Critical Purple Khush

How often are you watering? Coco can be a little tricky in the early veg stage, until the roots fill out, you should be watering to run off at least once per day. If you don't water enough, with proper PH'd nutrients, you can actually burn your plants and throw off the PH. I had issues with coco until I stopped treating it like soil and started treating it more like hydro.

First I would make sure run off ph is correct so you know soil ph. Since most plants need nitrogen in vegging I would say you are experiencing a nitrogen deficiency. Would add more feed but not a lot it is still young. Good luck and happy growing 🌲🌲🌲👊

To me it seems like an Iron (Fe) deficiency! Do you have a "micro" based fertilizer? you'll need to increase the amount of micro nutrients you add into the irrigation solution. Also make sure to check the pH on the runoff as well to make sure the medium is in proper conditions (what comes out shows the condition of the medium). Might also want to increase the "Mega Crop" dosage by about 10-20% to avoid any other deficiencies. Hope this helps! Good luck and happy growing :)