by Nebula Haze
Does your marijuana plant have brown edges, yellow tips, burnt tips, or similar symptoms? This is probably one of the most frustrating grow problems because it can be really hard to pin down the cause. Most pot growers are told they have “nute burn” or nutrient burn. That’s the cause some of the time, but often there’s another problem.
No more wondering! Learn whether you have nutrient burn on your plants, or something else!
Nutrient burn can burn the tips of your leaves, but other problems cause similar symptoms. How can you tell the difference?
Before you start reading this page, ask yourself the following questions:
- Do I have a good growing environment? (Not too hot/cold, gentle breeze, fresh air, etc.)
- Could I be overwatering (or underwatering) my plant?
- Did something different happen right before I starting seeing symptoms (cold night, heat wave, watered plants heavily, foliar spray, new supplement, etc.)?
Keep those answers in mind. Without further ado, here are pictures of common problems, so you can determine what’s causing your burnt tips.
This is Nutrient Burn
Nutrient burn (or “nute burn”) is the result of giving plants more nutrients than they need. The first sign is brown leaf tips. These burnt leaf tips are a sign the plant isn’t able to move water and nutrients properly in the plant. If the nutrients aren’t dialed back, the brown can spread inward from the leaf tips.
Nutrient burn caused brown, burnt tips that will crumble between your fingers.
Nutrient burn may also be accompanied by dark green leaves (the result of too much Nitrogen)
This is Overwatering
Overwatering your plants is common. It’s often a sign you love your plants and want to give it everything. But watering issues can cause a surprising number of symptoms that are often mistaken for something else.
Signs it may be overwatering:
- Plants are droopy some or all of the time
- May look like a nutrient deficiency
- Soil or coco appears dark, muddy, or has patches of green algae
- Top of grow medium never dries out between waterings
- Leaf symptoms often get worse the day after watering
This looks like a nutrient deficiency but the actual cause is overwatering. It’s extra easy to overwater small seedlings in a big container.
Chronic overwatering can cause the edges of leaves to turn brown
This looks a bit like nutrient burn or a nutrient deficiency, but these brown curled tips were caused by giving too much water, too often. New symptoms appeared after each watering. The leaves started growing green and healthy once the grower stopped soaking the soil.
Sometimes overwatering causes brown patches that look like a calcium deficiency. This is because overwatering disrupts the inner processes of the plant, which can trigger a wide variety of symptoms.
This is Light Stress
Even if it’s not hot, marijuana plants can still get stressed out by too much light (for example if the grow light is too close). Sometimes the leaf symptoms appear almost like a sun burn, with the leaves closest to the light appearing bleached. But sometimes the first sign is yellow leaf tips close to the light.
Signs it may be light stress:
- Leaf tips are yellow instead of brown
- Yellow tips appear close to the light (instead of all over the plant)
Light stress can cause yellow leaf tips close to the grow light
This is a more extreme example of light burn
This is a PH or Nutrient Problem
Nutrient deficiencies can also cause burnt or yellow leaf tips and edges. It’s possible for a plant to use up all the nutrients if growing in soil, but I’ve found that most marijuana growers provide nutrients in some form. If you’re still seeing nutrient deficiencies, the likely cause is incorrect pH at the roots. Boring, I know. But pH is the root of a lot of growing problems!
A potassium deficiency causes the edges of leaves to appear burned
A potassium deficiency doesn’t affect tips as evenly as nutrient burn, and creates symptoms further into the leaf
A copper deficiency causes yellow edges and tips on dark leaves
A magnesium deficiency can also make leaf edges yellow or light green
Those symptoms looked different from each other, but they had the same cause: the grower didn’t check the pH of the water before giving it to their plants.
This is Heat Stress
Marijuana plants often start getting stressed out when it gets above 85°F (30°C). Some strains are even more sensitive depending on where they originated from. Learn 5 secrets heat control.
Heat Stress can make leaf edges look burnt
An extreme case of heat stress after experiencing 100°F (38°C) for several days
This is Bugs or Pests
Certain bugs and pests can cause burnt leaf tips or edges. For example, a heavy infestation of fungus gnats (which look like tiny flies buzzing around the soil) can damage the roots and cause symptoms that include brown or burnt leaf edges.
A bad bug infestation can cause a variety of symptoms (look what these fungus gnats did to this poor plant!)
Marijuana leaves with brown, burnt, or yellow tips can be hard to diagnose. Sooooo many problems can cause symptoms that look almost exactly the same. Once you identify the issue, it’s easy to fix. I hope this article helped you figure out the cause of your problem.
Still don’t know?
Check out our plant doctor tool to diagnose your sick plants!
P.S. Remember no plant is perfect so don’t stress over the small stuff. In the end, we’re growing buds, not leaves, and a few discolored leaves won’t hurt anything 🙂
You may enjoy the following articles…
- Why Are Leaves Dry or Crispy?
- The Solution to Yellow Leaves
- What Causes Red Stems?
- Fix Curling or Clawing Leaves (“The Claw”)