Most all my autos stay small none can compare to a 90 day vegged photo hell even a 60 day for that matter.
Well now you're comparing apples to oranges.
You could say a 60day veg vs 90day veg on a photo will give diff results... of coarse... It's a different amount of time vegging. If an auto say veg for 60 days(of coarse not) vs photo vegged 60 days what would make the results differ other than genetics....? I've seen autos that just turned into giant pop cans of buds that would have out produced most photos I've grown with the same amount of veg time. If you can veg a plant well, in a few weeks you can have a pretty decent base to flower off. Some autos take longer to flower too so there's that. Most people make mistakes and that just costs yeild and size with autos.
I like them, I grow them but I just find there to be alot of variation in autos where some plants will be great and others not so much. I'd never grow autos anywhere other than the mom room/veg room and or outside.
