Cannabis plant problems
Find what is wrong with your plant by what you see, then fix it. Not sure? Send a photo to the Grow Doctor.
Nutrients
- Carence en azote: Lower, older leaves turn pale green, then evenly yellow from the tip inwards
- Excès d'azote (la griffe): Leaves are very dark green, almost shiny
- Carence en phosphore: Dark, dull or bluish green leaves with brown to purple patches, often on older leaves
- Carence en potassium: Leaf edges and tips turn yellow, then brown and crispy, starting on older leaves
- Carences en calcium: Small brown spots with sharp edges on new and middle leaves
- Carence en magnésium: Yellowing between the veins of older and middle leaves while the veins stay green
- Carences en fer: The newest leaves turn pale yellow while their veins stay green
- Carence en soufre: New leaves turn evenly lime green or yellow, veins included
- Carence en zinc: New leaves are small, narrow and wrinkled
- Carence en manganèse: Yellowing between veins on new and middle leaves with a thin green border along the veins
- Carence en bore: Growing tips die back or grow hollow and twisted
- Brûlure nutritive: Leaf tips turn yellow, then brown and crispy, a few millimetres in
- Blocage de pH: Several deficiencies at once: yellowing, spots and burnt edges together
Water and roots
- Excès d'eau: The whole plant droops with leaves that feel firm and swollen, not limp
- Manque d'eau: Leaves hang limp and soft, like they have no strength
- Pourriture des racines: The plant wilts even when the medium is wet
Light, heat and air
- Brûlure lumineuse et blanchiment lumineux: The top leaves closest to the light turn yellow or white while their veins stay green
- Stress de chaleur: Leaves fold upwards along the middle like a taco
- Stress de froid: Leaves and stems turn purple (beyond what the strain normally shows)
- Air trop sec: Leaves curl and feel thin and dry
- Air trop humide: Water drops on leaves or walls in the morning
- Bourgeons en épi: Small spires of new calyxes stack on top of the buds
- Semis étirés et longilignes: Long thin stems that fall over
- Brûlure éolienne: Leaves near a fan are clawed, dry or torn
- Hermaphrodites et bananes: Yellow banana shaped growths (nanners) appear between the buds
Pests
- Tétranyques tisseurs: Tiny white or yellow dots on the top of leaves
- Thrips: Silvery, shiny scratches on leaves
- Sciaridés: Small black flies around the soil surface
- Pucerons: Clusters of small soft green, black or white insects under leaves and on new shoots
- Mouches blanches: Small white flying insects that rise when you touch the plant
- Chenilles et vers des bourgeons: Holes eaten in leaves
- Acariens roussâtres et tétranyques larges: Leaves curl up at the edges and turn shiny, glossy or bronze
- Pucerons des racines: Plants stall and yellow without a clear reason
Diseases
- Oïdium: White, flour like patches on the top of leaves
- Pourriture des bourgeons (botrytis): A bud has brown, dry or slimy parts inside
- Tache septorienne: Round yellow spots on lower leaves that turn brown with a yellow halo
- Pourriture de la tige: A seedling suddenly falls over
- Flétrissement fusarien: Leaves yellow and wilt on one side or one branch first
- Viroïde latent du houblon (HLVd): Plants grow smaller than expected and stay stunted
Handling and timing
- Un mâle: Small round balls on short stems where branches meet the main stem
- Choc de repiquage: The plant droops for a day or two after repotting
- Graines qui ne germent pas: No taproot after 5 to 7 days
- Autofloraison rabougrie: An autoflower starts flowering while still very small
- Récolté trop tôt ou trop tard: Early: most trichomes are still clear, pistils mostly white, effect thin and racy