I mean, I want to make some plant shelves. any ideas?
Thanks,
Srilu

Pallets would work fine for it. The cinderblocks would, too, when you can keep the "tabletop" supported. The plywood might warp.

Though, personally, I wouldn't use whole pallets. Sure, they're a big table that can hold quite a few pots, but you might run into issues when working with the plants. If you were to halve them, you could, for example, go around the perimiter of your patio, and either have a center larger table that you can walk around, or have little rows of shelves coming from the perimiter. It'd give the plants more space, and you more working space. Plus, it's easier to see insect problems, and seperate them when it's not all on 2-3 huge platforms.

By halving, I mean cutting the 3 support bars that hold the top and feet of the pallet together. 3 small cuts to make 2 parts.

Thank you for the reply. Cutting the pallets and arranging along the wall is a great idea. But I don't have tools to cut the pallets and I have never done any kind of wood work before. I also like to idea of using table tops. I got some cinder blocks for free from craigslist. I will buy table tops or get some wooden shelves from lumber store. Once again, thank you for the great ideas.

Wire racks shelves are worth a look.

I think wire racks might be good too because they'd let in more light to the lower shlves (depending on where you'd locate them).
Maybe your goodwill or your freecycle might be a source?

I,too, have many container plants which I would like to arrange in my small patio. I have looked at shelves, but I think that would be too expensive.
My patio is open, so it gets rain. Could wall building blocks work, or would they be costly as well?