The trademark marijuana leaf is known all over the world as it represents weed users, their appreciation of marijuana as a recreational and medicinal drug. And it is through the leaves that you can tell so much about a cannabis plant. You can easily tell if a plant is suffering from nutritional problems, watering concerns, and temperature and humidity problems when you check its leaves. Here are the most common cannabis leaf problems to help you understand your cannabis plants better.
1. Blue-green and brown blotches
Finding blue-green and brown spots on your plants can be a terrifying thing. Usually, this means that your plants are lacking phosphorus. This major nutrient is crucial for root and stem development. It is also essential during the flowering stage as it works hand in hand with potassium to boost bud growth and improve yields.
Blue-green and brown spots that are found on the lower leaves indicate a lack of phosphorus. Aside from this discoloration, the leaves may also look thick and dry. Sometimes leaves may look shiny and may fall off from the plant when phosphorus deficiency is overlooked.
To fix these problems, flush your system with clean and pH-balanced water. Doing so will flush out all salts that may have crystallized in soil or the roots. These usually affect the uptake of many nutrients including potassium and phosphorus. You may also use products with high phosphorus levels like crab shells, fish meal, bone or blood meal, worm castings, and soft rock phosphate
2. Brown spots or rusty spots on the surface
Brown spots on the leaves or spots that resemble rust are calcium deficiency. Calcium is needed by plants for structure and to protect it from warm temperatures and other stressors. In calcium deficiency, the new upper leaves are affected first and the lower leaves will curl. The brown spots have random shapes and sizes and may appear intensely or in faded color.
Treatment for calcium deficiency is to first check pH levels. The best pH for calcium absorption in the roots is from 6.2 to 6.4. If the pH of your soil is off, rinse it with clean, pH-balanced water. And afterward, feed your plant food rich in iron, calcium, and magnesium.
3. Burnt tips
Burnt tips or yellow tips are due to nutrient burn. This is common in plants that are receiving very strong nutrients or when nutrients are given more often than recommended. When this is overlooked, the leaves will become brown and very dry.
When the nutrient burn is overlooked, the leaves will continue to dry up and lose mass. Also, your buds will develop an unpleasant taste and smell. To fix this common cannabis leaf problem, stop giving nutrients for 7 to 14 days. This will help flush out excess nutrients.
4. Drooping leaves
Drooping is due to overwatering or watering your plants more often. The leaves appear firm and are curled downwards. To fix overwatering, wait until your plants have absorbed water before you water again. The best time to water your plants is during the early morning as it is not yet too hot.
5. Mildew or white powdery mildew
Cannabis plants with WPM or white powdering mildew are due to mold that covers the leaves, stems, and even the buds. WPM is fuzzy white patches all over the leaves and when this is overlooked, mildew can spread all over the plant and may lead to wilting and even, death.
To treat white powdery mildew, remove all affected leaves. You may also apply natural fungicide on the affected leaves but never on the buds.
6. Pests
Several types of pests can plague cannabis plants. Some pests are winged, some simply crawl around while some are persistent and can latch on the leaves to suck up all the plant juices. You can easily see pests crawling all over the leaves. Remove pests by using friendly pests like ladybugs. Use natural pesticides; follow the steps on how to use specific pesticides.
7. Small and thin, yellowing new leaves
When you spot new leaves that are small, thin, and yellow, then you may have a Zinc deficiency. This element is needed by plants to survive in colder temperatures and is necessary for the digestion of carbohydrates. Zinc deficiency is mostly due to stress and may clear up without treatment.
To help plants recover faster, dry them out, and flush the soil with safe and pH-neutral water. Use tap water only as heavily-filtered water contains high amounts of zinc.
8. Yellow lower or older leaves
If you spot yellowing of the older leaves during the vegetative or flowering stage then you might have a nitrogen deficiency. Nitrogen is a very important nutrient needed for proper plant growth and development. Cannabis plants require more nitrogen during the vegetative phase but not too much during the flowering phase as your plants have ceased to grow during this phase.
If you spot nitrogen problems, discontinue your plant food and flush the system with clean, pH-balanced water.
9. Yellow tips that are curling upwards
Yellow tips that are curling up is due to light burn. Indeed, light is life for cannabis plants but too much can do a lot of harm. So, check if the light source is very near the plant. Also, switch to a less intense bulb. If your grow lights are adjustable, move this farther away from your plants. The yellow curling tips won’t return to their normal appearance but this won’t progress either.
10. Yellowing on the outside of the veins
This type of cannabis leaf problem is due to iron deficiency. Too much iron can affect plant growth as it can slow it down and produce thin buds.
If this is not treated, the leaves will start to look burnt at the tips. As time passes by, the leaves will fall off.
To correct this nutrient problem, dry the plants out and then, water it with pH-balanced and safe water. Adjust the pH to help the roots absorb more iron.
These common cannabis leaf problems are preventable but can be tricky to treat. Avoid cannabis problems by staying diligent and safe.
