So this is what I do, definitely not the only viable method, but it nets me a pound+ per 4x4 reliably now. Here’s a past grow at transition and harvest:
Before anything is adjusted, I’d recommend looking more heavily into your seedling and veg stages. I am of the belief that if you aren’t at 100% coverage by the end of stretch, then you are missing out on yield… and nutes and light are the least of your worries. I try to have a cola in every single trellis square, sometimes more. I also aggressively train my plants such that they are all the same height before I flip to flower.
How many plants one has is irrelevant to weight, what matters most is floor coverage. I personally would ignore the data given about yield when buying seeds, that’s highly dependent on so many things. One giant plant vegged out to a 4x4 still produces the same amount as 6 little plants in the same space.
I’d also stay away from autos if you’re after yield unless you’re doing an aggressive SOG. With autos, you don’t have the luxury to veg for long, or perform very much topping, if at all. This is why autos by and large produce a lot less. Plus a single cola plant will net you next to nothing compared to one with multiple tops (indoors that is).
As far as light goes, I go about 10W per square foot in seedling / veg, 20W per square foot at transition to flower, 30W per square foot at week 3 flower, and 40W per square foot in late flower around week 5-6. Blasting the plants with a lot of light in veg does not make for bigger stronger plants. You will run out of useable light in flower, hurting yield.
For example, I use a Mars Hydro FCE6500 at 720W of total power. In a 4x4, I know I’ll need 640W by the end of flower, meaning my knob must be set at 22% (160W) all the way through end of veg, 44% (320W) at transition, 67% (480W) at Week 3 flower, and 89% (640W) at week 5-6 flower. Running the same grow under 640W from start to finish would be a noticeably worse grow. My lights always stay at the tippy top of the tent, without exception.
While par meters, PPFD, PPD, DLI etc and all that fun stuff is great and all, I am of the mindset that that shouldn’t even be a consideration until you’re totally dialed in and have all your other inputs perfected. This is why I don’t yet have a PAR meter or even bother using one. I still get shitty leaves from time to time so I obviously still have some dialing to do. But again, this is only one guys opinion.
My grow journal is below, running perpetual so there’s always something cooking. I’ll be starting the LST and training in my 3x3 tomorrow night so In the next few weeks I’ll be getting my 3x3 to full coverage before flipping. Feel free to stop in and ask all the questions you want!