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cannabis leaves turning yellow

What do you do to fix yellow cannabis leaves? Share your feedback in the comments below.

Wednesday January 29, 2020
If your yellow leaves come with spots or bite marks, they’re probably infested with pests. Though you can often see the infestation, this is not always the case – a tell-tail sign (aside from the remnants of the buffet) is a plant that lacks vigor in addition to other symptoms associated with things like overwatering or poor air circulation.

If you notice yellowing toward the top of the plant (specifically, nearest the light source), your plants are likely suffering from light burn. Light burn can happen in temperature-controlled environments as easily as those in high-heat if the leaves get too close to the lights. We liken this to getting a sunburn on the ski slopes.
The most common reason plant leaves turn yellow is because of stress. Whether due to inadequate watering, excessive heat, or pest infestations, yellow leaves are a sign of sickly cannabis plants and must therefore be addressed as soon as possible. To understand the science behind this, we must first look at the contents of a typical leaf and its relationship to the plant’s overall health.
Leaves are made up of plant cells. Plant cells are made up of organelles called chloroplasts. These chloroplasts contain pigments that absorb different wavelengths of light. Though most of these pigments are green chlorophyll, other pigments are also involved. Most notable are the yellow and orange carotenoids that hide under the dominant chlorophyll.
Growing your own marijuana is very rewarding, but it can be really nerve wracking, too, especially when those bright green leaves start turning a worrisome yellow. If your cannabis leaves are turning yellow, use these steps to stop the yellowing before it’s too late.
Fear not fellow cannabis cultivators! Just because your cannabis leaves are turning yellow does not mean they are done-for. In fact, there are steps you can take right now to correct yellow cannabis leaves and prevent it from occurring again. But first, let’s discuss why cannabis leaves turn yellow in the first place

After measuring and adjusting pH, take a look at your watering schedule. The most common cause of yellow leaves is either over- or under-watering. Plants that are over-watered will have leaves that seem swollen and droopy while under-watered plants (though much less common) will be thin and frail. Poor drainage can also contribute to overwatering so always grow your cannabis in pots with drain holes.

Does your cannabis grow have plants with yellow leaves? Yellowing marijuana leaves can indicate a variety of common ailments. Keep reading to learn more about cannabis plant health and tips to overcome yellow leaves.

Cannabis leaves turning yellow

Occassionally a nitrogen toxicity is mistake for a deficiency. Could your plant actually be nitrogen toxic? (pictured below)

Don’t worry about yellow leaves close to harvest! It’s normal to see a few Nitrogen-deficient leaves in the flowering stage. Nothing to worry about unless you see the yellowing leaves start climbing up the plant.
Nitrogen is especially important during the vegetative stage of your cannabis plants. As your plants start flowering, they will need lower amounts of nitrogen.

Example of cannabis Nitrogen deficiency – yellow bottom leaves. Almost all plant nutrients contain Nitrogen
Nitrogen is a mobile nutrient, which means it can move throughout the plant as needed. Cannabis needs nitrogen to keep leaves green and make energy from light. All new leaves get plenty of nitrogen to make them green and help with photosynthesis. The leaves that get the most light are the newest, youngest leaves, so the plant “wants” to give those leaves priority for getting light.
Vegetative Stage – higher levels of Nitrogen (pretty much any plant food will do)
Note: During the last few weeks before harvest, marijuana plants start pulling all the remaining nitrogen from her leaves as part of the bud-making process. This causes yellowing leaves starting towards the bottom of the plant. This is part of the natural flowering process and you don’t need to fight it. You may notice that marijuana leaves are yellowing in almost all pictures of marijuana plants with big buds that are close to harvest. You tend to get smaller yields from nitrogen-toxic plants with dark green leaves at harvest.
Nitrogen-deficient plants often appear pale or lime-colored. The leaves on this marijuana plant don’t have obvious leaf symptoms like spots or markings, but they are pale all over the whole plant. Almost lime green. The light-colored leaves are a sign the plant needs more Nitrogen (and nutrients in general). On the flip side, plants that are receiving too much Nitrogen turn dark.

Problem: A cannabis nitrogen deficiency will cause the older, lower leaves on your plant to turn yellow, wilt away and eventually die. The plant typically appears pale or lime-colored.

A nitrogen deficiency causes the lower/older leaves of a cannabis plant to start yellowing, wilting, and dropping off on their own. Learn how to fix it.