I know that a greenhouse is not air right so I imagine it breathes somewhat and exchanges gas with the outside. However, I also assume that it’s going to use up the co2 in it for plant growth. How does it not run out? I think you could vent it, but then wouldn’t that cool it off and thus defeat the purpose of a greenhouse? All my web searches either give climate change facts or co2 supplementation by farmers.
Plants don’t actually use up all that much CO2. An entire greenhouse worth of plants wouldn’t even consume as much CO2 as your body produces. Most oxygen produced on earth and CO2 consumed is done by algae. Land plants like trees can sequester more CO2 because they grow larger and use it to build their bodies but they do so slowly over the course of years.
So I guess plants don’t suffocate in greenhouses for the same reason that you wouldn’t if you sat around in a greenhouse. There is enough air infiltration through cracks and gaps in the walls that sufficient air gets exchanged to keep it breathable.
jeena@piefed.jeena.net 10 hours ago
I guess same as you get enough oxygen at home even if you don’t open the doors and windows at all.
untorquer@lemmy.world 9 hours ago
It’s called diffusion. Unless the greenhouse is hermetically sealed, and the rate of consumption does not exceed the rate of diffusion, the ratio of CO2 will be similar to that outside.
A simple vent will be enough if not just small gaps in the structure.
ryathal@sh.itjust.works 8 hours ago
Also, most green houses have fans that can help circulate air in from the exterior.