>>1310776So long as you don't nail into something, it isn't tearing up the roof/siding, and everything is safe from falling, I don't see why you'd not be allowed.
>It is very unusual for a 23 yo to want a garden at all.I think that might be a culture thing where you are. Where I am, people take classes in high school for agriculture, (Future Farmers of America) and summer vacation is working on local farms making contacts, baling hay, planting/harvesting crops, and mucking stalls.
