Brown dots

I have exactly the same problem in my week number 8 of autoflowering plants. I was pretty sure that the deficiency was calcium, I’ve been killing myself trying to figure out what happened, but as @B4RNS says, calcium deficiency can happen due to excess EC, like in my case. I think I have a nutrient lockout due to excess salts in the substrate. As another user solved my doubt earlier, my mistake was over-fertilizing and never letting any runoff water from the pot. Right now I’m considering doing a flush and re-fertilizing with less amount. If you think that excess fertilizers might be an option, maybe you’re going through the same thing I did. Check out my recent questions to compare problems! Best regards!

Just get yourself a pH pen.. consider yourself lucky if you haven’t had issues 2 full grows in. They’re like the price of one seed, it’s a necessity in my mind, but I understand why ppl don’t buy them. Anyhow, no two plants are going to be alike even from the same package/strain.