And it does seem like a horrible waste in the name of convenience, to use these self-contained, filtered coffee brewers for one-time only. Especially when they have such promising potential for reuse as an effective seed starter.
I did not know about the inside filter until I peeled the lid off a used cup, out of curiosity.
I dumped out about a tablespoon of coffee grounds into the garbage, and replaced it with potting soil.
The same design elements that make k-cups good at brewing coffee make it great for starting seedlings, since the soil gets good drainage from the filter and bottom-hole.
I would love to see a coffee company start to make these out of heat-resistant bioplastic so that that gardeners could just plant the whole k-cup into the ground.