Light and augmented CO2

I recently went from using Exhale bags to a tank and regulator. In this particular grow, no bag has been in the tent at all. With the tank, am able to dial it in accurately. Running at about 1000ppm. Shuts off when lights go out. I recently screwed up and believe a lesson learned. However, I’d appreciate some confirmation or correction of my conclusion. Once I reached desired CO2 level, I immediately consulted charts and pushed par on a couple vegging plants from about 600PAR (where they were really happy) and within two days pushed up to something near 900PAR. By end of second day, plants showed first signs of stress; leaves turning away initially. I immediately backed the light energy back down closer to where I began. In the next 5 days I’ve seen a good amount of bleaching. They got shocked pretty good. My assumption is that while plants may be able to process more light with CO2, they can’t do it without adjusting first. Kind of like a Minnesotan going to Baja in January. Going to take awhile! So my question is whether this is correct, and if it is, does anybody have any charts/links/experience about ramping up light at a rate photos stay happy? Does it make a difference if the CO2 is added throughout a plant’s lifetime or later in the game?

High levels of lighting are required for a plant to use excess CO2. By high I mean 1,200 PPFD plus.

I’m not sure that lighting is the cause of the issue you mention. I always run my plants at 1,100 PPFD (without CO2) and have never had a plant try to tell me that it is too much.

A PPFD of 900 is pretty common. The minimum recommended during flowering is 800 PPFD. 900 is not enough lighting for CO2 to make a difference.

Do you have pictures? What are you using for lighting?

I go from 400 (Seedling) to 800 (veg) to 1,100 (flowering) without regard to making incremental changes.

The ratio of light, air, and water is completely different than all the other aspects of keeping a plant healthy. Just because you’re supplying co² doesn’t necessarily mean your plants will safely be able to process more light. The additional co² just means that your plants could do more work provided everything else is in check, not that they WILL do more work because the co² is there. The process will still rely on light intensity, water and nutrient availability, leaf surface temperature, vapor pressure deficit, and probably several other factors.

It’s reasonable to believe a large rapid increase in light intensity could be rejected by your plants. Sometimes certain genetics are more sensitive to light intensity even after slow increases. But from a general sense, most people will recommend making light intensity increases gradual over a period of time.

Here’s photos. These are 2 Gorilla Glue in a 4x4. Maybe 7 weeks old. Medium is top 2/3 Happy Frog. Bottom 1/3 is Build a Soil. Not adding anything beyond a bit of cal mag in water. Water is RO and pH kept between 6.25 and 6.5. Light is an HLG Scorpion Diablo which is currently running at 72%. Distance 17" produces a PAR at canopy of about 750. There could be a tiny bit of nute burn which existed prior to cranking the lights but just chalked that up to roots getting into the hotter soil in bottom of pot. Did not impact plant’s vigor. Have kept the environment stable as shown. Only variable I can come up with is adding the CO2 and cranking the light
I would add that I had 4 early flower autos in my other tent which got the same treatment. Three of the four did not have an adverse reaction. I figured maybe that was because they were more mature.


ghts.