Yellow/brown spots leading to yellowed leaves & curling up.

[yerboyblue]

Interesting.... The symptoms you describe sound strikingly similar. 2+ weeks into flower and the spots start showing.

I sheathed the flower area with OSB, sealed with Great Stuff foam, painted with Kilz primer and lined the walls with mylar bubble wrap.

I have never heard of anyone having issue with off-gassing associated with these common products. Also, the space was finished about a year ago.

Things that make you go Hmmmm..

Do some research into the Kilz primer, wouldn't hurt to spend an hour looking into it. The ingredient that was killing me was dibutyl phthalate, which is a VERY common ingredient found in latex paint, it is a polymer that helps with coverage. I don't know if the Kilz has it, but it is common in exterior latex and many other latex paints, also painters caulk. I figure if the primer or paint isn't specifically labeled 'low VOC' (volatile compounds) there is a good chance stuff can off gas. I also chased this problem for about 7 months as a nutrient and pH issue before figuring it out, it can offgas for awhile. It would start as a small cal and mag deficiency and progress into more severe deficiency of those, plus others. I noticed when I cranked the intake and exhaust on full blast, everything perked up because the nasty stuff was being cleared out faster than it could damage, I suspect people that don't have issues with the paint have good ventilation. The other stuff used in the build should be fine.

 

[JamesFarmer]

Do some research into the Kilz primer, wouldn't hurt to spend an hour looking into it. The ingredient that was killing me was dibutyl phthalate, which is a VERY common ingredient found in latex paint, it is a polymer that helps with coverage. I don't know if the Kilz has it, but it is common in exterior latex and many other latex paints, also painters caulk. I figure if the primer or paint isn't specifically labeled 'low VOC' (volatile compounds) there is a good chance stuff can off gas. I also chased this problem for about 7 months as a nutrient and pH issue before figuring it out, it can offgas for awhile. It would start as a small cal and mag deficiency and progress into more severe deficiency of those, plus others. I noticed when I cranked the intake and exhaust on full blast, everything perked up because the nasty stuff was being cleared out faster than it could damage, I suspect people that don't have issues with the paint have good ventilation. The other stuff used in the build should be fine.

I did some checking and could not find any reference to dibutyl phthalate in Kilz. I do see Kilz Original referred to as "low VOC". Unfortunately I don't remember if that is exactly the product I used.

I am seeing improvement after adding KoolBloom and CalMag. I am going to tweak my ventilation as well. I just have to be cautious with temps. We are in the single digits outside at night. Teens during the day I left the door outside open for 2-3 minutes yesterday and the indoor temp dropped from 77F to 59F.