CO2 experts... what say you?

In a sealed 20x30, in week 6. CO2 burner had been introduced at 1200 ppm at the flip. Whats your opinion on dialing down ppm's and temps towards the end of flower?

There are so many opinions about that.
Some say more and more and keep it steady till the end.
Others say dialing down.
A well known grower from where I come from never exceeded 1000 ppm.
Commercial greenhouse growers don't go past 850 or so, because they say more does not make sense.
I think it is also strain dependent.

Keesje said:

There are so many opinions about that.
Some say more and more and keep it steady till the end.
Others say dialing down.
A well known grower from where I come from never exceeded 1000 ppm.
Commercial greenhouse growers don't go past 850 or so, because they say more does not make sense.
I think it is also strain dependent.

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I hear ya. I’ve read so many different options. I suppose I’ll just start dropping every few days (CO2 and temps).

This is from a report of Wageningen University, the world's leading agricultural university.



Translation:
Relatieve productie = relative production
CO2 gehalte = level of CO2
lichte dag = light day
gemiddelde dag = average day
donkere dag = dark day

What you see is that the production flattens in the region of 800 - 1200. Not significantly more production.
And you can also see that the production is higher on light days. So more light, more production.

They did many test on what is the optimal level of CO2 for certain plants.
For cut chrysanthemums for example they found out that at 1200 µmol (the light in the month august) it is 800 ppm.
For florist chrystanthemums it is slightly higher: 900 ppm.
For tomato it is just 700 ppm.

If you got the light I mean 50w per sq/ft I keep it up. As you can see with your chart if not enough light high Co2 levels go wasted. That is the cut off point for benefits with it.

Jdubb203 said:

If you got the light I mean 50w per sq/ft I keep it up. As you can see with your chart if not enough light high Co2 levels go wasted. That is the cut off point for benefits with it.

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That's why I say I may drop co2 levels, temps, and raise lights in that trifecta over the next 3 weeks to the finish. Who knows.. we'll see how this turns out.

Anyone know a decent co2 requirements calculator, a basic one?

I doubt it that such a calculator does exist.
In professional greenhouses where they add CO2 grow for example tomatoes in different stages.
So very young till ready to harvest.
They all get the same amount of CO2.

I came across a few.

2com said:

I came across a few.

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really?
Do you have a link?

Edit: I think I misunderstood you.
You probably mean a calculator that tells you how much bottled CO2 for example you need for a room of a certain cubic feet if you want to maintain 800 ppm?

Keesje said:

really?
Do you have a link?

Edit: I think I misunderstood you.
You probably mean a calculator that tells you how much bottled CO2 for example you need for a room of a certain cubic feet if you want to maintain 800 ppm?

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Yea, that type of thing. Or just how much flow, to hit a certain level, in a given volume, type of thing. Which I understand leaves several variables not addressed. For example the amount of plants/rate of use of the co2, etc.