You have looked after your marijuana plants, and you watered them on time; yet, you see yellow cannabis leaves. You give them your best, but your cannabis plants do not look healthy the way they should be. Your cannabis plant shows stress through their yellow cannabis leaves despite giving them your time, love, and attention. Unfortunately, not all growers and cultivators grow trouble-free cannabis plants.
Almost every time, yellow cannabis leaves induce fright in cannabis cultivators. The perpetrators of this phenomenon are often various reasons. It could be the side effects of your flushing process, burning, nutrient deficiency, or invasive microorganisms.
Growers and cultivators are usually the ones who frequently fix the problems with just a few changes in their growing process. With years of experience, growers don’t view yellow cannabis leaves as trouble. Instead, they see them as a form of communication as your cannabis plant doesn’t speak human language. With careful observation, you can understand what they are telling you.
Yellow cannabis leaves or its technical name, the chlorosis, is caused by the low chlorophyll in the leaves.
Did you know that cannabis has two types of leaves? Let’s find out.
The Two Types of Marijuana Leaves
Many cannabis growers ask about how many leaves are there in the cannabis plants. There is no exact number of leaves the marijuana plant can have, however, depending on the type of your cannabis plant, the leaflets (fingers of the leaves) will always have an odd number usually from 7-9, in some cases, the cannabis leaves can have up to 13 leaflets.
There are two types of cannabis leaves you can find in the cannabis plant. These two types of leaves have unique features that differ from each other.
Cannabis plants only produce one kind of cannabis leaves during the vegetative stages in its growth cycle. The leaves you can see sprouting are the fan leaves. Indica-leaning cultivars produce broad leaflets in their leaves, whereas the fingers of sativa-dominant strains, fingers are much more slender.
Fan Leaves
The fan leaves of the cannabis plants differ from the type of cannabis. The leaflets on the fan leaves of sativa dominant cannabis strains tend to be slender and light green while the leaflets of indica dominant cannabis strains tend to be broader and darker in color.
For cannabis hybrid strains, the feature of its fan leaves usually shows the features of the two blended.
These broad leaves are mainly the ones responsible for collecting sunlight for photosynthesis and became the iconic symbol of marijuana all around the world.
This type of leaves contains low quantities of cannabinoids and is usually trimmed during the cultivation phase.
While the fan leaves are one of the underrated and underused parts of the marijuana plant, fan leaves are resinous and contain flavor-packed phytonutrients that promote health and wellness.
Sugar leaves
These types of leaves are usually found close to your cannabis flowers or “buds”. They grow during the flowering stage of your marijuana plants.
Commonly, your cannabis sugar leaves are hidden, and usually, only their tips are peeking through the dense larger cannabis fan leaves.
During harvest, the buds are manicured, or these sugar leaves are removed to make the flower more attractive to the customers. These can be done whether before or after drying and curing.
The distinct feature of sugar leaves is that white, delightful trichomes usually envelop these leaves. It is coated with powdered white sugar and typically contains higher concentrations of cannabinoids than the fan leaves.
Now, let us learn why yellow cannabis leaves appear and how to fix it.
Why Do Yellow Cannabis Leaves Occur?
Mostly, the reason why yellow cannabis leaves appear is that your plant is stressed. Whether to various rights, yellow leaves are the sign that your cannabis plant is sick and seek immediate treatment. To understand why this is happening, we must determine first what made up the leaves and its connection with the plant’s health.
As you already know, plant cells are made up of chloroplasts, the organelles that made up the plant cells that contain the green pigment called chlorophyll that, in turn, absorb different wavelengths of light. The green pigment is the dominant color. However, other pigments are also involved. The other visible pigments that can be seen are the orange and yellow pigments of carotenoids that are hiding under the green chlorophyll.
The role of the chlorophyll is to absorb sunlight to cook food or create energy for the plant. This process is called photosynthesis. Lack of chlorophyll shows that the plant is sick as ample resources for the plants proliferates chlorophyll.
The green pigment of the leaves will deteriorate if the plant is sick and will show the yellow carotenoids that are hiding below the green pigment. These yellow carotenoids cannot absorb sunlight and will not transform the light into energy for plant consumption. Minor cases will eventually stunt your plant or kill your cannabis plant in significant cases.
The Common Causes and Fixes for Yellow Cannabis Leaves
Poor Watering
Of course, water is essential to your plants. If you think watering your plants is enough, you are wrong there. Inadequate or too much water or water at the wrong time can also become a problem for your marijuana plants and will cause yellow cannabis leaves.
Symptoms
Here are symptoms of poor watering practices that result in yellow cannabis leaves.
- Overwatering – if you look closely, the leaves are somewhat fat and swollen, caused by too much water, and result in yellowing and deficiencies.
- Underwatering – if you observe, the cannabis leaves are thin and “papery”, caused by inadequate watering and leads to yellowing and deficiencies.
- Droopiness – droopiness during the beginning of their light cycle is the result of poor water practices.
Causes
- Too much water while your plant is still young leads to over watering as the roots of these plants are still weak and small, unable to absorb much water.
- Too much or insufficient water at times can cause yellow cannabis leaves and can cause droopiness.
- The weak drainage system in your pots can cause overwatering.
- Big plants, small pots, equal to under-watered.
- Small plants, big pots, equal to over-watered.
Solutions
- Use coco coir or good soil for your starting plants.
- Use the right size of your pot for your plants.
- You are overwatering if the leaves of your cannabis plants start dropping after you water them.
- You are underwatering if the leaves of your marijuana plant perk up after you water.
- Learn to water your cannabis plant at the right time.
PH Issues
Whatever the growing medium you use (soil, coco coir, etc.), yellow cannabis leaves are caused commonly by the pH levels of your growing medium.
As you already know, pH levels indicate the acidity. If your growing medium is too alkaline or too acidic, your cannabis plants cannot absorb nutrients as the cannabis plants can only take nutrients when your growing medium is about 5.8 to 6.8 pH. This pH will eventually lead to yellow cannabis leaves.
Symptoms
- Oddly colored or yellow leaves
- Stripes, spots, or patches
- Edges of the leaves are burnt
- Incorrect pH results in a deficiency
Causes
- Inadequate water and growing medium
- pH levels are not compatible with cannabis plants
- Incorrect pH levels for soil, coco coir, and hydroponics.
Solutions
- Always monitor pH levels of your water and growing medium using pH test kits.
- Learn how to correct pH levels.
Nutrient Deficiencies
If you already checked the two above and still have yellow cannabis leaves. It might be useful to look for other causes, and nutrient deficiencies may cause this. Each nutrient deficient shows unique signs and symptoms, and you can use this as a basis for fixing the yellow leaves of your cannabis.
Nitrogen Deficiency
Symptoms
- Even though the leaves look healthy, the leaves are pale green or lime green all over without spots or stripes.
- Yellow leaves appear around the base of the plant.
- Yellow leaves are quickly comfortable to pull and very soft.
- Causes
- All nitrogen on the soil has been used up.
- Using coco coir and hydroponics without replenishing the nutrient
Solution
- Replenish the nutrient in your growing medium
Magnesium Deficiency
Symptoms
- Yellow color between the veins of the leaves and usually can be found on the leaves on the bottom of the plant
- Causes
- Wrong pH levels often cause magnesium deficiency
Solution
- Check the pH level and adjust the pH level suited for your cannabis plant
- If symptoms persist, use magnesium and calcium nutrient for your plant
Iron Deficiency
Symptoms
- The yellowing of leaves only affects new leaves.
- New leaves appear entirely yellow.
Causes
- Unless using purified water or RO, it is mostly caused by incorrect pH levels.
Solution
- Bring your pH level to the correct range.
- If symptoms persist, use iron, magnesium, and calcium nutrient for your plant.
Last words
There are many common causes of yellow cannabis leaves which can be fixed by you. The yellowing of your cannabis leaves indicates that the plant is sick and this needs to be fixed immediately.
Most cases are just watering practices in which almost anybody or any grower will neglect proper methods at first. You can only learn how to balance pH levels in your medium and just replenish the nutrients that are needed by your plant.