Plant problems · Light, heat and air · Any stage · Act this week
Heat stress
What you see
- Leaves fold upwards along the middle like a taco
- Edges curl up and look dry
- Buds grow airy, fluffy or form small spires (foxtails)
- The room is above about 30 C at canopy height
Why it happens
Too much heat at the top of the plant, from lights, a hot room or no air exchange.
What to do
- Measure the temperature at the top of the plant, not on the wall
- Raise or dim the light and add an extraction fan or a clip fan across the canopy
- Run the lights during the cooler night hours in summer
Next time
- Keep the canopy at 22 to 28 C with lights on
- Plan extraction before summer
Easy to confuse with
- Underwatering: Leaves hang limp and soft, like they have no strength
- Light burn and light bleaching: The top leaves closest to the light turn yellow or white while their veins stay green
- Air too dry: Leaves curl and feel thin and dry
Not sure?
Take a photo of leaves at the top, side on, so the taco shape shows and ask the Grow Doctor, or send it to the grow companion on Telegram.