Greetings

I will soon be building some raised garden beds from 10mm Jarrah. Although
this is structurally sound enough AFAIK I'm concerned that being relatively
thin it will rot/degrade somewhat faster than thicker material.

My plan, if I can find suitable material, is to paint the inside of the
framework and varnish the outside.

Does anyone have any ideas for the paint and varnish?

TIA
Ivan.