Yellow spots and Brown spots!

Yellow and brown spots on leaves in autoflower cannabis plants can come from a variety of causes. Given your setup and feeding approach, here are the most likely causes and how to check them: --- 1. Nutrient Deficiency (Underfeeding) You mentioned using half the recommended dose of nutrients — while cautious feeding is smart for autos, it can lead to deficiencies, especially in calcium, magnesium, nitrogen, or potassium. Calcium deficiency: Brown spots, often on newer growth. Magnesium deficiency: Yellowing between veins (interveinal chlorosis), sometimes rusty spots. Potassium deficiency: Yellowing edges, brown tips or spots. Nitrogen deficiency: Older leaves turn yellow and may drop off. What to do: Try increasing nutrients slightly to 75% of recommended dose, especially Cal-Mag if not already included. Make sure you're feeding with a balanced nutrient mix for autos. --- 2. pH Imbalance Peat-based soils can be acidic, and if pH is off, nutrients can be locked out even if present. Cannabis prefers a soil pH of 6.0 to 6.5. If it's too acidic or alkaline, nutrient uptake is reduced. What to do: Test runoff pH with a cheap pH meter or test kit. If it's out of range, flush with pH-balanced water and correct accordingly. --- 3. Overwatering / Poor Drainage Even with perlite and clay, peat holds water, and overwatering can cause root issues, leading to leaf discoloration. Symptoms: droopy plants, yellowing, or spotty leaves. What to do: Let the top inch of soil dry before watering again. Ensure containers have good drainage. --- 4. Light Burn or Heat Stress If yellow/brown spots are on upper leaves or directly under lights, it could be light burn. What to do: Check distance from light to canopy. Ensure good airflow and temp below 28°C (82°F). --- Summary: Start by checking: Runoff pH Nutrient dosage, especially Cal-Mag Watering habits Light distance