here's bunch of ideas/pictures https://www.google.com/search?q=DIY+high+chair+turned+planter&rlz=1C1CHBF_enUS750US750&oq=DIY+high+chair+turned+planter&aqs=chrome..69i57.9907j0j7&sourceid=chrome&ie=UTF-8 this is cute https://www.youtube.com/watch?v=XpCAA9V5-BE more https://www.youtube.com/watch?v=6XtDKh3JlYE
You can use the seat to hold the pot, just cut out for it. I would recommend painting with an exterior paint that is very durable.
Hi Ethna, it would look stunning as a plant stand. Here are a few ideas that might inspire you - https://balconygardenweb.com/chair-planter-ideas/