CO2 Levels in Greenhouses

Rather foolishly I treated myself to a netatmo weather station for my Birthday, and put it in the greenhouse to monitor the temperature. It works rather well, with a handy web app to track the temps on a 5 min basis.

Its also got a CO2 monitor, which has got me confused - my understanding of plants & CO2 is that they take it in during the day & give it out at night - but the monitor doesnt appear to show that at all:

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CO2 levels appear to be linked to temperature - can that be right or is it just returning duff values ?

Interestingly the new greenhouse has a sensor too but as yet no plants - and shows the same sort of trend:

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Whats giving off the CO2 ? is the the wall (both greenhouses are lean-too types fixed to a breezeblock wall) or the slabs / gravel, or something else ?

 

That's interesting Nick

Could be soil microbes.

 

Just for testing, could you not put it elsewhere, say in your lounge and see if it has the same trend ?

 

Very interesting Nick. I would agree with Dave - I would try it in the house and/or outside.

I had a quick Google and came acoss this site. http://co2.utah.edu/co2tutorial.php?site=7&id=1
It would appear that CO2 levels do change during the day with a minimum at midday - though yours seem to show a maximum at midday.

Its late now, so I haven't read all through this site - but it might help - or might not.

 

Does CO2 expand when heated which may increase the reading?

 

I think all gases expand when heated - but they all expand by the same amount. So I wouldn't think relative CO2 levels would change. Unlike humidity, where hot air can hold a much greater amount of moisture than cold air. Thus when the temperature rises, if the absolute amount of moisture in the air stays the same, the % relative humidity fall - ie the level relative to the maximum carrying capacity of the air.

 

Thanks for all the feedback - I will bring the sensor into the house next time Im out there & see what happens.

All this talk of CO2 levels has got me interested in seeing if theres an easy way to up the levels for the plants - so Ive just purchased one of these to see if it makes a difference - will let you know !

 

What weight are those Co2 bags? Would it be cheaper to get some 69p/Kg sugar from Poundstretcher, some Turbo yeast to ferment it out and get nearly 50% CO2 by weight from the sugar + a useful bi-product?

 

!! I cant believe I didnt think of that !!

I will definitely do the next round of turbo cider in the greenhouse - cracking idea!

 

Pop the alcohol in your Mower afterwards? Maybe enter the fastest-mower competition in your local fete?