Green roofs have become such a hot topic in the conversation about green building and sustainable design, that at a recent conference on the subject, there was a panel asking, "What's the next green roof?" As an indication of green roofing's trend achievements, there are now a few products emerging which allow every day consumers to install these heat island-diminishing, storm runoff-mitigating, urban aesthetic-improving grassy rooftop carpets.

Toyota, whose non-automotive division has introduced such surprisingly green-minded products as a flowering shrub that remediates air pollution, is manufacturing a product called TM9 turf mat under a subsidiary called Toyota Roof Garden. According to sci-fi reality blog, Technovelgy:

Individual mats are twenty inches square, and about two inches thick. The mats are planted with a special brand of Korean velvet grass - it only needs to be cut once per year. The mats are irrigation system-ready; water can flow through tubes to channels in the mats, providing moisture to roots.

There's no information in English about the material used to create the structural base of the tile, which appears to be plastic or rubber. Apparently, though, the low-maintenance nature of the selected grass type, as well as a design that allows efficient rain water capture, means that a grass roof made from TM9 tiles might be a good answer for urbanites who want the environmental, aesthetic, and home insulation benefits of a green roof without a lot of work. The fact that this is a viable consumer product these days does a lot to show how far the idea has progressed into mainstream culture. It really does beg the question: if green roofs are now quotidian, what's next?