If the yellowing leaves are at the top of your plant or the yellow leaves are mostly new growth, then you probably don’t have a nitrogen deficiency. Nitrogen deficiencies usually affect the oldest, lowest leaves first, or the entire plant becomes light colored.
The very first number, “3” in the case of the picture to the right, always displays the proportion of nitrogen in this nutrient bottle compared to the other 2 nutrients (Phosphorus and Potassium respectively).
Solution: You can find many pre-mixed nutrients from the store which contain nitrogen or you could use nitrate of soda or organic fertilizer which are both good sources of nitrogen. In fact almost all plant nutrients of any kind will include nitrogen. If you haven’t been providing any nutrient to your plants, try supplementing your regular nutrients with a bit more nitrogen and see if the plant starts recovering.
If you can’t order online and can’t find a good one-part base Bloom formula locally, you do have other choices. Though not an ideal choice, most Cactus plant foods will contain good nutrient ratios for growing cannabis during the budding stage. So in a pinch, you can use the cactus nutrients that can be found at most gardening stores.
If you notice your lower cannabis leaves turning yellow in the vegetative stage or in the beginning part of the flowering stage, your plant may be experiencing a nitrogen deficiency which will need to be treated.
You don’t want a nitrogen deficiency in the vegetative stage!
When looking at plant nutrients, you’ll almost always see 3 numbers listed, like 3-12-6 or 5-10-5. These numbers represent the percentage of Nitrogen (N), Phosphorous (P) and Potassium (K) contained in the bottle. Just about all plant life on Earth needs these 3 elements to grow.
Some examples of cannabis-friendly one-part Vegetative nutrient systems…
Nitrogen is in all plant nutrient formulations because it’s vital to plant processes.
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.
The roll of chlorophyll is to absorb sunlight and transform it into energy via a process called photosynthesis. When plants have ample access to resources, chlorophyll thrives. When plants are stressed, however, the chlorophyll begins to degrade revealing the yellow carotenoids below.
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.
Note that carotenoids cannot directly transform light into energy via the photosynthetic pathway and must pass it onto chlorophyll to finish the job. Therefore, while a minor yellowing leaves will not stop photosynthesis, excessive or unaddressed yellowing can either stunt plant growth or kill the whole thing entirely.
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
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.
The first thing you should do when cannabis leaves start to turn yellow is to measure the pH of your grow medium (soil, water, rice hulls, expanded clay, etc.). That’s because an improper pH balance – whether too high or too low – can actually block nutrient absorption.
Temperatures outside of the ideal range of 70 to 80 degrees Fahrenheit also risk discoloration and curl leaves. These oddities are most common in leaves toward the top of the plant and can easily be remedied with a fan (if too hot) or root insulation (if too cold). We also recommend growing plants off a cold cement or tile floor; use a milk crate or stool to raise them off the ground when necessary.
What do you do to fix yellow cannabis leaves? Share your feedback in the comments below.
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.
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.