Learn the causes of yellow cannabis leaves

Learn the causes of yellow cannabis leaves

If your cannabis leaves have started to turn yellow, there are a few potential causes that you need to investigate. The first step is to correctly diagnose the problem, as different causes require different solutions.

Here are some of the most common reasons why cannabis leaves turn yellow:

Yellow Marijuana Leaves

Yellow Marijuana Leaves? How to Obtain an Accurate Diagnosis

The yellowing of leaves is called chlorosis. This is a process wherein plant leaves lose their chlorophyll (the compound that keeps them green).

Chlorosis may be the result of a specific issue (environmental problems, sunlight deficiency, etc), or it may simply be due to senescence – the process of change due to the natural aging of a plant.

No matter the cause, it’s important to determine what’s causing your plants to turn yellow and take corrective action as soon as possible. In this article, we will explore several possible causes of chlorosis and offer some solutions.

One of the most common reasons for leaves to turn yellow is a lack of nutrients. This is often caused by over-fertilization, but can also be due to poor soil quality or an incorrect pH level.

Yellow Marijuana Leaves? How to Obtain an Accurate Diagnosis

1-Light Deficiency

There are a few different types of lighting you can use for growing cannabis: incandescent, fluorescent, high-pressure sodium (HPS), or metal halide (MH). Each type has its own benefits and drawbacks,

so you’ll need to do some research to figure out which type is best for your grow.

Incandescent bulbs are the cheapest and most inefficient type of grow light. They produce a lot of heat, which can be dangerous and can also damage your plants. For this reason, incandescent bulbs should only be used as a supplemental light source.

Fluorescent lights are a good option for small-scale grows. They’re affordable and produce very little heat, making them safe for use in an enclosed space.


When growing cannabis, it’s important to use the right kind of light. HID (high-intensity discharge) bulbs are best for cannabis seedlings, but in a smaller grow room where heating becomes an issue,

LEDs are a decent substitute. You’ll need to move the lights as the plant grows taller, though.

2- Watering Issues

If you’re not sure how to water your cannabis plants, it’s important to do some research first. Too much water can kill your plants, while under-watering can also lead to chlorosis. It’s a tricky balancing act, but following these simple tips should help:

  • Start by reading up on the specific needs of your cannabis plant. Every strain is different, so you’ll need to tailor your watering schedule to their specific requirements.


The solution to overwatered plants is simple: stop watering them! If your plants are in a pot, make sure the pot has drainage holes so that excess water can escape. If your plants are in the ground, consider installing a drip irrigation system to water them more efficiently.

Underwatered plants need to be watered more regularly. Get to know your plants well, and get to know the environment they thrive in. Get a feel for the weight of the growing medium when it’s dry, as well as when it’s saturated.

3- pH Imbalance

Now that you know a little more about pH, it’s important to understand how to adjust it if necessary. For soil growers, adding organic matter (compost, manure, etc.) will help to increase the acidity and bring the pH closer to 6. For hydroponic growers, adding nutrient salts will achieve the same goal.

If the pH is too high, you can lower it by adding vinegar or lemon juice to the water. Be sure to test the pH before adding any acidic substances, as they can quickly lower the pH to a level that is harmful to your plants. If the pH is too low, you can raise it by adding baking soda to the water.


Although you can buy a pH tester online, home kits don’t always test for calcium carbonate – which can make your soil heavy in alkaline materials.

You can check for its presence by adding a soil sample to a cup of vinegar; if it fizzes, there’s calcium carbonate. Alternatively, send a sample off to a testing lab to determine the pH level.

4- Heat Stress

If you’re growing weed, then you know that heat stress is a real issue. It can cause leaves to turn yellow or brown, and in some cases the leaves may even curl up. But why does this happen, and more importantly, what can you do to prevent it?

Well, as with most things, it comes down to science. When the temperature gets too high, the cannabis plant starts to produce more of a certain type of enzyme.

This enzyme is responsible for dissipating heat, but it also causes the plant to produce less chlorophyll. Chlorophyll is what gives plants their green color, so when it’s produced in lower quantities, the leaves start to turn yellow or brown.


If you want to grow your own plants, then you need to know how to use a light source. Make sure the light source is the right distance away from your crop.

You will need to monitor it and change it regularly as the plants grow. You should also invest in a thermometer. If it’s too hot, then add air conditioning or fans.

5- Pests and Insects

If you’re seeing yellow leaves on your marijuana plants, there could be any number of causes. However, one common reason is the infestation of insects.

The specific symptoms will depend on the type of insect responsible. However, fungus gnats are a common culprit in causing chlorosis (a condition where the leaves turn yellow).

These pesky insects are often attracted to overwatered plants, and their larvae can feed on the roots, leading to yellowing of the leaves’


.There are a variety of ways to kill off insects naturally, without the use of harmful chemicals. One popular option is diatomaceous earth, a powder made from the fossilized remains of aquatic creatures called diatoms.

Diatomaceous earth works by scratching and piercing the insects’ exoskeletons, causing them to dehydrate and die.


Marijuana plants can experience yellow leaves for a variety of reasons, some more serious than others. If you see any leaves that are wilted or frail, it’s important to remove them and identify the underlying issue.

In most cases, however, there’s no need to panic if your plants have a few yellow leaves. The leaves may simply be lightening in color as they approach harvest

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