I grow quite a few annuals that bloom best if they are routinely dead-headed of spent flowers and seed capsules. Johnny Jump Ups, one of my favorites, benefit from this type of grooming. I also use these small violas in my pressed flowercraft. To make access easy for pressing and dead-heading I like to be able to move the container they are growing in to a higher level. The dollar store oil pan they are planted in makes this easy, and yes, the pans are only a dollar. You can find them in the automotive section of most dollar stores.
I used several of these last year for my annuals. All I did to prep them was bang a drainage hole in the bottom with a hammer and screwdriver. (See below for my drainage hole trick) I found the entire bottom cracked and this made no difference at all. The bottom was hidden, and the wide cracks kept the soil well drained. Plants that don’t have a tap root do very well in these oil pans. Four to six annuals fill the pan and grow well for most of the summer.
Drainage bang out trick – To bang holes in plastic containers I place the bottom flush against the lawn. The grass gives the screwdriver/ice pick a stable area to enter after it cleaves through the plastic. This is an easy method that only takes a minute or two. The bottom doesn’t look that nice, but hey, who sees it anyway? Only you, me, and the earthworms will know the difference, and I”m not telling! If the hole/crack seems too large cover the area with a coffee filter before adding soil.