I don't know if it's because of all the rain we've had this year, or if indeed this technique of planting strawberry jars is genius. All I can say is that it works wonderfully well. I got the idea from "Container Gardening" that publishes the "Fine Gardening" magazine. It's really neat that they have a video to show you how.
It may be too late to do this now, but you can think about it for next year's herbs. I'm using their site to figure out how to freeze all the produce.
I used a black pvc pipe that I found at Home Depot, that also had a cap to plug up the bottom. Corks, in the correct dimensions, for some reason are difficult to find here.