can you define what you mean when you say 'metal' raised beds ...

and why would metal burn anything ... at worst.. it might rust and add iron to the soil ... but i doubt that ...

and why are you raising the beds.. is there something wrong with your native soil ....

ken

"why would metal burn anything"

Because most metals conduct heat. And far more than any black nursery pot will. And there are all kinds of reasons folks might prefer to use a raised bed that has nothing to do with soil conditions.

Can you provide the dimensions? Is it a stock tank or just a raised bed kit? Depth would be a significant factor.

I am thinking of buying 4'x2'x2' metal raised bed kit.

That's quite small, not much more than a window box. If it catches the sun the soil could well get hot, especially at the sides. Can you show the bed you are thinking of? I'd also wonder if it's worth it at that size unless your native soil is very bad, you have physical limitations or you're gardening on concrete.

I am going to have this box sit on a paver patio. I have a wall next to the patio that looks very bare. The reason I am thinking of that size is that I don't want it to take up a lot of space on the patio

What if it is 6'x3'. Would that make it better for the perennials?

6x3 is better. The lilies won't care - it's the clematis that produce massive root systems that may encroach to the outside edge of the container and be vulnerable to excessive heat. If you can site the clems close enough to the back wall, you should be okay.

when visiting some garden show ages ago they had fancy, massiv metall planters like sculptures,

we were visiting in spring and all the tulips next to the outer wall looked dwarfed or stunted compared to the others. Wider would be benefical, I am quite sure.

Thank you all fornyour inputs! They have helped me tremendously in making a decision.

This is what I plan to do, will be planting some vegetables

Got cucumbers and cantaloupe on the right

Oops sorry for the duplicate photo and i can’t delete from the phone

This is now