Deficiency or underfeeding?

Hey! Thanks for the question. First thing are you using LED lights? If so, it could also be a nitrogen deficiency, not just Cal-Mag. Under LEDs, plants often need slightly more nitrogen, and overall EC should be higher compared to HPS setups. Also, check your pH — it plays a big role in nutrient uptake. Hard to say for sure without more details (like feeding schedule, pH/EC, water source, etc), but that’s a good starting point!

You’re right it looks like a little CalMag stress, but mainly it’s underfeeding overall. Your EC is too low for coco – plants in veg usually need around 1.2–1.4 EC minimum. Step up your base nutrients and CalMag together, keep pH at 5.8–6.0. You’ll see them green up quickly once they get enough food.