If you’ve noticed your cannabis leaves curling up, then you’re probably not alone. There are a lot of stresses, pests, and diseases that can affect your marijuana plants. Getting them back into a healthy state is usually possible, but you need to know what’s causing the problem and how to solve it.
That’s what we’ve written this guide to show you. We’ll cover six common causes behind cannabis plant leaves curling up, and share solutions for each one. Then we’ll show you a selection of hardy marijuana strains that are more resistant to pests, diseases, and stresses.
6 Common Causes Behind Cannabis Leaves Curling Up
The six causes behind your cannabis leaves yellowing and curling up are as follows:
- Excess heat or cold
- Overwatering or underwatering
- Excess nutrients
- Wind burn
- Light burn
- Pests
Excess Heat or Cold
If you notice your cannabis leaves yellowing and curling up then that will be because of excess heat. Yellow and brown discoloration only happens with too much heat. When your leaves are too cold, then they’ll curl up too, but you’ll likely end up with a case of bud rot as well, which can be a disaster for your plants.
To solve these problems, you should make sure the temperature of your grow room is suitable for the strains you’ve got and the stage of growth those strains are at. If it’s too cold, add more lights, slow down ventilation, and add more reflective materials. If it’s too hot, move your plants away from grow lights, and increase the ventilation.
Overwatering or Underwatering
Another cause of cannabis leaves curling up on edges is when you give them too much or too little water. The most common of the two is overwatering. If you live in a warm climate or have a hot grow room, then you’ll be focused on ensuring your plants are hydrated. That makes it easy to overdo it.
If you give your plant too much water, it can rot the roots and even drown the plant. If you give it too little water, it can dry out. To solve this problem, do a finger test of the soil. If it’s very sticky and wet, you’re giving the plants too much water. If it’s completely dry, you’re underwatering them.
Excess Nutrients
Even if your plant has enough water and the right temperatures, you can still cause it to suffer. If you notice cannabis plant leaves curling up in this situation, you may have given your plant too many nutrients. Often, this means excess nitrogen.
That can mean cannabis leaves yellowing and curling up because nitrogen causes discoloration. To solve this issue, you should dilute your nutrients using water, and reduce the amount of them. You can even stop providing nutrients for a few days.
Wind Burn
If you have sufficient ventilation in your grow room, then you’ll need to ensure it’s not being overused. If you begin to notice your cannabis leaves curling up on edges, that’s a sign of wind burn. It happens when there is too much of a breeze in the grow room due to excess circulating air.
To address a problem like this, you should lower the speed of your fan, and reduce the strength of the ventilation system. You should also point the fan away from the plants and at the wall. You can also try moving the plants to different parts of your grow room.
Light Burn
If wind burn isn’t the cause of your cannabis leaves curling up, then another possibility is light burn. It usually starts at the top of your plants, and the closer your plants are to the light, the worse the burn will be. Plants do need light, but only so much of it. Lights that are too strong will result in your cannabis plant leaves curling up.
To stop the light burn, you should try changing the lights you are using to some that are less bright. This will have the added benefit of saving you some electricity costs. You can also remove some of the reflective materials on the walls of your grow room.
Pests
If none of the other problems we’ve covered get to the bottom of the issue with your marijuana plants, then the most likely remaining answer is pests. They often cause a lot of other issues for your plants, and that’s why you’ll notice cannabis leaves curling up. Pests include spider mites and fungus gnats.
Often, the only viable solutions are chopping off parts of your plant or using an organic pesticide.
3 Tough Marijuana Strains
Blue Cheese Strain
The Blue Cheese strain is indica-dominant, helping to relax your body and take away pain. It also resists mold, pests, and water-related problems. It’s also good at growing in small areas. At the same time, it gives high yields and doesn’t take long to flower.
Blue Cheese Feminized Seed Properties
| Plant Type | 80% Indica 20% Sativa |
| THC | Up to 19% |
| CBD | Insignificant amount |
| Grow Difficulty | Easy |
| Climate | Indoors | Continental | Mold Resistant |
| Plant Size | Average |
| Flowering Time | 8 weeks |
| Yields | 5 to 9 oz per 3x3ft |
Buy Blue Cheese Feminized Seeds
- 80% Indica 20% Sativa
- THC levels up to 19%
- Fast-flowering grow in- and outdoors
Blue Dream Strain
The Blue Dream cannabis strain is one of the most well-known in the world. It’s resistant to some cannabis diseases like mildew and root rot. Like Blue Cheese, it also yields a lot and flowers in a short time. It’s a sativa-dominant strain that’s good for daytime use.
Blue Dream Feminized Seed Properties
| Plant Type | 20% Indica 80% Sativa |
| THC | Up to 21% |
| CBD | Up to 2% |
| Grow Difficulty | Moderate |
| Climate | Indoors | Temperate | Mediterranean |
| Plant Size | Tall |
| Flowering Time | 9 weeks |
| Yields | 21 oz per 3x3ft |
Buy Blue Dream Feminized Seeds
- 20% Indica 80% Sativa
- THC levels up to 21%
- Consistent heavy yields
Northern Lights
A strain known for its potency, Northern Lights is easier to grow because it doesn’t smell as strong. It’s also known for being a hardy strain, and it will flower within 9 weeks. It’s 90% indica and known for its spicy taste.
Northern Lights Feminized Seed Properties
| Plant Type | 90% Indica 10% Sativa |
| THC | 18% |
| CBD | Insignificant amount |
| Grow Difficulty | Easy |
| Climate | Indoors | Steppe | Mediterranean | Mold Resistant |
| Plant Size | Average |
| Flowering Time | 9 weeks |
| Yields | 12-16 oz per 3x3ft |
Buy Northern Lights Feminized Seeds
- 90% Indica 10% Sativa
- THC levels up to 18%
- Best indoors and in sunny climates
Conclusion
You should now be aware of the main causes for why you’ll see cannabis leaves curling up on your plants, as well as the solutions that you can use to make your plants healthy again. You’ll also know about a few hardy cannabis strains you can look into. Cannabis leaves curling up on edges will be less likely with these strains.
If you’d like to find out more about marijuana strains, then there is one place you can go that’s better than all the alternatives.