I'm making a very large outdoor plant stand to house my houseplants on my deck for the summers. Rather like a multi-shelf baker's rack in appearance.
If the wood is left UNfinished, it will get stained from the constant water, spilled soil, etc. I'll be watering with the hose.

I'm mostly familiar with oil based indoor stains and varnishes from woodworking projects. Stains that soak in to the wood. Apply, wipe, let dry, reapply if needed. Top coated with oil based poly or other varnishes.
But I'm assuming that outdoor projects need something different. We were not able to find the right lumber in preserved wood. So we had to buy ordinary pine lumber; a nicer grade.

Ideally, if I can find the right product, I'd stain this plant rack dark to medium grey to coordinate with our light grey aluminum siding, or a medium brown. (Some color that won't show spilled soil or water marks). Then some top coat to seal the wood, non-shiny. Satin or matte. Unless there is some all-in-one product that works.

So what stain or finish will actually protect lumber used outdoors? Or use Thompson water seal or a similar product on top of the stain? Can it be used that way?

Someone on a DIY site suggested a powder you mix with water, Eco wood preserver. But reviews I read say it continues to leach out every time it gets wet, and will stain the deck. That would bother me, so I'm steering away from that now.

I am not a woodworker, just someone who makes a lot of home improvement projects and refinishes furniture, and I don’t have access to anything specialty. I can’t spray a finish; it will have to be applied with brush or roller.

So I'd very much appreciate your advice. Thanks!