NMoasis said: What's underneath that first little bed? If it's directly on soil, I agree that's you would do best with an organic like compost. What's in it so far?

I put plastic on the gravel, then the soil. All I had was fine perlite, hence wanting coarser stuff (keeping the thread on track, lol), but did add coir, spagnum and some compost, though I didn't have a lot of any of those, and had to spread it around the other containers. But the annuals I planted there did great, despite the soil issues.

I want to switch to perennials, but probably won't do that until fall. It has to be something that won't require a lot of depth. The other area is also shallow, but the salvia planted there does really well every year, so I may just do more salvia, which I love.

Any chance you can get in there and remove the gravel and plastic? Most perennial roots will eventually grow down into the soil, even if it's clay, then it isn't shallow. I'd just dump a couple of bags of something like raised bed mix or even topsoil with some compost amendments into that little bed. A raised bed set on bare soil acts differently than containers. You've got a few different scenarios going on there.

NMoasis said: Any chance you can get in there and remove the gravel and plastic? Most perennial roots will eventually grow down into the soil, even if it's clay, then it isn't shallow. I'd just dump a couple of bags of something like raised bed mix or even topsoil with some compost amendments into that little bed. A raised bed set on bare soil acts differently than containers. You've got a few different scenarios going on there.

The ground underneath my entire property is hard-packed and unbelievably rocky. It is impossible to make a dent in it. I loosened up and pried out as much soil and rock as I could (not much) before putting the plastic down.

Understandable when your plan was to cover it with gravel. Now that you're going to add soil and plant in it, the drainage and overall health of the bed will improve without the plastic. Can't you remove it just in that bed? It's your choice, I won't belabor it further. But I can give to advice re containers.