Troubleshooting
Cape Sundew problems — and how to fix them
Cape Sundew (Drosera capensis) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Tentacle loss and leaf blackening from tap water
Dissolved minerals and chlorine in tap water accumulate rapidly in the nutrient-sensitive root zone; even brief use can cause tentacle dieback and root damage. Switch immediately to rainwater or distilled water and flush the medium with several volumes of mineral-free water.
Fungus gnats
Larvae colonise the moist, peaty substrate and damage roots; yellow sticky traps catch adults and help monitor population size. Allowing the surface of the medium to dry very slightly between top-ups (while still keeping the tray method for root moisture) reduces larval survival.
Failure to trap (inactive tentacles)
Inactive or pale tentacles indicate insufficient light; move the plant to a brighter position or supplement with a full-spectrum LED grow light positioned 15–20 cm above the rosette for 12–14 hours daily.
Prevent cape sundew problems before they start
Most cape sundew issues are care-mismatch, not bad luck. Dial in the basics:
Cape Sundew problems — FAQ
Why is my cape sundew tentacle loss and leaf blackening from tap water?
Dissolved minerals and chlorine in tap water accumulate rapidly in the nutrient-sensitive root zone; even brief use can cause tentacle dieback and root damage. Switch immediately to rainwater or distilled water and flush the medium with several volumes of mineral-free water.
Why is my cape sundew fungus gnats?
Larvae colonise the moist, peaty substrate and damage roots; yellow sticky traps catch adults and help monitor population size. Allowing the surface of the medium to dry very slightly between top-ups (while still keeping the tray method for root moisture) reduces larval survival.
Why is my cape sundew failure to trap (inactive tentacles)?
Inactive or pale tentacles indicate insufficient light; move the plant to a brighter position or supplement with a full-spectrum LED grow light positioned 15–20 cm above the rosette for 12–14 hours daily.