Plants & climate
Humidity, heat and watering
Read temperature and humidity together. The same relative humidity at different temperatures does not create the same drying demand on a plant.
Check with FernFind your next step →Plant doctor · WITH PROFESSOR COCO
White powder on leaves: is cocopeat the cause?
White marks on leaves need identification. Powdery mildew is a leaf disease; visible white material can also be spray or mineral residue.
Teral grower guidance · Updated 27 October 2026
Professor CocoYour plant doctor guideTHE COCOPEAT CONNECTION
Why the root zone matters
A plant growing in cocopeat can still develop canopy disease. Changing the substrate alone will not correct a leaf-level problem or unsuitable greenhouse conditions.
01 / OBSERVE
Three checks before you change anything
- Photograph both leaf surfaces and note whether patches are spreading to new leaves or nearby plants.
- Review recent spray applications and whether deposits follow splash or droplet patterns.
- Check canopy crowding, airflow, light and crop susceptibility. Powdery mildew does not depend on wet leaves in the same way as many other diseases.
02 / NARROW IT DOWN
What have you observed?
Choose the closest observation for a suggested next check.
Patches are spreading
Seek confirmation from your crop adviser. Review spacing and canopy conditions and use locally approved controls only after identification.
Marks appeared after a spray
Check the product and application record. Compare unsprayed leaves before assuming disease.
Not sure what the white material is
Send clear close-up and whole-plant photos for identification. Avoid treating an uncertain diagnosis.
03 / TAKE THE NEXT STEP
Leave with something useful
Confirm what the white material is, then choose a crop-specific management plan.
Keep in mind
Do not replace cocopeat or repeatedly spray based on colour alone.
Discuss this with Teral →Watch the related Growlab lessons
The written checks above stand on their own. These short lessons add context.
Lesson links selected from Growlab’s supplied transcript and description review.
CONNECTED QUESTIONS
