leaf diseases

Based on the photos provided and the timing (10 days into flowering), what you’re seeing is likely not a "disease," but rather a physiological response. The purple and yellowing patterns on those fan leaves suggest a few distinct possibilities: 1. Phosphorus (P) Deficiency This is the most common reason for purple leaves during early flowering. Plants have a massive spike in phosphorus demand as they transition to building bud sites. The Signs: Purple or dark blue-green hues starting on the lower, older fan leaves, often accompanied by yellowing. The Fix: Ensure you are using a bloom-specific nutrient formula. Check your pH levels; if your root zone is too acidic or too alkaline, the plant cannot "unlock" the phosphorus even if it's there. 2. Temperature Fluctuations (Anthocyanin Production) If your "lights-off" temperatures are significantly lower than your "lights-on" temperatures (a drop of 10-15°F or more), the plant produces anthocyanins. The Signs: This usually looks like a uniform "tanning" or purpling of the leaves. So try to keep your nighttime temperatures above 65°F (18°C). 3. Genetics Some strains are genetically predisposed to turn purple as they mature. However, because yours is accompanied by significant yellowing and it’s happening very early in flower, this is less likely to be "natural" fade and more likely a nutrient issue.