Plants need CO2 to grow..
It is well established that as CO2 in the atmosphere increases, the rate of photosynthesis increases. This is known as the CO2 fertilisation effect.
https://en.m.wikipedia.org/wiki/CO2_fertilization_effect
From a quarter to half of Earth’s vegetated lands has shown significant greening over the last 35 years largely due to rising levels of atmospheric carbon dioxide.[3]
One related trend may be what has been termed “Arctic greening”. Scientists have been finding, that as northern portions of the planet warm up even as total atmospheric carbon dioxide increases, there’s been an increase in plant growth in these regions.[4]
Studies led by Trevor Keenan from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) show that, from 2002 to 2014, plants appear to have gone into overdrive, starting to pull more carbon dioxide out of the air than they have done before. The result was that the rate at which carbon dioxide accumulates in the atmosphere did not increase during this time period, although previously, it had grown considerably in concert with growing greenhouse gas emissions.[5]
I was in a cab from the airport in Whitehorse, Yukon Territory, to my hotel and was talking with the driver. He had an indoor fresh vegetable grow operation attached to his house. He claimed he made good $$ providing fresh tomatoes and other stuff to local Whitehorse restaurants during the long, very severe, winter months.
He told me that his grow results increased dramatically after he installed an exhaust system from his house to the grow building. He lived with his wife, two kids and a couple of dogs. He maintained that the increase in CO2 made all the difference.
I remain a bit skeptical when hearing anecdotal stories, but this one sounded believable.