The problem is that the office was never meant to act as a greenhouse. The floor is easily damaged by water. When I first started growing plants in there, I put down a sheet of plastic underneath the shelves. That helped, but sometimes water got underneath it, then sat and damaged the floor.
Last year, my husband made us a new bed with drawers in the bottom of it. We had no more need for the underbed boxes we used for extra blankets, and they were relegated to the shed, where they sat empty.
Until I had a brilliant idea.
Those underbed boxes were the perfect size for my plant shelves. They’re fully waterproof, so water no longer gets even close to the floor. And when the shelves overflow, I can use a box directly on the floor for more plants.
And the cat approves of them too—a box in a sunbeam!