A man who sealed himself in an airtight greenhouse with the intention of surviving on plant-produced oxygen for three days has been forced to quit the experiment early.

YouTuber and self-described "whimsical scientist" Kurtis Baute lasted just over 14 hours in a 10x10 cube he built in the Comox Valley.

Baute sealed himself in the cube to spread a message of awareness about climate change.

He had just enough space for a few dozen plants, a hammock, a chair and a table set up with equipment that monitored oxygen and carbon dioxide levels in the mini-greenhouse.

Baute invited his online audience to follow along using the hashtag #KurtisInAJar on Twitter, where he detailed oxygen loss in the cube Wednesday morning.

Just after noon, Baute tweeted that the greenhouse was cloudy from carbon dioxide – and the plants weren't putting out oxygen fast enough.

"CO2 is building up. At this rate I'll be out within a couple hours," he said.

Half an hour later, he noted that the carbon dioxide from his breath was slowly building up to levels that would force him to abort the project. Levels reached 10,000 parts per million, which is the maximum reading Baute's equipment could sense. 

An hour after that he said he was feeling sluggish, and at around 2:15 p.m., Baute tweeted a photo of him outside the cube.

He assured concerned followers that he was safe, and despite dropping out early, that he felt the experiment was a success after seeing engagement on Twitter.

"Thanks to everyone for your support. Now is just the beginning – it's time to change our lifestyles!" he wrote.

Baute said he documented the entire ordeal and will be putting a video out on his YouTube channel as soon as he can.