Brown tips on cannabis leaves are a warning sign. The tips are the part of the leaf furthest from the source of water and nutrients. This makes them the first to show stress. When brown tips appear, your plant is telling you that something in its environment is not right.
Healthy leaves look smooth and solid green. Brown tips stand out because they mean the roots, soil, water, or air are causing stress for the plant. Your job is to figure out the cause and help the plant recover.
Here are what could be causing the brown tips on cannabis leaves in your grow:
Table of Contents
Nutrient Burn
The most common reason for brown tips on cannabis leaves is nutrient burn. This happens when you use too much fertilizer. Extra nutrients, especially salts, build up in the soil. The plant cannot use this much food. The salts pull water out of the leaf cells and damage the tips.
Once the tips burn, you cannot restore them, but you can keep the problem from getting worse. Use less fertilizer right away. Give your plant plain water for a week. Allow water to drain out of the bottom of the pot to wash away extra salts. This process is known as flushing and will save your plants from nutrient burn.
Here is a detailed help for nutrient burn.
Nutrient Deficiency
Brown tips sometimes come from not enough of a key mineral, such as potassium, calcium, or magnesium. When a cannabis plant cannot take up certain nutrients, either due to unbalanced soil or problems in watering, the tips and edges of the leaves suffer.
A shortage of potassium can leave leaf tips rusty brown while edges turn yellow.
Calcium deficiency can show as small brown patches or marks at the tips. Magnesium issues often appear as yellowing between leaf veins with some brown areas.
Soil pH is important here. If it slides outside the ideal range of 6 to 7, the plant cannot absorb nutrients well. Check your pH with strips or a cheap meter. Adjust if needed and keep it steady.
Read more about nutrient imbalance at weedmania420.com’s deficiency guide.
Light Burn
Brown tips can result from grow lights being too close to the canopy.
The plant tissue cannot cool itself, and the tips dry from heat and intense light. Most often, you will see the problem on the leaves under the brightest parts of your lamps.
Move the lights further away and wait a few days. If the problem stops, you know the light intensity was too high. Leafly’s guide explains how to check for light burn and remedy it.
Watering Mistakes
How and when you water your plant makes a big difference. Brown tips and edges can mean overwatering or underwatering. Overwatering leaves the roots soaked and starved for air. Underwatering dries the plant and makes the tips crack and curl.
Water only when the top inch of your soil feels dry. If growing in coco or a hydroponic system, keep a steady cycle of wet and dry rather than always soaked.
Leaving the plants soaked all the time invites problems like poor aeration and root rot. Keep a regular watering schedule, making sure the plants are neither starved nor overwatered.
Salt Buildup and pH Problems
Feeding your plant often can leave behind salts in the soil. This buildup blocks roots from drawing water and nutrients. This’s why adding nutrients without diagnosing the real problem can further hurt your plant.
Incorrect pH can make these problems worse by “locking out” key minerals, even if they are present.
If you suspect this, flush the soil with lots of fresh, balanced water. In hydroponics, replace the entire nutrient solution for a fresh start.
Once the excess nutrients are flushed and the pH is balanced, your plants will blossom once again, and you’ll be able to resume your regular nutrient regimen.
Disease and Airflow Issues
Sometimes the brown tip on the cannabis leaf is caused by root disease or lack of air movement. This will make your plant weak and disease prone. Once root rot begins, the plant cannot feed the plant well. Root rot is a serious issue that will stagnate the plant’s growth, even kill it if you don’t find the remedy in good time.
Give your plant clean air and space to help leaves evaporate water. Trim away affected growth and space out plants to prevent the spread of disease. A dense canopy holds in moisture and invites trouble.
Wind Burn
If you use a fan that blows hard, it can dry the leaf tips and cause them to turn brown. Make sure air moves gently across your plants, not directly at any one spot. The plant needs a gentle breeze, not a furious wind that dried it out.
Diagnosing the Problem
If only the tips turn brown, you likely see mild nutrient stress or light burn. If brown edges spread down the leaf or affect new growth, the problem is growing worse. If you act fast, your plant can recover. Watch new leaves for signs of recovery.
Steps to Prevent Brown Tips
Start with less fertilizer and raise levels only when growth is slow. Test the pH of your water and soil weekly.
Let your growing medium dry before watering again. Keep your lights at a safe distance. Flush the medium regularly to prevent salt buildup. Stay patient and make changes one at a time.
When Brown Tips Are Not a Problem
Sometimes the brown tips are natural, and there’s nothing you should do about them. For instance, older leaves at the base of the plant often fade as the plant grows and uses their nutrients.
A few brown tips on old leaves is not a reason for worry; it’s natural for them to discolor and drop as the plant grows.
Focus on the health of new leaves at the top.
Recovery and Next Steps
After you make changes, wait a week. New leaves should be green and free from brown on the tips. Old tips will not heal, but your plant will push out fresh growth.
If your plant keeps showing problems, review each area again. Tweak only one thing at a time for best results.
More Help and Resources
You can get the step-by-step guide on how to grow weed, created from over 35 years of experience. The guide addresses all the problems you might run into and offers remedies in easy-to-follow tutorials and diagrams and live images from a real garden. With it, you’ve got everything figured out, and your grow op will be give you a successful run from seed to harvest.
Brown tips serve as warning flags. If you remain calm and address feeding, light, water, and air, your plants can bounce back and produce healthy yields. Take it one step at a time and soon you’ll see green growth return.