What's wrong with my cannabis plant?

Nitrogen Deficiency→

Older, lower leaves yellow and fade from the bottom up — the classic sign a cannabis plant is short on nitrogen.

Calcium & Magnesium (Cal-Mag) Deficiency→

Rust-colored spots and yellowing between the veins — the cal-mag combo deficiency common in coco and soft/RO water.

Phosphorus Deficiency→

Dark blue-green leaves with purple/bronze tints and stunted growth signal low phosphorus, often triggered by cold roots.

Potassium Deficiency→

Yellow-then-brown crispy leaf edges with the leaf center staying green points to low potassium.

pH Lockout→

Several deficiencies appearing at once despite feeding — the root-zone pH is out of range and blocking uptake.

Nitrogen Toxicity→

Too much nitrogen turns leaves dark green and glossy with tips that curl down like a claw.

Nutrient Burn→

Brown, crispy leaf TIPS from overfeeding — the most common beginner mistake from running nutrients too strong.

Overwatering→

Droopy, swollen, dark leaves with constantly-wet soil — roots are suffocating from too much water.

Underwatering→

Limp, thin, wilted leaves with bone-dry, light medium — the plant simply needs water.

Light Burn→

Yellowing or bleaching on the TOP leaves and colas nearest the light — too much intensity or lights too close.

Heat Stress→

Upward-cupping ("tacoing") leaves and crispy edges on the top canopy when the grow space runs too hot.

Spider Mites→

Tiny pinprick speckling on leaves and fine webbing — spider mites, one of the fastest-spreading cannabis pests.

Powdery Mildew→

White powdery patches on leaves and stems — a fast-spreading fungal infection driven by humidity and poor airflow.

Bud Rot (Botrytis)→

Buds rotting from the inside out — gray/brown mold (botrytis) that can destroy a flowering crop fast.

Root Rot→

Brown, slimy, foul-smelling roots that stall the whole plant — root rot, most common in warm or low-oxygen root zones.