A single branch wilting or dying

Likely causes, most likely first

Ranked for this sign on its own. Your stage, medium and readings change the order, so run the checker for your plant.

1. PossiblePhysical damage (kinks, splits, broken branches)

   Physical damageDeal with it this weekRead: HST and supercropping: controlled stem crushing

   Fix: Splint and tape a split stem within hours (tape, plant tie or a straw splint); a supercropped knuckle heals stronger in 3-7 days. Remove fully broken branches with a clean cut. Support heavy colas with a trellis.

   Recovery: Leaves above the wound regain turgor within 1-2 days; a callus forms within a week.

   How to confirm it

   • Cut a wilting stem lengthwise. On a wilting or dying branch, scrape the lower stem and cut it lengthwise with a clean blade. Brown streaks in the water-conducting tissue point to vascular wilt (Fusarium). A dark, sunken crown points to crown rot. Disinfect the blade afterwards.

2. PossibleFusarium wilt or crown rot

   DiseaseAct within a day or twoRead: Fusarium in cannabis: wilt, crown rot and bud rot

   Fix: No cure once infected: remove the plant with its medium in a bag, sanitise pots, trays and water lines, and use clean clones and new media. Reduce root stress (overwatering, heat, salts) on the rest.

   Recovery: No further wilting plants over the next 2-3 weeks.

   How to confirm it

   • Cut a wilting stem lengthwise. On a wilting or dying branch, scrape the lower stem and cut it lengthwise with a clean blade. Brown streaks in the water-conducting tissue point to vascular wilt (Fusarium). A dark, sunken crown points to crown rot. Disinfect the blade afterwards.
   • Send a sample to a plant diagnostic lab. For rots, wilts, leaf spots and viruses you can't separate by eye, send a fresh sample (whole plant with roots or a wilting branch with healthy and diseased tissue) in a sealed bag to a university or commercial plant diagnostic clinic. Results in days to 2 weeks.
   • Look at the roots. Hydro: lift the net pot and look at the root mass in good white light. Containers: tip the plant out with a hand over the medium and look at the edges and bottom of the root ball. Healthy roots are white to cream with fine fuzzy tips. Brown roots whose outer layer slides off between the fingers leave a bare thread: rot. Firm, evenly tan roots with white tips in coloured solution are staining.

Look for

The wilted branch and its junction with the main stem; look for a kink, split, crack or brown streak inside the stem..