No part of any plant is as widely-recognized as the serrated green fingers of the cannabis leaf, (for us, anyway) but these leaves are far more than just a cultural meme. They play a critical role in the health and wellbeing of the plant. And, while less potent than the sticky flower, the leaves can still be put to good use – you should never just put them in the garbage! Leaves are great for green teas, smoothies and raw cannabis juice. You can use them for topical creams and balms and the sugar leaves are great for cannabis butter and hash. Adding them to your compost is more beneficial than tossing them away – they will decompose and feed future generations of plants. But what purpose do they serve while the plant is still alive? What are they made of? What is their job? How can you make the most of cannabis leaves both on and off the plant?
What do cannabis leaves do?
A cannabis plant wastes no time unfurling its first set of leaves. As soon as the taproot has anchored the stem, the little plant shoots up and spreads tiny green wings. Clearly, these leaves are vital, but what exactly do they do?
- Photosynthesis. The food factory of the plant is found in the leaves. Carbon dioxide and water are turned into vital carbohydrates, using light from the sun or lamp. Without the waste product, oxygen, you wouldn’t be alive to read this article – plants do far more than get us high!
- Food Storage. Apart from food production, the leaves also serve as food and water storage.
- Transpiration. As with humans, plants sweat to cool down. The process begins with the absorption of moisture through the roots. The water is used in photosynthesis and any excess is released as vapor from the underside of the leaves, cooling the plant.
- Florigen production and translocation. The flowering hormone, Florigen, is produced in the leaves when light drops to 12 hours or less. It’s then transported to various parts of the plant.
What are cannabis leaves made of?
Cannabis leaves are made up of different parts, each with a particular purpose and use.
- Beam. The upper side of the leaf that acts as a solar panel. Usually colored bright green.
- Envelope. Found on the underside of the leaves, this is where most stomata are located. Like the beam, it’s also light green in color.
- Petiole. The appendix of the leaf that connects it to the stem.
- Stipule. Located at the base of petiole, it’s a leaf appendix that sprouts around the knot.
- Leaflet. Also called nerve, foliole or pinna, it’s the separate part of each leaf blade. A cannabis leaf has several of these.
- Vascular System. The network of veins that transports nutrients from outside and within the leaf.
What is the general structure of a cannabis leaf?
Unlike most of other plants of the Cannabaceae family, cannabis leaves are decussate-opposite, emerging in pairs on both sides of the stem (during veg). As the plant approaches flowering, it switches to a more common, alternate-leaved pattern.
Interestingly, some studies show that early-planted hemp, when flowering under lower light conditions, displays new alternate leaf outgrowths when exposed to more hours of light. The number of leaflets eventually increases as new growths continue. While the genetic process responsible for such untypical behavior is not yet understood, it’s believed that it may lead to better vegetative development.
What are the leaf differences among subspecies of cannabis?
The three cannabis strains, Sativa, Indica, and Ruderalis, express some striking differences. From chemical composition to structure to height, each one is different in its own, special way. Even their leaves are distinguishable, with Sativa blades being the most serrated and pointy.
|Number of Fingers||Up to 13||7 to 9||5 to 13|
|Length and Breadth||Long and Slender||Wide and Fan-like||Equal or Narrower than Indica|
|Color||Dark Green to Dark Lime Green||Deep Love Green||Light Green|
Note: Due to the widespread hybridization of cannabis varieties, a Sativa-heavy crossbreed may display Indica physical attributes and vice versa. Landraces are far easier to segregate than hybrids.
Do cannabis leaves ever show mutations?
Malformed cannabis leaves are not uncommon. They are often products of the genetic irregularities prevalent in some hybrids. They’re rarely a sign of ill health. In some cases, deformities have been purposely bred into cannabis strains in order to mask their true identity. Don’t forget, most of the world lags behind the US when it comes to cannabis prohibition!
- Ducksfoot “webbed” cannabis. This mutation produces webbed, duckfoot-like leaves unlike typical cannabis blades. It has been deliberately bred into new varieties such as Frisian Duck. The landrace Hawaiian Duckfoot also displays this quirky shape.
- Australian Bastard Cannabis. Bindi Buds or Cannabis Australis (not a real botanical name) was first discovered in the Australian countryside not far from Sydney, sometime around the 70s or 80s. It was introduced to the world during the 90s and renamed as Australian Bastard Cannabis (ABC). This plant is so unlike regular weed that it fools botanists and breeders in equal measure. Its shiny, smooth and non-serrated leaves are no more than 5cm in length and grow in a flowery formation. It’s not commercially available as the leaf attribute is highly recessive and, therefore, hard to pass on.
- Variegation and Albinism. These anomalies are caused by the inability to control chlorophyll production, resulting in pigmented and non-pigmented sections on the leaves. Although visually appealing, this mutation affects the rate of photosynthesis, which can negatively impact health, quality and yield. Full albinos never survive to full maturity.
- Whorled Phyllotaxy. Making a cannabis plant extra bushy, a whorled arrangement sees the growth of three or more leaves from a single node (instead of the usual two). Plants with this abnormality also develop an additional branch at every internode. Although the mutation can increase yields, it cannot be replicated or passed on.
- Leaf Buds. Typically, flowers appear at the nodes where petioles spring up. With this aberration, though, the bud sprout at the base of the leaves, which is why it’s often referred to as the piggyback mutation.
Alternative uses for cannabis leaves
As we touched on earlier, instead of disregarding or discarding your cannabis leaves, they can be put to good use.
Using cannabis leaves to determine plant health
The eyes are the window to the soul. You could say the same about cannabis leaves! The condition of the leaves can reflect a plant’s overall health, offering observable clues to potential issues. Here are the most common leaf abnormalities and what they indicate:
|Leaf Condition/Symptoms||Nutrient Problem||Environment||Feeding||Body Problem|
|Black or Gray Patches||Phosphorus Deficiency||Pests (Fungus Gnats) or Viruses|
|Dark or Purple Leaves||Copper, Boron, or Phosphorus Deficiency or Nitrogen Toxicity||Pests, Viruses, Mold, or Wind Burn|
|Mottling or Mosaic Pattern||Manganese, Phosphorus, Calcium, Zinc, or Magnesium Deficiency||Pests (Spider, Broad, Russet Mites), Viruses, Bud Rot, Mold, or Wind Burn|
|White Powder Patches||White Powdery Mildew|
|Red or Pink Color||Copper, Sulfur, or Phosphorus Deficiency, or Root Problems|
|Yellowing Old Leaves||Copper, Potassium, Manganese, Phosphorus, Nitrogen, Sulfur, Magnesium, or Molybdenum Deficiency, or Nitrogen Toxicity||Pests (Spider Mites) or Viruses||Under-watering||Root Problems|
|Yellowing New Leaves||Copper, Potassium, Manganese, Phosphorus, Zinc, Iron, Sulfur, Magnesium, or Molybdenum Deficiency||Pests (Spider, Broad or Russet Mites, Fungus Gnats), Viruses, Wind Burn, Bud Rot, or Mold||Under-watering||Root Problems|
|Brown or Dark Spots||Manganese, Boron, Phosphorus, Calcium, Magnesium, Molybdenum,||Pest (Spider, Broad, or Russet Mites, Fungus Gnats) pH Fluctuations, Light Burn, or Wind Burn||Under-watering||Root Problems|
|Brown or Burnt Edges||Copper, Potassium, Boron, Magnesium, Phosphorus Deficiency, Nutrient Burn, Nitrogen Toxicity||Pests (Fungus Gnats, Broad or Russet Mites), Heat Stress, Light or Wind Burn, Bud Rot, or Mold||Under-watering or Over-watering||Root Problems|
|Pale Leaves||Copper, Potassium, Manganese, Boron, Phosphorus, Nitrogen, Sulfur, Iron, Magnesium, or Molybdenum Deficiency||Pests (Fungus Gnats, Spider Mites), White Powdery Mildew, Light Burn, Bud Rot, or Mold||Under-watering||Root Problems|
|Veins Stay Green||Copper, Potassium, Manganese, Iron, or Magnesium Deficiency, Nutrient Burn, or Nitrogen Toxicity||Pests, Viruses, Light Burn, or pH Fluctuations||Root Problems|
|Yellowing Between Veins||Copper, Potassium, Manganese, Nitrogen, Zinc, Sulfur, Iron, or Magnesium Deficiency, Nitrogen Toxicity||Pests (Fungus Gnats), Viruses, or Light Burn||Root Problems|
|Leaves Curling Under||Copper, Phosphorus, Zinc, or Magnesium Deficiency, Nutrient Burn, or Nitrogen Toxicity||Pests (Fungus Gnats, Broad or Russet Mites), Light or Wind Burn||Under-watering or Over-watering||Root Problems|
|Leaves Curling Upwards||Magnesium Deficiency, Nutrient Burn, or Nitrogen Toxicity||Pests (Broad or Russet Mites), Light or Wind Burn, or Heat Stress||Under-watering||Root Problems|
|Old Leaves Dropping Off||Phosphorus, Nitrogen, or Magnesium Deficiency||Pests (Broad or Russet Mites)||Under-watering||Root Problems|
A daily dose of low-strength cannabis
Not everyone can afford to get high every day, but this shouldn’t mean we have to stop benefitting from cannabis. By using the leaves, rather than the potent buds, growers can enjoy the health-giving properties of marijuana seven days a week, with or without the (very subtle) buzz.
Cannabis leaves possess nutrients such as calcium, fiber, iron, phosphorus and potassium. They are also home to also (smaller amounts of) beneficial cannabinoids and terpenes.
Beneficial chemicals found in cannabis leaves
- THCA. This compound has anti-inflammatory and neuroprotective properties. It can stimulate appetite and reduce nausea. Turns into THC after decarboxylation.
- CBDA. Boasts anti-depressant properties, can reduce seizures and nausea, and can potentially inhibit cancer cell growth. It becomes CBD when decarboxylated.
- Pinene. Rich in anti-inflammatory and anti-cancer properties, acts as a natural bronchodilator and expectorant.
- Mycerene. A known anti-inflammatory and antibiotic agent.
- Limonene. Contains anti-inflammatory and anti-cancer properties. Can promote weight loss.
- Has anti-aging and anti-inflammatory properties
- Possible anti-cancer compound
- Prevents iron deficiency and anemia
How to eat cannabis leaves
Fresh cannabis blades can be used to enhance a variety of dishes:
- Use frosty trim or sugar leaves to make hash or other concentrates
- Cook or bake edibles with fan leaves
- Brew a cannabis leaf tea
- Make a smoothie or bhang
- Mince and add as herb topping to dishes like soups, oven-baked meals, steak, etc.
Spread Or Smear
Just like buds, cannabis leaves can also be turned into creams and topicals. The fresh blades can be ground into paste or heated with oils for a variety of localized issues.
- Some types of dermatitis and psoriasis
- Lip blisters
- Superficial wounds or cuts
- Acne and pimples
- Localized pain
Cannabis leaves: not so useless, after all!
They may not offer the amazing high and powerful medicinal properties of the flower, but cannabis leaves are far from useless. They are absolutely essential to the plant’s growth, acting as solar collector, storage facility, thermal regulator and hormone producer. They contain numerous beneficial compounds and, at the very least, they make good, fast-decaying compost! The range of teas, topicals and treatments you can make from leaves is vast, with psychoactive effects that are subtle, if felt at all.
The best growers make use of each part of their plants, so next time you pick up your trimmings, perhaps you should pause for a second to consider their true potential… Cup of tea, anyone?