But increased food supply and better biomass doesn't come without its drawbacks. The effects of nanotubes on the environment aren't very well documented. Specifically, the way they might move through the food chain could pose problems down the road. Some single-walled nanotubes are toxic to some insects; testing on mice has found multi-layer nanotubes (like the kind used in the study) have carcinogenic effects similar to those of asbestos. Suffice it to say, the golden age of carbon nanotube farming isn't upon us just yet, but the potential is there, and not just for bigger tomatoes.