First grow. In 4th week of flowering. Leaves turning yellow and tiny brown spots. Is it a deficiency?. Soil pH is 6.8…water with 6.5-6.8…need help figuring out what is wrong
my guess would be nutrient lockout or deficiency of some kind without any other information such as environment, feeding, watering, etc.
It’s hard to say for sure without a clear photo but yellowing leaves with little brown spots in mid‑flower are often a sign of a nutrient imbalance or pH drift. In soil a range of 6.5‑6.8 is ideal; if your runoff is much higher or lower it can lock out calcium and magnesium, which shows up as rusty spots. A simple flush with pH‑adjusted water and then resuming feed at half strength can help if salts have built up.
Adding a Cal‑Mag supplement and ensuring your bloom nutrients have enough micronutrients can also clear up deficiencies. Check the undersides of the leaves with a loupe for pests like thrips or fungus gnats just to rule that out; they can cause stippling or spots too. Keep an eye on new growth to see if the issue persists after adjusting pH and feeding. Good luck with the rest of your first flower!
Since you’re in soil at 6.8, runoff is the number worth checking before you change anything. If it’s climbing well above your input, salts have built up and a pH-adjusted flush makes sense; if it’s in range, look harder at feeding strength and micronutrients. Yellowing with rusty spots mid-flower often points to calcium or magnesium getting locked out, but that’s a guess without knowing your feed schedule or light distance. Also do the loupe check on leaf undersides for pests before adding supplements, so you’re not treating the wrong thing. New growth tells you more than old leaves.