> though most plants pretty quickly decay and release their CO2 back into the atmosphere, with the exception perhaps of some woods There are ways to keep a fai

> though most plants pretty quickly decay and release their CO2 back into the atmosphere, with the exception perhaps of some woods There are ways to keep a fair amount of the carbon. Old plant material should be composted and thus recycled. An alternative is to create biochar and amend soil with it, which has potential to sequester the carbon for millennia. Some farms use a no-till method to add the organic matter into the soil. Basically, if the commercial greenhouses do anything with their plant waste apart from putting it in a landfill then it's back in the growth cycle of some other plant.