Which Pro-Mix exactly? HP? Organic Mix?
If it’s something other than HP or BX, I believe the other mixes are pre-fertilized with weeks/months worth of nutes, so I’m not sure about supplementing with GH.
I use HP and GH myself. HP has 7-10 days worth starter nutrients. Yours looks a little stunted at the moment so I’d be careful with extra nutrients at this point. I would expect it to be a little bigger and greener, even with a single proper nutrient dose by now. I also would not have fed this more than once by now.
Do you track your pH by any chance? Pro Mix is definitely pH sensitive and you want to be down around 6.2. If you’re in the 6.5-7 range you’re going to have problems. And do you also know anything about your water quality, ie ppm? If you fed multiple times this early and it’s still yellow-ish, I’d think it’s more of an absorption issue rather than under-feeding eg, due to an improper pH.
You also shouldn’t need to push past 50% of the “light“ chart until week 5 or so — again, assuming you’re in HP or BX. I feed heavy, but infrequently, ie, feed-water-water-water-feed. For example, in my current grow, I probably only fed 3 times in the first 4 weeks.
FWIW, I’m keeping a grow diary of my current Pro-Mix HP+GH grow here:
https://www.autoflower.org/threads/...135w-v2-quantum-board-leds.83802/post-2454310
