What to do with garden tub that was painted by previous tenants?

You can scrape off all that is loose and peeling and spray, sand the rough spots and then paint with a metal paint such as Krylon or Tremclad.

What is the surface of the tub?

Whatever you do, make sure you get the landlord's permission.

Who paints a garden tub?

Scrape off the excess paint like someone previously suggested. Select an epoxy paint like people use to paint over indoor bath tubs. Are you using this for a fish pond or for a bird waterer? Make sure the paint type you chose is not toxic to the little critters...

If it is a porcelain tub try a mild striper or try spraying with "super clean" (purple color container) then use a 'magic eraser'.

Sounds like there may be 2 trains of thought here on what you meant by "garden tub" ---- indoor bath or outdoor planter?

It makes a difference!

I made this mistake, using a bronze metallic paint on top of porcelain. It does not hold up very well. The old tub's glaze had worn off in the bottom of the tub and I was trying to spruce up the look. When I finally decided to remove the paint, I used a green scrubbee and comet. It was already scratched and it looked better just clean, even unglazed on the bottom. I would not paint a tub again.

If you want to use this in your home, you could take it to an auto body shop and have them paint it. If this is just for "looks", I would use CitriStrip (non-toxic) and totally strip everything off for a clean surface to start with. You can use an appliance paint or similar to get a uniform finish. 😎