Visit almost any garden center and you will see attractive terra cotta saucers that are the same brownish-orange shade inside and out. Won’t they look lovely with matching terra cotta pots on your antique Louis XIV side table? But oops! Did you know that these saucers actually leak? Terra cotta is porous, so water will slowly flow through it, leaving a charming stain on your furniture. But wait a minute! Didn’t you buy a saucer precisely to protect your furniture from water damage? What was it those Romans used to say? Caveat emptor or something like that?
Ideally, if you want a terra cotta saucer, you should choose one that is glazed inside and therefore waterproof… generally sold by the same garden center that sold the leaky ones. Or buy a plastic saucer. Or place the offending saucer on a sheet of plastic, rubber or other waterproof material. Or if you’re feeling particularly energetic, you can paint the inside of the leaky saucer with a good waterproof varnish or paint (boat varnish, for example). Just don’t use an unglazed terra cotta saucer for your plants.
And I have a suggestion for garden centers: if you have this essentially useless product in stock, why not at least be honest with your customers? Add a label saying “This product is not designed for use with living plants.” A store that did that would get my business!