Yellow Spots on Weed Plant Leaves: Causes and Treatment

Why Are There Yellow Spots on Weed?

When growing cannabis, yellow leaves are a sign that something is wrong. If your plant happened to turn yellow, you’d want to take action immediately.

Otherwise, it could jeopardize your entire harvest. Fortunately, as long as you catch it early, treating these conditions isn’t all that complicated. However, before you can do anything, you must identify the cause. If not, then you’ll only treat the symptoms.

Yellow Leaves On Marijuana Plant
Yellow Leaves On Marijuana Plant

Yellowing Leaves Can Be Caused by a Variety of Factors

So, while you were growing your crop, you noticed a few of the leaves had begun to turn yellow. Without any other information, you understand something is wrong. However, you aren’t quite sure what it is.

Well, if you are growing and noticed something like this, it could be any of the following reasons. When you notice yellowing leaves, work through this list. Typically, you’ll find the answer.

Common Causes of Yellow Leaves

1) Leaf Septoria

Above all, this would be the most common cause of yellowing leaves. Occasionally, cannabis plants provide a wonderful host for fungi. These fungi colonize the leaves. Then, you’ll notice the leaves turn yellow. If you leave the fungi alone for long enough, the leaves will turn brown. Eventually, they may even fall off the plant.

2) Nutritional Deficiencies:

Cannabis requires many nutrients. Unless it has all of them, it won’t be healthy. Sometimes, even though you fertilize it, they won’t absorb everything. If that happens, you may notice some discoloration among the leaves. Usually, it won’t be quite as severe as it could have been. For the most part, nutritional deficiencies are easy to cure.

3) Inadequate Light:

Of course, all plants need sufficient light. Without that, photosynthesis is impossible. When plants are starved of light, they begin to wilt. Among the first signs would be yellow leaves.

4) Inappropriate Water:

Besides light, all plants also need water. When they don’t receive enough of it, they grow weaker. Above all, you’ll notice the wilted leaves. On the other hand, if they have excess water, it can also cause problems.

Leaf Septoria
Leaf Septoria

How to Treat Leaf Septoria

Let’s say a few of the leaves have begun to turn yellow on your cannabis plant. So, you decide to investigate further. While examining the leaves, you noticed something peculiar. All spots are uniform. Plus, it seems as if the leaves have a pimple. If you notice something like this, then you’ll know that it is leaf septoria.

Usually, Caused by a Bacteria or Fungus:

These are infections of the leaves. Most of the time, it’s the result of a fungus. However, on some occasions, it could also be from bacteria. Regardless, at the end of the day, the effect is the same. Your beautiful cannabis plants begin to turn yellow.

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Tends to Start Towards the Bottom of the Plant:

For further confirmation, you can look at the progression. When the leaves near the bottom turn yellow first, that’s another strong sign. Since infections tend to start near the bottom of the plant, you’ll notice signs there in the beginning.

Treating Marijuana Plants
Treating Marijuana Plants

Treatment Methods

1) Prune All Affected Leaves:

When you notice yellow spots on weed, grab your pruning shears. Once you have those, chop off all the affected leaves. Of course, you might not want to do such a thing. However, by leaving them alone, the infection will spread. Then, you’ll have to remove even more leaves in the end. By removing the affected leaves, you protect the rest of the plant. Regardless of how much you remove, you’ll have a better harvest. If you don’t remove those leaves, the infection could dominate the entire plant. At that point, you might even lose the whole thing.

2) Minimize Moisture:

Once the leaves are pruned, dry the plant. That said, don’t remove all the moisture. If that happened, then the plants would die. Nevertheless, excess moisture promotes the growth of such fungal infections. By minimizing the humidity, you’ll lower the likelihood of this occurring.

3) Apply a Fungicide:

Traditionally, fungicides should be applied before an infection occurs. While they are effective at killing fungal infections, they are even more effective at preventing them. So, to provide the best protection, apply the fungicides early. That way, even if fungus tries to colonize the leaves, they won’t stand a chance.

4) Ensure the Plants Are Healthy:

With all that said, we should mention something rather obvious. The healthier the plant is, the more resilient it will be. Thus, by raising a healthy crop, they will be resistant to infections. Therefore, you’ll see fewer of them. If you can raise your plants as healthily as possible, you will have far fewer issues.

Nutritional Deficiencies In Marijuana
Nutritional Deficiencies In Marijuana

Preventing Nutritional Deficiencies

Besides those infections, nutritional deficiencies can also cause your leaves to turn yellow. Typically, your plans receive all the nutrients they need from the fertilizer. However, even when you fertilize them, there are no guarantees. Sometimes, you’ll still have a few deficiencies. In those circumstances, check the following list. These are among the most common deficiencies encountered in cannabis plants.

Common Nutritional Deficiencies

1) Phosphorus:

Although these deficiencies are rare, they are easily identifiable. When plants like phosphorus, their leaves turn purple. If you notice something like that, you’ll know what to do. By giving the plants more phosphorus, you should notice the colors return.

2) Nitrogen:

When your plants don’t have sufficient nitrogen, they start to lose their color. If you notice something like that, add some nitrogen to their soil. That way, those colors will return.

3) Potassium:

Most of the time, you’ll find potassium deficiencies in plants with excess nitrogen. Thus, to prevent this deficiency, give the plants less nitrogen. That way, they can absorb everything from the soil.

4) Magnesium:

With magnesium deficiencies, the leaves turn yellow while the veins remained dark. When that occurs, give the plants more magnesium.

5) Sulfur:

Sulfur deficiencies look similar to the others. However, you’ll notice the effects on the newest leaves first. To add more sulfur to the soil, try throwing a bit of Epsom salts on it.

Bud Rot In Marijuana
Bud Rot In Marijuana

How to Prevent Bud Rot

Finally, if your leaves begin to turn yellow, it could be a sign of the bud right. This would be another condition caused by fungal infections. However, instead of infecting the leaves, these tend to infect the buds. For that reason, cannabis growers find them to be even more threatening. Luckily, by using the advice below, you should have an issue with it. That way, once it is time to harvest, you’ll be blessed with abundance.

1) Good Ventilation:

Usually, you’ll have these issues in areas with poor ventilation. If there isn’t enough airflow, things can settle on the leaves. When there is sufficient airflow, such spores don’t have a chance to grab hold. Instead, they will be blown away before they can take root.

2) Low Humidity:

Above all, controlling the humidity is crucial. Otherwise, in humid environments, fungal growth is prolific. Fortunately, by providing ventilation, you’ll also minimize the humidity. As the fans below, humid air flows away. Without enough moisture in the air, the fungus doesn’t have everything necessary to grow. Thus, by growing in arid environments, you will avoid such infections.

3) Plenty of Nutrients:

Finally, for the healthiest plants, Provide them with sufficient nutrients. The healthier your plans are, the less likely infections will be. Even if something lands on the plant, as long as it’s healthy, it can fight off the infection. However, if there are deficiencies, then the opposite might occur. At that point, you’ll have an even larger problem on your hands.

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