Should I be worried about one or two yellow leaves?

Not necessarily, as the plant often sheds older, shaded leaves at the bottom. Only worry if the leaf drop is happening rapidly or across the whole plant.

Can low light cause leaf drop?

Yes, if the plant does not get enough direct light, it will stop supporting its lower foliage. Ensure your plant gets full sun or strong grow lights for at least 12 hours a day.

Why are my cannabis leaves falling off? Causes and fixes

Check these first

Check if the top few centimeters of soil are wet or bone dry.
Inspect the underside of the leaves for signs of pests.
Measure the temperature near the top of the canopy.

Likely causes

Overwatering
Most likely
How to tell: The leaves turn yellow or limp before falling off, and the soil stays soggy for days. You might also notice a sour smell coming from the pot.
What to do: Let the top 3 to 5 centimeters of soil dry out completely before watering again. Ensure your pot has drainage holes so excess water can escape freely.
Extreme Heat Stress
Possible
How to tell: Leaves curl upward at the edges and feel brittle or crispy before dropping. This often happens if the plant is too close to a hot light or in a room over 30 degrees Celsius.
What to do: Move the plant further from your light source or increase ventilation in the grow space. Use a fan to circulate air and keep the temperature between 20 to 25 degrees Celsius.

Find out what's wrong with your cannabis

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

When to worry

If the plant is losing healthy green leaves from the top down, it is a serious sign of distress. It is normal for the plant to shed a few older, lower leaves as it grows larger.

Stopping it coming back

Maintain a consistent watering schedule and keep your grow environment stable to avoid shocking the plant.

Keep your cannabis healthy from here

Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked. Identification and a health check are free.

Get the app · Or check it from a photo now, free

Questions people ask

Should I be worried about one or two yellow leaves?: Not necessarily, as the plant often sheds older, shaded leaves at the bottom. Only worry if the leaf drop is happening rapidly or across the whole plant.
Can low light cause leaf drop?: Yes, if the plant does not get enough direct light, it will stop supporting its lower foliage. Ensure your plant gets full sun or strong grow lights for at least 12 hours a day.

Why are my cannabis leaves falling off?