Save 30% on all products💰


left to use your discount!

Cannabis Leaves Turning Yellow – How to Treat and Prevent this Problem

Cannabis Leaves Turning Yellow

Cannabis leaves turning yellow is one of the crop’s most common problems. These events are more than a disease; they indicate that something else, maybe more considerable and severe, is likely to harm the cannabis plant. Yellow spots on cannabis leaves are widespread, and professional growers may already know how to eliminate them.

Major causes of yellow spots on cannabis leaves

Yellow spots on cannabis plants, like any other sickness, originate someplace. These are the most typical causes of yellow spots on cannabis leaves.

pH issues

Choosing the proper pH level for your plants is critical and may make or ruin a home growing operation. This can be as simple as using the wrong type of soil, which can cause significant issues. However, if the pH level is wrong, a condition known as “nutrient lockup” might develop. This chemical process occurs when a plant cannot absorb nutrients from the soil and can permanently harm the plant if action is not done quickly.

How to identify pH issues

The yellowing of the leaves is an unmistakable sign of a pH abnormality. However, further research will be required to be specific. Not only is there discoloration, but there are also areas on the surface and scorching on the margins of the leaves.

How to treat pH issues

Invest in a pH pen or cannabis fertilizers that include pH-perfect solutions and can automatically adapt to a broader pH range. Flush plants with clean water before restarting feeding with a light-dialed-in solution tailored to your growing medium. Generally, pH values between 6.0 and 7.0 for soil and 5.5 and 6.5 for hydro or coco coir give the best habitat for your plants to thrive. Also, ensure that the foundation nutrition you use contains all of the necessary microelements, or you will have to add additional bottles of supplements to your budget.

How to avoid pH issues

Prevention, like therapy of pH imbalance, depends on providing your plants with the greatest possible environment from the start. Check the health of the leaves and test your growth media regularly to avoid pH imbalances and nutrient lockup.

Temperature problems

Providing your cannabis plant with an environment that is too hot or too chilly may produce problems. This may happen inside and outdoors, and it can be caused by anything from leaving a plant in full sunlight for too long to placing it in a chilly location. Fortunately, it is straightforward to avoid or treat.

How to identify temperature problems

The optimal temperature for cannabis might vary depending on the strain and humidity of your area. However, 20-28 °C is the best temperature range for cannabis cultivation. Discolored and twisted leaves will arise from inconsistent or extreme temperatures. An overheated plant can rapidly dry up, leaving the soil dry and the leaves withering. The same is true for constant low temperatures. If you detect these signs on your plants, acting as soon as possible is advisable to fix the situation.

How to treat temperature problems

Indoors, increase the temperature or add extra lights to the grow operation to transform a negative into a bountiful harvest. Outdoor gardeners may need to bring their plants inside at night or invest in a modest DIY greenhouse. Furthermore, indoor growers must switch on the air conditioning and verify that the intake and exhaust fans are powerful enough for the grow room’s size. Outdoors, most farmers can build a modest shade structure and hope the heat is brief.

How to avoid temperature problems

Keep an eye on your grow operation. Place your plants in regions where they will have enough air circulation and will not be subjected to extreme cold or heat. This is frequently enough to prevent any temperature concerns.

Light burn

Indoor cannabis plants cultivated under artificial lighting must be correctly positioned, with lamps placed just above the canopy for the greatest results. When lights and reflectors are too close to the blooming tops, the light is too bright, and the buds and leaves become yellow and brown.

Leaves turning yellow during flowering

This is primarily a top-down issue. In contrast, insufficient light is generally an issue most noticeable from the bottom up. Light shortage causes shaded leaves or leaves too far below the lamp’s light penetration capabilities to yellow and drop off.

How to identify light burns

Yellow leaves will emerge on a plant that has been lightly burned. Yellowing usually begins on the sections of the plant closest to the light source. This excellent visual indicator will help you determine whether the light burns faster. Other signs include yellowed leaves that are difficult to remove.

How to treat light burns

Ensure that you adhere to the manufacturer’s directions while hanging your grow lights. Adjust as the plants grow, and use a tape measure for accuracy. There are so many grow light innovations on the market these days, each with its properties, that you need to follow the manufacturer’s directions to position the light in the perfect spot.

How to avoid light burns

Preventing this condition is as simple as treating a minor burn. Whether you’re an expert home grower or a newbie, take your time to establish an ideal possible environment for your plants and make sure your lights are at a safe distance to avoid harm.

Root rot

Too much moisture due to overwatering can cause much more severe problems, such as root rot. This microbiological disease targets plant roots and causes them to decay if left untreated.

How to identify root rot

Along with the yellowing of the leaves, root rot causes your plant’s roots to turn sticky and brown. You may examine the health of your roots by carefully removing the plant from its container. If the plant has started to decompose, the roots will emit an unpleasant odor.

How to treat root rot

Once root rot has set in, there are numerous ways to fight it. Begin by adding good bacteria into the soil, such as mycorrhizal fungi, to battle the bad ones. Next, review your watering schedule. Reduce watering and add more only until the top inch of soil is fully dry.

How to prevent root rot

Maintaining a regular watering plan will prevent root rot from developing. You may also look into using cloth pots for additional aeration and drainage. This ensures that your plant’s roots are not sitting in damp soil.


Too little or too much water or moisture can cause various symptoms in your plants. It’s no secret that cannabis flourishes in a well-functioning wet-dry cycle. Furthermore, you should be mindful of your watering routine to avoid potential plant issues.

How to identify under/over-watering

Cannabis plants that have been under or overwatered appear remarkably similar. Plants that have been underwatered will have yellowing and wilting leaves due to a lack of water content in their leaves. They will feel nearly frail when touched. Check the plant’s soil and the underside of the container as well. If the soil is arid, your plant will surely want water.

Conversely, overwatering is a comparable scenario. A cannabis plant with too much water will have drooping, curled leaves that feel stiff to the touch. This is because they have so much water in them, causing their structure to bend. Also, the soil might be moist, or your pot could rest in a puddle of water.

How to treat under/over-watering

Keep a close eye on the plant’s post-feeding behavior. Use techniques to determine when to water to prevent a recurrence more precisely. Also, excessive watering might cause root rot. A lack of water will stifle development. Keep a grow diary if necessary, and attempt to establish a schedule as the grow grows.

How to prevent under/over-watering

When it comes to prevention, make sure you maintain your plants regularly, including watering. A simple touch of the soil, digging your finger to your first knuckle, will typically tell you if it’s dry and needs water.

Under/ over-fertilization

Nitrogen, potassium, and phosphorus are the essential nutrients for cannabis. They are critical for plant growth, performance, and general health. They are commonly found in liquid and granular plant fertilizers. However, too much or too little fertilizer can harm any growing effort.

How to identify under/ over-fertilization

Over-fertilization causes curled, yellowed, and crunchy leaves due to nutrient burn induced by too much fertilizer. Also, cannabis plants that haven’t been fertilized will have dried out, yellowed, and wilted leaves, indicating a lack of nutrition.

How to treat under/ over-fertilization

You’ll need to increase your feeding regimen if you have vitamin shortages. Increase the quantity you’re feeding gradually until the symptoms go away. Most store-bought cannabis fertilizers will come with instructions on how to use them and how much you should use, making any over-fertilization concerns easily remedied. Additionally, in situations of over-fertilization, reduce feeding and cleanse the growth medium with clear water; resume feeding according to the product’s recommendations.

The common names for this issues are cannabis deficiencies or nutrient deficiencies. Common cannabis nutrient deficiencies include:

There are more cannabis deficiencies that can cause yellow cannabis leaves and you can find articles regarding them on our site. For accurate diagnosis check out our general deficiencies article and work from there!

How to prevent under/ over-fertilization

Using fertilizers requires patience and verifying that your plants demand additional nutrients. Using them too late or too early in the plant’s life cycle will do more damage than help. So make sure they’re prepared, and you won’t go wrong.

We all desire the utmost for our cannabis plants, and the presence of lush green leaves is a solid sign that your strain is doing well. However, this might be a concern if your leaves begin to turn yellow. Although there are several reasons for this, many fear for plants, but it is happily not the death sentence. You can step in and get your plants back on track in no time with some inventiveness, patience, and observation.

Picture of Taylor Christianson

Taylor Christianson

Taylor is an indoor expert. Through their writing, they offer a masterclass on growing cannabis indoors, maintaining a productive growing environment, and guiding growers through all the stages of growth both indoors and outdoors. Combining multiple fields of expertise allows for Taylor to give in-depth insights into overall cannabis growing. About this Author

Our Experts

Get a Discount

Best Selling Cannabis Seeds

Here's 30% Off On Us!

We want to help you get your hands on the seeds you want, take 30% off your next purchase when you enter your email below!

Here's 20% OFF On Us!

We want to help you get your hands on the seeds you want, take 20% off your next purchase when you enter your email below!