Similar to the idea of hollowing out a tree stump, there are also plants that will grow really well in shallow rocks. You might already have a few rocks that are hollow enough t(Diy Garden Rocks)
Project: adorable rock cat for the garden! But Dog instead of Cat!
I posted another way" how to propagate roses" , had no idea that you could do it this way. How to Propagate Roses Using Potatoes Cool idea
What a great idea - i get these egg trays all the time, now i can use them to plant radishes, carrots or lettuce!