Girl, we get around don't we lol. My mom has used a wheelchair for 25 years so as for doors, especially a greenhouse I say the wider the better. Nothing worse than smashing your fingers. Also even if yoy never need a chair, the time might come, like now, when you might want to pull one of those garden wagons into the GH. If you go th the ADA website you can find all accomdation guidelines. I would think that a bench would be comparable to a lavatory in a washroom. My Mom has a potting bench with a lip so she can scoop dirt in a pot with one hand. She holds on with the other. At one side is a screen so she can just push the dirt into a container underneath and the screen sifts out the debri so the dirt can be reused. A watering system is installed so all she has to do is turn on a spigot. Hope this helps.

Loretta

Here is a link that might be useful: ADA

Lol Thanks loretta. Small world, cyberspace. I couldn't wait for an answer, and built too high, accd'ing to ada standards, but did leave about 4' between everything for chair or garden carts, and the doors will work for both too. I also made a big lazy susan out of an old patio table that would keep me from haveing to take as many steps as I would without it, but it's way to high for easy chair use. I'll just have to stay upright in my old age, or make changes down the road. But I might yet be able to incorporate your Mom's style of potting bench. Thanks.

Boy, that potting bench sounds just great! Where did you get the plans for it?? I'd love a copy...is it something I can order?