I have a motley collection of containers – some of them quite old. In the beginning I used clay pots but that gets expensive and the downside to clay is the pots dry out very quickly (it’s windy on my back deck and when the sun shines it gets rather hot). So I started adding clay-looking plastic in various shapes and sizes.
I have some small pots but more and more I try to keep the number of small pots to a minimum and use the largest, inexpensive pots I can find. They need drainage holes – so if the container doesn’t have any I drill many holes with my electric drill using the largest bit I have. And because my pots are sitting on a wooden (pressure treated) deck, each pot sits on an inverted saucer so that the water can slowly drain from the pots but not saturate the wooden decking. (I do have a few saucers on wheels – I drilled holes in them because otherwise they fill with water when it rains and drown the roots in the pots if I don’t get around to emptying them pronto.)
I start a new pot with a layer of styrofoam peanuts for drainage (in the beginning I used gravel – but that can make the largest pots practically unmovable). Next I add bags of black earth and top the pot up with outdoor potting mix containing fertilizer. About a month into the season I add some time release fertilizer (usually one that encourages flower formation).
Each spring, I clear off the remains of last year’s growth, trying not to disturb whatever might be growing – I don’t clear until I see signs of the perennials returning and until it’s warm enough to be out on the back deck. I loosen the soil around the emerging plants and dig in a bit of time release fertilizer. The pots that held annuals, I clear off completely, dig and turn the soil, adding some fertilizer. I don’t need to water existing pots – they’re soaked pretty thoroughly having been buried in snow all winter. New pots get wet down before I do any planting.
Small pots also get new potting mix each season to which I add water retaining granules. This gel swells in the presence of water and slowly releases the moisture as the soil around the cubes dries out. This keeps the soil more evenly moist and prevents the pots drying out too quickly.
Anything can serve as a container so long as you can create draining holes: barrels, wheelbarrows, storage containers, crates, tires, boots… anything you can think of. I mostly stick to “pots”.