# Cuttings wilting: likely causes and fixes

> Cuttings wilting on cannabis is most often Cuttings losing water faster than they can root, Air too dry / VPD too high or Fungus gnats. How to tell them apart, the fix for each and what recovery looks like.

Also called: clones wilting, clones drooping, cuttings flopped, clones not rooting and wilting.

Run the checker with this sign: https://genetixbay.com/knowledge/diagnose/?at=whole&s=clone-wilting

## Likely causes, most likely first

### Cuttings losing water faster than they can root (Possible)

- Kind: Environment; urgency: Deal with it this week
- Fix: Keep clones at about 75-90% RH (VPD ~0.4-0.8 kPa), 22-26 °C (72-79 °F), PPFD 100-200 µmol/m²/s; trim large fan leaves by half; vent the dome gradually only once roots show.
- Recovery: Cuttings stand up within 24 h; roots in 7-14 days.
- Confirm: Check temperature and RH at canopy height with a calibrated sensor: Put a calibrated sensor (salt test: a sealed bag with damp table salt reads 75% RH after 8-12 hours) at canopy height, out of direct light, and log for 24 hours including lights-off. Look for lights-off RH spikes and dew point.
- Confirm: Measure PPFD at the canopy top: Use a quantum (PAR) meter, or a calibrated phone app as a rough guide, at the top leaves in a 5-9 point grid. Compare with the stage target: seedlings 100-300, veg 300-700, flower 800-1,200 µmol/m²/s at ambient CO2. Bleaching and taco at the top above ~1,100 point to light; stretch below ~300 in veg points to too little.
- Article: [Why are my clones wilting?](https://genetixbay.com/knowledge/answers/why-are-my-clones-wilting.md)

### Air too dry / VPD too high (Possible)

- Kind: Environment; urgency: Deal with it this week
- Fix: Raise RH or lower temperature to bring leaf VPD to 0.4-0.8 kPa (clones, seedlings), 0.8-1.2 (veg), 1.0-1.5 (flower). Humidifier, less exhaust when cool, fewer dry hot air inputs. Dry air also speeds spider mites.
- Recovery: Leaves flatten within a day.
- Confirm: Check temperature and RH at canopy height with a calibrated sensor: Put a calibrated sensor (salt test: a sealed bag with damp table salt reads 75% RH after 8-12 hours) at canopy height, out of direct light, and log for 24 hours including lights-off. Look for lights-off RH spikes and dew point.
- Confirm: IR leaf temperature at the canopy top: Point an IR thermometer at the top leaves under the light (5-10 cm away, emissivity 0.95) and at shaded leaves. Leaf temperature above about 30 °C (86 °F) at the top only points to heat or radiant load; leaf VPD can be calculated from leaf temperature and RH.
- Article: [VPD explained: vapour pressure deficit for cannabis growers](https://genetixbay.com/knowledge/environment/vpd-explained.md)

### Fungus gnats (Possible)

- Kind: Pest; urgency: Low urgency
- Fix: Fix the watering first: let the top 2-3 cm dry. Then Bti drenches (larvicide), Steinernema feltiae nematodes or Stratiolaelaps mites; yellow cards for adults. Larvae chew seedling and clone roots and can open the door to Pythium.
- Recovery: Card catches fall within 2-3 weeks; no larvae under potato slices.
- Confirm: Sticky cards for 1-2 weeks: Hang yellow cards at canopy height and lay one flat on the medium surface; add blue cards for thrips. Count catches every 3-4 days. Rising counts of small dark flies at the medium mean fungus gnats; slender insects mean thrips; white wedge-shaped fliers mean whiteflies; winged aphids mean a colony nearby.
- Confirm: Potato slice test for larvae in the medium: Press 2-3 raw potato slices (1 cm thick) cut side down onto the medium surface. Lift after 2-4 days and look underneath: translucent larvae with shiny black heads are fungus gnat larvae.
- Article: [Fungus gnats: the watering problem with wings](https://genetixbay.com/knowledge/pests/fungus-gnats.md)

### Chlorine or chloramine in tap water harming roots and soil life (Less likely)

- Kind: Root zone; urgency: Low urgency
- Fix: Usual tap levels rarely hurt the plant directly; the concern is living soil, beneficial microbes and young roots. Chlorine gasses off in 24 h of aeration; chloramine does not. Remove chloramine with long-contact or catalytic carbon, or about 1 g of ascorbic acid per 100-400 L, or use RO.
- Recovery: Biology recovers over weeks; seedlings resume growth within a week.
- Confirm: Get a water report (or test your water): Ask your water utility for the annual report or test well water: alkalinity (mg/L CaCO3), pH, EC, Ca, Mg, Na, Cl, B, and whether it uses chlorine or chloramine. Alkalinity above ~100-150 mg/L as CaCO3 pushes root-zone pH up; sodium above ~50 mg/L and chloride above ~70 mg/L are a problem; softened water is high in sodium.
- Article: [Water quality for cannabis: RO vs tap, alkalinity, bicarbonates and chloramine](https://genetixbay.com/knowledge/ph-ec/water-quality.md)

## Note

Guidance, not a guarantee. The checker weighs common causes against what you tell it; confirm with the tests before you treat, change one thing at a time and watch the new growth.