Nutrient Burn

Nutrient burn (commonly called "nute burn") is one of the most frequent grower mistakes and the most visually diagnostic cannabis health issue. The condition occurs when nutrient salts accumulate in the root zone faster than the plant can metabolize them, causing osmotic stress that pulls water out of leaf cells via the xylem reverse-flow process. The damage starts at leaf tips because tip cells are the farthest from the stem and accumulate excess salts as transpirational water evaporates from the leaf surface. Visible symptoms: leaf tips yellow then brown and curl downward, the burned tissue becomes crispy and brittle, damage progresses inward toward the leaf center if feeding continues at the same strength, lower leaves are affected first as they accumulate the most cumulative salt exposure. Causes: feeding at EC above plant tolerance for the lifecycle stage (above 2.6 mS/cm for flowering cannabis is the typical danger zone), inadequate runoff allowing salt buildup in the medium, switching nutrient brands without lowering concentration, or combining base nutrients with too many additives (Cal-Mag, sweeteners, boosters). Some strains are more sensitive than others — autoflowers and many sativa-dominant strains tolerate only 60-75% of the EC tolerated by indica-dominant photoperiods. Treatment: immediately flush the growing medium with pH-balanced plain water at 2-3x container volume to wash out accumulated salts, then resume feeding at 50% reduced strength until new growth shows healthy green tips. Damaged leaf tissue does not recover but the plant can grow new healthy leaves above the burned ones. Prevention: always start new strains at 50% recommended nutrient strength and increase gradually based on plant response; monitor runoff EC alongside feed-in EC.