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Marijuana Plant Problems And How To Fix Them July 22, 2021

Marijuana Plant Problems and How to Fix Them

Marijuana plants, just like every other type of plant, can suffer from a range of health problems. Marijuana plant problems can be related to many areas of the plant, including:

  • The roots
  • The leaves
  • The buds
  • The flowers
  • The nutrients
  • The light levels

In this guide, we’ll start with a section on identifying marijuana plant problems. After that, we’ll look at troubleshooting marijuana plant problems. Finally, we’ll cover 16 of the most common marijuana plant problems. In that section, we’ll cover both the symptoms and the solutions.

The end goal of the guide will be to inform you about all you need to know to deal with problems before they permanently damage your plants. 

Identifying Marijuana Plant Problems

When you suspect that you’ve got problems with your plants, one of the easiest things to do is look at marijuana plant problems pictures on a search engine. That’s because identifying marijuana plant problems can often be done by looking at the leaves.

They can have smooth edges, bugs on them, be discolored, dead, spotted, moldy, and so on. That makes them the first place to look at. Then what you can do is take pictures or make notes of what’s going on with the leaves and search it up. 

Marijuana Plant Problems

But first, you should have a look through the rest of this guide to see if it’s any of the problems we’ll be listing. 

Troubleshooting Marijuana Plant Problems

Once you’ve used marijuana plant problems pictures to ascertain what’s wrong with your plant, then it’s time to deal with the problem. Marijuana plant problems are generally dealt with using a variety of methods. These include:

  • Adjusting the pH of the roots 
  • Providing different nutrients
  • Observing the leaves for changes 
  • Changing the amount of water 
  • Using suitable insecticides

The specific solution you apply when troubleshooting marijuana plant problems will depend on the problem you have, and there will also be steps to follow.

But so long as you follow those steps, then your problem should clear up in no time.

16 Common Marijuana Plant Problems

Leafhopper Damage on Marijuana Plants
Leafhopper damage on marijuana plants

Leafhopper Damage

They also have a habit of passing on diseases to your plants, so it’s important to remove them as fast as possible. 

To purge your plants of leafhoppers, catch them as soon as you see them, and manually take them off the leaves. You can also use an organic insecticide that won’t harm your plants. Or you can release ladybugs all over your plants, which will eat the leafhoppers.

How to purge your plants of leafhoppers

To purge your plants of leafhoppers, catch them as soon as you see them, and manually take them off the leaves. You can also use an organic insecticide that won’t harm your plants. Or you can release ladybugs all over your plants, which will eat the leafhoppers.

Copper Deficiency in marijuana plants
Copper deficiency in marijuana plants

Copper Deficiency Plant Problems

How to fix copper deficiency in marijuana plants

The affected leaves may remain yellow, but the priority is to stop the spread. To do that, you’ll want to change the root pH. You can do it by flushing your plant with water that’s got the right pH, and by giving your plant good nutrients.

Calcium Deficiency in marijuana
Calcium deficiency in marijuana plants

Calcium Deficiency

If your plant is suffering from a calcium deficiency, then you’ll need to look at your leaves closely to confirm it.

They should have little brown spots all over them. It can be helpful to use LEDs because this deficiency will look different depending on the strain that you have. 

To solve calcium deficiency in marijuana plants, you’ll need to adjust the pH in the roots.

The wrong pH will make it difficult for your plant to absorb calcium, which will have caused this problem. But you can also use a supplement with additional calcium.

Broad Mites on marijuana plants
Broad Mites damaging marijuana plants
Marijuana Plant Problems

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Broad Mites

A particularly dangerous problem is broad mites. These are invisible to the human eye, so you will only see the damage they cause once they’ve caused it. That damage includes blistering to the leaves and twisted tops.

Fix broad mites on marijuana plants

You can easily confuse this with deficiency problems, so make sure to look carefully. To deal with this, you’ll have to cut off the parts of the plant that have the symptoms, as they can’t be saved. You’ll then have to treat the plant multiple times a week using organic pesticides or oils. When the infestation is cured, keep treating them for another 5 weeks.

Marijuana plants nitrogen toxicity
Marijuana plants nitrogen toxicity problem

Nitrogen Toxicity

Sometimes a marijuana plant can suffer from poisoning due to a mineral imbalance, rather than the more typical deficiency problems. When that toxicity comes from nitrogen, your plant will seem sluggish. It will grow slowly, have weak stems, and leaves that seem to shine.

Fix nitrogen toxicity on marijuana plants

They can sometimes curve as well, and this is a unique symptom. If it’s not treated, those leaves will discolor and eventually die. Usually, too much nitrogen has been given, so the answer is to give your plants less! If you’re giving your plants any extra nitrogen, stop doing that. If you’re not, then you’ll still need to reduce the nitrogen dosage.

Under Watering Problem in Marijuana
Under-Watering Marijuana Plants

Under-watering Marijuana Plants Problem

If you’ve been busy or otherwise occupied during warm weather, then you may not have given your plants enough water. This is a common problem, and you can spot it by seeing if the leaves are wilting or feel like paper. If you leave this problem too long, it can develop into nutrient deficiencies.

How not to under water marijuana plants

If you have a schedule where you give certain amounts of water, then you’ll probably need to adjust it. You can test giving more water, and then see if the leaves improve. That will show you that underwatering was indeed the problem.

Iron Deficiency In Marijuana
Iron deficiency in marijuana plants

Iron Deficiency

Another type of deficiency you might notice in your marijuana plants is iron deficiency. Like the others we’ve covered, it’s most commonly caused by a pH imbalance, but not always. Sometimes it can be caused by a stressful environment.

Your plant leaves will go very yellow but can turn green again. That’s how you know it’s an iron deficiency.

Solve iron deficiency in marijuana plants

To fix iron deficiency, you’ll want to adjust the pH to a lower level, as high pH stops the roots from absorbing iron. You can also use higher-quality soil, or provide your plants with additional nutrients.

heat stress on marijuana plants
Heat stress on marijuana plants

Heat Stress

Despite the well-known reputation of cannabis plants for demanding heat and light, there is such a thing as too much heat. If this happens, you’ll notice that the leaves on your plants will begin to show spots and burns. They might also curl or fold inwards. This happens both indoors and outdoors.

How to avoid heat stress on marijuana plants

To avoid this problem, or solve it if it’s already happened, then you’ll need to monitor temperatures closely. Once you’ve implemented that, then you can control the temperatures using ventilation indoors or shade outdoors. Indoors, you can change the position of the growth lights.

 Mealybugs on marijuana plants
Mealybugs damaging marijuana plants


One of the most easily spotted marijuana plant problems is mealybugs. These bugs are hairy and white, which makes them stand out immediately if they’re on any of your plants.

They like hot temperatures, and can even spread after harvesting is complete. They leave trails of white powder behind them too.

How to keep mealybugs away from marijuana plants

To expel mealybugs from your marijuana plants, you’ll need to apply water spray to throw them off the leaves. After that, you can use oils and soaps. You can use more than one, and it may take a few attempts for it to be effective. But you should only use one substance each day.

Molybdenum Deficiency in Marijuana
Molybdenum deficiency in marijuana plants

Molybdenum Deficiency

This deficiency has interesting symptoms, which is why we’ve included it here. The leaves on your plant will change into shades of red and pink at the edges. They can also develop spots. Occasionally, those colors start in the center of the leaves. It is a slightly less common problem, but still worth addressing. 

How to fix molybdenum deficiency in marijuana plants

To solve it, you should raise the pH levels of the cannabis roots. That’s what prevents molybdenum from being taken up. Once you’ve done this, no more leaves will change color, but existing leaves will remain pink or red. 

Whiteflies damaging marijuana plants
Whiteflies damaging marijuana plants


Whiteflies share the same color as mealybugs, but they’re smaller and don’t leave trails behind them. The closest way to identify them is to think of moths.

They will hide underneath the leaves and steal the nutrients you’re giving your plants. Eventually, this will lead to white spots showing up on the leaves.

How to keep whiteflies away from marijuana plants

You’ll need to address whiteflies rapidly because if you don’t they can lay eggs on the plant which are extremely difficult to remove. Luckily, there are a few solutions. You can use salts from fatty acids, and insecticidal soaps. They’ll weaken the flies.

Thrips damaging marijuana leaves
Thrip damaging marijuana leaves


An intriguing name for an insect, but thrips are deadly. They use their mouths to puncture cannabis leaves and suck away all the nutrients. If your leaves have been invaded by thrips, you’ll notice spots of bronze or silver. The longer the thrips are around, the higher the chance your leaves will die.

How to keep thrips off your marijuana plants

Using oil is a good choice when it comes to remedies. It will repel the bugs and stop them from returning, and you can simply spray it across all your leaves. You can also use various types of insecticide depending on your preferences.

Spider damaging marijuana leaves
Spider damaging marijuana leaves

Spider Mites on Weed

Spider mites are a challenge to remove once they’ve established themselves. It may take a while to spot them as they’re very small and tend to hide on the backs of leaves.

Like thrips, they steal nutrients from the leaves of your plants. They’re also common, no matter where you’re growing your cannabis.

How to keep spiders off your marijuana plants

To remove them, you have to start by killing them as fast as possible. Spray the plants, blow a lot of air on them, and keep the temperatures under control. After that, start using insecticides to kill any mites that remain.

Marijuana Root Rot Problem
Marijuana Root Rot Problem

Root Rot

Root rot is a tricky problem to solve because it involves the roots when grown hydroponically. Normal cannabis roots are white and stringy. When they rot, they turn to mush, wrap together, and feel slimy.

The causes of root rot are pathogenic substances inside your grow medium or a lack of oxygen reaching the plants.

How to fix root rot in marijuana plants

Fixing root rot involves treating the roots themselves and changing the environment so the root rot doesn’t continue. You can add special bacteria to the roots that will fight off any diseases that have infected the roots, and add an air pump to your hydroponics.

Wind Burn on marijuana plants
Wind Burn on marijuana leaves

Wind Burn

Although marijuana plants need a lot of ventilation, and air has to circulate through grow rooms, there can be too much of it. If your plants are suffering from windburn, they’ll have spots on their leaves. The leaves may also be clawed.

You can verify that your problem is wind-burn by comparing leaves at different distances from your fans. 

How to avoid wind burn

To ensure windburn doesn’t happen to your plants, or to fix it if it has, reposition the fans so that they’re not too close to the leaves, and make sure the breeze in the room isn’t too heavy. 

Light stress on marijuana plants
Light stress on marijuana plants

Light Stress

We looked at heat stress earlier, and a similar problem is light stress. Just as your plants can have too much heat, they can also have too much light. If that’s the case, the leaves on your plant will begin to turn yellow.

You can spot it by looking at leaves closest to your grow lights and seeing if they’re the yellow ones.

How to fix light stress on marijuana plants

you can simply move your grow lights away from the plant and ensure that no leaves are touching them. It’s best to make these changes gradually, so you can see how your plants respond. 


In this guide, we’ve covered 4 areas: 

  • Common marijuana plant problems
  • The need to look at marijuana plant problems pictures
  • Identifying marijuana plant problems
  • Troubleshooting marijuana plant problems

If you want to avoid as many of these problems as possible, you should buy the I Love Growing Marijuana Plant Protector Set. It will repel a wide range of diseases and bugs quickly and effectively.

Marijuana Plant Problems

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