Weed leaves are key components of the cannabis plant’s life support system. The green pigment chlorophyll allows leaves to act as solar panels for marijuana. Leaves are essential to photosynthesis. Moreover, the underside of leaves are covered in tiny stomata. These microscopic holes open and close like a door. Carbon dioxide goes in, oxygen and water goes out. Furthermore, leaves can also absorb nutrients to feed the cannabis plant, this is known as foliar feeding.

Leaves Covered In Tiny Stomata


Three kinds of cannabis species are generally agreed upon. Although all three are often lumped together under the official classification of Cannabis sativa L., for practical purposes, it helps to make distinctions between sativa, indica, and ruderalis. That being said, most cannabis you encounter these days is a hybrid. Thus, what you will typically see in the grow-op are weed leaves that express a blend of genetic traits.

Sativa Cannabis LeafSATIVA

Sativa leaves are long and slender-fingered. Some can develop as many as 13 fingers. Usually, sativa plants will have a lighter, lime green shade. It is believed that the reduced chlorophyll is partly responsible for the longer flowering period of sativa strains.

Indica Cannabis LeafINDICA

Indica leaves are short and wide, typically with 7-9 fat fingers. The heaviest indicas of Afghan origin can have oversized, extra-wide fan leaves. Indica leaves are a darker, deeper shade of green. The higher chlorophyll content is believed to accelerate the bloom cycle of indica varieties.

Ruderalis Cannabis LeafRUDERALIS

Ruderalis leaves are quite thin and only develop 3-5 slender fingers. Most growers describe them as comparable with the leaves of young sativa plants. Think of them as miniature sativa leaves with fewer fingers. These leaves are special as they have evolved to give autoflowering cannabis the ability to flower independent of the hours of light it receives.


Cannabis can display leaf mutations. Some of these mutations are initiated by breeders to better camouflage the plant and make it less identifiable as marijuana. Other times, mutations are a minor defect inherent to some strains. Apart from the common, gnarly-looking sets of leaves that appear on young plants, widespread leaf mutations with even numbers of fingers and ugly deformities are very rare. Excessive mutations are indicative of bunk genetics and poor breeding practices.


You don’t need to be a shaman or a tree-hugger to communicate with your cannabis plants. You just need to be informed. The leaves on your cannabis plants can send you an SOS, but you must have the knowledge to decode it and take appropriate measures to fix the problem.

Indica and Sativa Cannabis Leaves


An eyeball inspection might be insufficient to accurately diagnose a possible pest infestation. Discolouration of leaves is not enough evidence to jump to conclusions. However, a thorough eyeball inspection will reveal some pests’ presence. Leaf miners will leave telltale tunnels as they eat their way through leaves. If you see white veins running through leaves, it’s time to get some neem oil.

A visual inspection using a pocket microscope will reveal the presence of other microbial nasties. Be on the lookout for eggs, larvae, fungal spores, and mould. Leaf septoria is caused by the fungus Septoria lycopersici. This particular invader is often misdiagnosed as one of many possible nutrient deficiencies. Yellow spots suddenly presenting on leaves early in flowering, followed by a rapid yellowing and browning of foliage can destroy the whole crop rapidly. There is no time to waste with misdiagnosis.


Yellow leaves are a warning sign and a cry for help from the cannabis plant. Unfortunately, many nutrient deficiencies, over-fertilisation, and heat stress can cause leaves to yellow and wither. It’s so important to closely monitor your cannabis crop, be it indoors or outdoors. If you have been paying attention, you can take corrective action with more confidence diagnosing.

Fluctuations in pH are responsible for the majority of yellow leaves. When the water pH is outside of the optimal ranges for your growing medium, the roots cannot access all the nutrients they need. Nutrient lockout is perhaps the most common cause of yellow leaves in cannabis plants.


Fan leaves have very low cannabinoid content and are best added to the compost heap for next season’s super soil mix. Sugar leaves, or the resinous trim leaf that a grower accumulates during the harvest process, is excellent raw material for homemade cannabis concentrates.

Dry those frosty trim leaves in a brown paper bag like you would popcorn buds. After a couple of weeks, put them in a Pyrex lunchbox and store them in the freezer until you decide on what kind of extract you want to make. Shakers can be filled with sugar leaves to extract pollen. You can also use isolator bags to make bubble hash; the choice is yours. With a little stoner ingenuity, leaf trim can be easily converted into top-shelf hash.

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