I'd seen a few other ribbed models for a planter and the underside of the transition was a little steep and required supports and sometimes, 'finishing' work.

I decided to design something simple and easy to print as well as scale. I've printed this at 100%, 200%, and 300% with 0 issues and printed them quite fast with random Z seam so you can see the little dots in the images however it would be pretty simple to clean that up or have the seam only in one orientation. 

This would be pretty easy to reduce or add ribs or possibly add rain holes as well (current model has no drain holes), so if there's any interest I can adjust and submit modified versions as well.