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
- Stickstoffmangel: Lower, older leaves turn pale green, then evenly yellow from the tip inwards
- Zu viel Stickstoff (die Kralle): Leaves are very dark green, almost shiny
- Phosphormangel: Dark, dull or bluish green leaves with brown to purple patches, often on older leaves
- Kaliummangel: Leaf edges and tips turn yellow, then brown and crispy, starting on older leaves
- Calcium-Mangel: Small brown spots with sharp edges on new and middle leaves
- Magnesiummangel: Yellowing between the veins of older and middle leaves while the veins stay green
- Eisen-Mangel: The newest leaves turn pale yellow while their veins stay green
- Schwefelmangel: New leaves turn evenly lime green or yellow, veins included
- Zinkmangel: New leaves are small, narrow and wrinkled
- Manganmangel: Yellowing between veins on new and middle leaves with a thin green border along the veins
- Bor-Mangel: Growing tips die back or grow hollow and twisted
- Nährstoffbrand: Leaf tips turn yellow, then brown and crispy, a few millimetres in
- pH-Blockade: Several deficiencies at once: yellowing, spots and burnt edges together
Water and roots
- Überwässerung: The whole plant droops with leaves that feel firm and swollen, not limp
- Unterwässerung: Leaves hang limp and soft, like they have no strength
- Wurzelfäule: The plant wilts even when the medium is wet
Light, heat and air
- Lichtbrand und Ausbleichen: The top leaves closest to the light turn yellow or white while their veins stay green
- Hitzestress: Leaves fold upwards along the middle like a taco
- Kältestress: Leaves and stems turn purple (beyond what the strain normally shows)
- Luft zu trocken: Leaves curl and feel thin and dry
- Luft zu feucht: Water drops on leaves or walls in the morning
- Fuchsschwanz-Blüten: Small spires of new calyxes stack on top of the buds
- Vergeilte, gestreckte Sämlinge: Long thin stems that fall over
- Windbrand: Leaves near a fan are clawed, dry or torn
- Zwitter und Bananen: Yellow banana shaped growths (nanners) appear between the buds
Pests
- Spinnmilben: Tiny white or yellow dots on the top of leaves
- Thripse: Silvery, shiny scratches on leaves
- Trauermücken: Small black flies around the soil surface
- Blattläuse: Clusters of small soft green, black or white insects under leaves and on new shoots
- Weiße Fliegen: Small white flying insects that rise when you touch the plant
- Raupen und Blütenwürmer: Holes eaten in leaves
- Rost- und Breitmilben: Leaves curl up at the edges and turn shiny, glossy or bronze
- Wurzelläuse: Plants stall and yellow without a clear reason
Diseases
- Echter Mehltau: White, flour like patches on the top of leaves
- Blütenfäule (Botrytis): A bud has brown, dry or slimy parts inside
- Septoria-Blattflecken: Round yellow spots on lower leaves that turn brown with a yellow halo
- Umfallkrankheit: A seedling suddenly falls over
- Fusarium-Welke: Leaves yellow and wilt on one side or one branch first
- Hop latent viroid (HLVd): Plants grow smaller than expected and stay stunted
Handling and timing
- Eine männliche Pflanze: Small round balls on short stems where branches meet the main stem
- Umpflanzschock: The plant droops for a day or two after repotting
- Samen keimen nicht: No taproot after 5 to 7 days
- Gestoppter Autoflower: An autoflower starts flowering while still very small
- Zu früh oder zu spät geerntet: Early: most trichomes are still clear, pistils mostly white, effect thin and racy