The journey of Space Cookies & Gorilla

Really thick stems can be a sign of excess calcium. The leaf problems look to me as burning caused by wetting the leaves and having the lights on. Cannabis only really needs extra cal/mag during flowering, any decent "grow" nutrients should have more than enough cal/mag in it to support the plants properly through the vegetative stage. There also seems to be some evidence of too much nutrients. Your plants are still quite young and may not need as much fertilizer as they are receiving. Looking at your diary, there seemed to be a fair bit of "stretching/reaching" for the light going on and this could be a reason for the slow growth you are worried about. Also noticed that your plants are in the corners of your tent, where light intensity is at its weakest. I would try moving the plants into the centre of your tent, directly below the lights. Try also reducing the nutrients to every second watering at the same time as moving them to the centre of the tent. Once they are showing increased growth and are a little larger, you could then go back to your previous feeding routine. The slow growth combined with overfeeding and the position of the plants, could all be contributing to the "less than hoped for" results that are worrying you. Hope this helps.... Organoman.

Some are just yellow spots and of no concern - you will never have 100% perfect leaves 100% of the time. However, other leaves are certainly indicating problems somewhere. I would say, after looking at your diary, the damage is being caused by burning and not any deficiencies of any sort. My guess would be that you are giving bloom booster as well as a P/K booster together and it is more likely your plants are suffering with either phosphorous or potassium over load. My advice would be to just give plain water for the next 3 irrigations to let the substrate leach for a bit to remove any P or K build up, then when you go back to feeding, use only the Ata PK 13/14 or the B'Cuzz universal coco booster separately, and not together in the same feeding. It's one or the other, not both. Your plants will be fine for 3 irrigations of plain water, in fact it is probably wise to use just plain water every third or fourth irrigation to prevent any build up of mineral salts, and your plants will have a chance to scavenge any left over nutrients in the coco before being topped up again. Growth won't be affected, but your coco will stay "cleaner".
Hope this helps..... Organoman.