybe half an hour to an afternoon that was already going to be a long one, and it meant I only had to pull out the level and the pry bar once instead of coming back to the same bed twice in one summer.
Getting it level and keeping it that way
I lowered the bed back down onto the packed gravel and checked it with a level across both directions, adjusting the gravel pack under the corner in small amounts until the bubble sat centered rather than eyeballing it the way I did with the wood shim. Once it read level I refilled the soil I had taken out, watered it in over a few days rather than all at once, and kept an eye on that corner through the next couple of rainy stretches. It has held steady since, no sinking, no new lean, and the marble test stays put wherever I set it down now.
What I would change about how we built it
Looking back, we set that bed directly on the existing ground the same way we did the other three, without doing much to prepare the base first, and it happened to land in the one spot in the yard where water tends to collect a little more than elsewhere. If I were starting that bed over, I would dig out and pack a gravel base under the whole footprint before ever setting the frame down, the same fix I ended up doing under just one corner after the fact. It is more work up front, but it would have saved me a soggy morning with a pry bar and a very damp block of wood, not to mention the two wasted weeks I spent trusting a shim that was never going to hold.
