Oh. Coco. That's a whole 'nother other critter to get used to. I never use it. Can't get it here and it seems to need special care and treatment compared to peat based media like the ProMix HP I've been using for about 10 years.
For sure then you should be feeding a lot more than you are as coco has zero nutes in it and most of what I've read it needs a lot of CalMag from the beginning to condition it as it absorbs both Mg and Ca so that needs to be topped up before the plants get any.
With coco or any soilless media you are basically growing like hydro and must supply everything for your plants.
I would mix up a batch of those nutes at full strength and soak the pot real good with it even if it's already fairly well watered. Flush the old stuff out with the new. It won't need more food for a while but coco should never dry out like you would want with peat based media so should have water added fairly regularly.
Might not be the best food for your plants either. I just checked out FF website and their
Hydro Liquid Trio Pack would be what I would get for growing in soilless. I'm surprised they don't have that made for coco specifically. With that and CalMag you'd be well covered for all the basics in coco tho what you have should work if you give them enough. They say for general feeding it should be 2-3 tsp/gal so you're giving way to little.
General Feeding: 2-3 teaspoons (10-15 mL) per gallon (4 L) of water every other watering.
Heavy feeding: 4 teaspoons (20 mL) per gallon (4 L) of water every other watering.
For best results you should have some bloom formula too.
For an auto 6 weeks in it's a bit late to expect much out of that plant. You might pull a half oz off her if all goes well from now but I'm not at all sure about that.
Got another seed?