This San Francisco roof garden was built with the Woolly Meadow.
We haven’t tested Woolly Pockets (or even seen one of these in person yet), but they seem to fill a great roof gardening niche: they’re pretty affordable ($247, hey… one plastic pot at Home Depot is twenty bucks!), lined to protect the roof, and fold-able for winter storage. The containers is light, but be sure your roof can support the weight of soil + plants + water + the Woolly.
Starting out with this $45 Woolly Patch might be the way to go … and I love this sedum.
Images: Woolly Pocket Garden Company, used with permission