I'm on day 15 of veg and my plants seem to be developing yellow spots. One of the 5 plants isn't growing very much and the bottom most leaves are yellowing. Another plant has one leaf with a curled and yellowing tip. The other plants seem to be doing fine. The plants haven't gotten any nutrients and I haven't been over watering (as far as I can tell). I checked the pH of the runoff in each cup and it's right around 7. I recently bought the biobizz starter set so if it's a lack of nutrients I can adjust it fairly quickly. The plants are under a 200W CFL and the temp. is always between 70 and 80 degrees with a humidity of roughly 50%. Anybody have any suggestions on what the problem could be?
Yes, I agree with pinkbear. Def. looks like nute burn, try flushing it with filtered water or bottled water, if you aren't already, it should help.
I have them in "Compo Sana" dirt and have been using filtered water the entire grow. A friend of mine has used the dirt multiple times and it seems to do fine...
Honestly I wouldn't worry about it unless it spreads to 2nd set of leafs. I would try and get PH to 6.4-6.8 in the long run it will be much better for the plants. If your letting it get dry atleast an inch or two down before watering. I bet they grow out of it. From what Ive seen roots reach the bottom of those size cups pretty quick. I would recommend transplanting into a 1 gal root pot (there are many brands like this) less than 2$ and work amazing.