Problem: Your cannabis plant can only withstand a certain amount of light. After a certain point, your cannabis will start turning yellow or otherwise exhibit signs of stress on the leaves near the sources of light and/or heat.
How far away do I keep grow lights from my plants?
Light burn usually causes yellow leaves at the top of the plant directly under the grow lights (though it can appear on older leaves that have been exposed for a long time).
This light burned leaf is not happy…
Sometimes the first sign a plant is getting too much light is all the leaves start pointing up, (though sometimes you don’t see any symptoms until the yellowing starts)
Example of a cannabis plant that is getting too high levels of light so all the leaves are pointing up
With light burn, often the inside veins stay green. Yellow leaves won’t fall off or be plucked off easily, unlike a nitrogen deficiency where leaves fall off on their own