Help a new grower ID this issue please!

Ca,Mg,P lockout due to K excess soon 'll be N

Beginning of a magnesium deficiency.

Watering issue , roots lack oxygen, no wet/dry regime witch is essential for soil, thats why magnesium issues are starting.

Hi, Raise the humidity to 75% and only start reducing it when the early flowering phase begins. It looks like light stress. Are you already giving your plants nutrients? If not, start immediately! They need nitrogen, calcium, and magnesium (CalMag). Also, check your light intensity—300–400 PPFD would be good for now. Oh, and your pH should be around 5.8–5.9 at the beginning and slightly increase over time. No worries, they will recover.

The plant doesn’t need that kind of watering everyday just yet, still too small. Definitely on the lower end of the PH scale if you’re letting it get down to 5.6. I grow in DWC and keep mine at 6.2. Temp, rh, and nutrient ppm for this stage seem to be fine.

Ssuonds like bad watering habits. You chose a nice round number to give each day? 500mL? 1) fulll saturate with 10% excess runoff waste water ('drain to waste') -- this is the most important thing for soilless growing, which coco is. coco is merely a soilless substrate. it is not magical or different in any meaningful way to other options. this 'waste' water can be used on plants in the ground, but not potted plants, if you don't want to throw it out. 2) Wait for top layer to start to change color and repeat. So, the volume of water needed is dictated by the substrate constition and how long you wait between irrigation (how much plant drinks). Not a number you pull from the ether. You give what it takes to accomplish the job. This alone may fix any minor problems seen. The wrinkly nature and the blotchiness on 3-finger leaf might be a matter of early growth. Time will tell. It's worth being patient because it may be nothing. Wait a bit before reacting. The pH going down to 5.6 is definitely somethign you want to avoid. That'll quickly cause issues with Ca. Good soilless fertilizer should not require pH balancing. They should come buffered to a proper pH and resistant to drift. if not the case, look for a better product. as long as it was buffered properly, coco doesn't need more/less Ca. It needs exactly what a plant always needs. the plant's use dictates not the physical medium the water is absorbed into. Unprocessed coco will temporarily leach Ca, but that is only if it's a trash product from a trash manufacturer. Your plants would be sickly looking if that were the case and maybe even die. Unprocesses coco is dangerousAF to plants, lol. go read the guides on cocoforcannabis.com - the articles and guides section. that is good info you can follow and get be confident in consistent results occurring.

It could, in deed, be low on the PH side. I am always around 6.1 to 6.3. I also add Cal-Mag if I have a slight coloration issue. That usually does the trick. Some people use a slight amount of epsom salt, which is just magnesium, like found in the Cal-Mag.

PH is to low IMO. I'd aim for 6.2, give yourself some room to wiggle. 5.8 or lower is so close to cutoff and lockout and PH drifts in the medium. Any liquid fertilizer that is readily available will have a broad range for uptake by the plant. 5.8-7.5, the lower PH on DWC is more so to help control the other things that grow in the water from my understanding. I'd try that bit first, also water when it needs it. not a specific amount daily. be religious about runoff to prevent buildup and correct the feeding concentration based off of the plant needs. It will tell you if its to much or or little. This is a good starting point for EC range on plants. https://www.thcfarmer.com/threads/med-man-method-ppm-ec-chart.73326/ Its not 100% so alther it when needed.