I have an old outdoor garden bench that I bought from Ikea and I am considering converting into a raised garden bed. We once painted this garden bench many years back.
So my concern here is that there would be a risk of toxicity leaching from the wood into the plants?
Ikea seems to use Acacia these days, and I find it hard to imagine that anything but a hard wood would be used for outdoor furniture.
Lead based paints haven't been available in the USA since 1978 so that doesn't seem to be an issue either.
I'd still be inclined to line the wood with plastic as it might stop the wood rotting faster from being in constant contact with wet soil.
I don't know that it will be possible to provide any absolute answer. There are lots of remote possibilities and unknowns. The main concern is heavy metals. If the wood was pressure-treated before it was painted, metals are in the wood now and can leach out. Putting pressure treated wood in soil is a good way to poison the soil.
If you feel quite sure the wood was raw when you painted it, there is much less concern. Paint can - will, rather - flake off over time and end up in your soil. Unless the paint is very old and contains lead, however, the paint itself is unlikely to be toxic. Latex paint, the most common now, is more like bits of plastic that end up breaking up in the soil - bit of a mess, difficult to remove since they break so easily, not very harmful either. In the end you're going to have to decide how to hedge your bets.
