I sow everything at this time of year -- tomatoes, marigolds, petunias, herbs and many others. In fact, I did my first 13 containers today and have two of zinnias and one marigold. I've been doing this for a few years now, and though I've never done zinnias this way I'm sick of them not sprouting when I direct sow so I figured I'd try them this way. Marigolds do fine at this time of year, so why not zinnias. Nothing's going to come up until the temperature and the soil in the containers warm up anyway.

This isn't a way to get a headstart on the season. It's a way to utilize nature's own way, and free up space on the windowsills. :)

BTW, I've had the occasional dud container, but very occasional, and the one time I'm pretty sure it was the seed because I tried again in the mid-spring with the same seed and got nothing then as well.

Caryl