What Causes Brown Spots on Cannabis Leaves?

Brown spots on cannabis leaves are a pain in the neck for home growers… the bane of backyard cannabis farmers! Brown or bronze markings on leaves are quite typical signs of marijuana growth. Fortunately, it is usually straightforward and quick to correct once you’ve identified the underlying cause.

Because many cannabis plant disorders may produce similar symptoms, diagnosing brown leaves might be tough. Get the details now. These brown spots were caused by too much heat and light.

You’re not alone if you’ve been dissatisfied with this problem. The first large cannabis growing issue I ever had was scorched brown spots on leaves. For almost a year, I suffered from Issue #2 on this list before discovering the surprisingly simple solution. Since 2008, I’ve had practically every problem on this list, and after a while, I realized how to fix them. Now my plants thrive and are healthy all the time, and I’d want that for your plants as well.

Until now, I’ve never seen someone compile a list of the most common causes and solutions to brown spots on cannabis leaves in a tutorial, so I’ve put it all together for you. When I started growing marijuana, this list of issues and solutions with photos helped me as much as it may help you now.

PH Imbalance

If you notice anything wrong with your cannabis plants, the first thing to look for is the pH level. This is one of the most frequent causes of leaf issues and/or death due to incorrect pH.

Deficiencies caused by nutritional problems, in some cases, can be due to an incorrect pH that is preventing the plants from absorbing what they require. While it is most common in hydroponic gardens, it can also occur in soil gardens. The plant’s stress resulting from erratic pH may cause brown spots to form on its leaves.

Overwatering Or Undewatering

Water intake is one of the most important reasons for leaf discoloration and death. Both overwatering and underwatering can have a detrimental influence on your garden.

Overwatering kills the roots and can lead to root rot, which will swiftly kill your plant as the roots are no longer functional and capable of absorbing water or nutrients. This might be induced by watering too much or too frequently in some circumstances.

Overwatering cannabis plants is generally droopy with curled down leaves. In addition, the leaves may be yellowing or exhibit other indications of nutritional deficiency. Plants require water to live; if they don’t have enough, their leaves will be thinner and appear “lifeless.” Under-watering can also cause yellowing leaves and nutrient shortages.

Cannabis plants require a significant quantity of water, yet the quantity of water retained by the soil, the growing stage, plant size, and other factors will determine precisely what is necessary for that specific plant.

Nitrogen Deficiency in a Cannabis Plant

The later stages of nitrogen deprivation; lower leaves have started to fall away, and even upper layers of leaves are pale yellow Nitrogen deficiency is the most common problem encountered by cannabis growers. It’s typically simple to detect and address once it becomes obvious, although it has a similar appearance to other problems in the early phases.

In the early stages of nitrogen deprivation, leaves appear to be too bright in color—almost yellowish-green—compared to healthy leaves’ normal deep green. Nitrogen-deficient leaves also generally have slightly darker veins than very light leaf tissue, although the difference is not as apparent as in some other deficiencies.

Nitrogen toxicity causes leaves to become intensely green in color, which can look almost black in severe situations. In severe cases of nitrogen shortage, the leaves appear lighter and lighter in color over time, and they eventually start to dry out and die. The upper and outer leaves of the plant are frequently the first to be impacted and destroyed.

Phosphorus Deficiency in a Cannabis Plant

Leaves with severely phosphorus-deficient, indicating purple-brown necrotic leaf spots. Phosphorus shortages are unusual, but they should be cause for concern. It can lead to slower growth rates, smaller leaves, weak roots, and plants that are lethargic in the vegetative stage if it affects plants in the vegetative phase. In general, phosphorus deficiency causes leaves to appear dark but washed out with very dark veins and somewhat lighter leaf tissue in the early phases.

As a result of the disease’s spread, purplish discolourations appear on the main part of the leaves and the leaf edges curl downwards. The leaf petioles (the small stalk that connects the leaf to the main stem) may also become purple. Large areas of leaves turn bright purplish-brown and fall off in later stages, while remaining leaves become speckled yellowish-green.

The lower, outer leaves are frequently the first to be damaged by phosphorus shortages. However, unlike nitrogen deficiency, any stage of phosphorus deprivation is cause for concern because the plants continue to require high quantities of phosphorus during the flowering period.