Cannabis schematic • click terms, jump to the diagram, come back any time
When training or troubleshooting, you'll see terms like node, internode, apical meristem, and petiole. These refer to specific parts of the plant — and once you can spot them by sight, everything else clicks into place.
The schematic below is a side-view of a young vegetative cannabis plant at roughly your current stage (Day 30–40, 4–6 nodes). Labels point to the key structures. Bookmark this page and return any time a term confuses you.
Below the diagram is a glossary that goes beyond a name — each entry tells you what the part does, not just what it is. For systemic mechanisms like photosynthesis, transpiration, and how light drives growth, see Plant Physiology.
👉 Tap any label on the diagram to jump to its glossary entry — and tap any glossary card to flash the matching label on the schematic. Everything is cross-linked.
Dashed lines point from labels to the structure. Gold dots = nodes. Tap the image for a full-screen view.
Zoom: Node Close-up
The node is where the magic happens — every training decision (topping, LST, defoliation) is relative to a node. Here's what's actually at each one.
A single node magnified. Topping cuts the stem above a node; LST bends the stem between nodes without breaking the node itself.
Zoom: Fan Leaf Anatomy
A cannabis fan leaf is palmately compound — one petiole, multiple leaflets radiating like fingers on a hand. Count the leaflets to gauge maturity (seedlings start with 1, mature veg plants show 7–9).
Leaflets curl, droop, or yellow before the rest of the plant shows stress — they're your earliest warning system.
Zoom: Bud & Flower Close-up
You won't see these structures until the flower stage (after the 12/12 flip, ~Day 60+). Bookmark this for later — harvest timing depends on reading trichomes and pistils correctly.
Inspect trichomes with a 60× loupe or phone macro clip. Harvest when most are milky with ~10–30% amber — that's peak potency for an even head+body effect.
Key Terms Glossary
Node
The point on the main stem where leaves and/or branches emerge. Count nodes bottom-up. You currently have 4–6 nodes per plant.
Function: growth junction. Vascular bundles (food + water highways) cross here, which is also why nodes have hormonal "memory" — topping the apex tells nodes below to fire their axillary buds.
Internode
The bare stem between two nodes. Short internodes = bushy compact plant. Long internodes often mean the plant is reaching for more light.
Function: the structural spacer + plumbing. Internode length is your live readout for light intensity (long = stretching, short = saturated) and for stage (stretches violently in the first 2 weeks of flower).
Apical meristem
The growing tip at the top of the main stem. In flower this becomes the main cola. Topping = cutting this off to force two new tops.
Function: hormone factory. Produces auxin that flows downward and suppresses side branches (apical dominance). Cut it off and the suppressed buds wake up — that's why topping works.
Cola
A cluster of flower buds. The "top cola" is the biggest one at the apex. Training goals are usually stated in colas (e.g., "8 colas before flip").
Function: the harvestable structure. SCROG/LST trades one giant cola for many medium ones because total bud mass scales with light-exposed surface, not stem height.
Fan leaf
The big classic 7- or 9-finger serrated leaf. These are the plant's solar panels — keep them healthy, only remove selectively.
Function: photosynthesis (light + CO₂ → sugars) and transpiration (pulls water up from roots via stomata on the underside). Removing healthy fan leaves cuts both sugar production AND the water pump that drives nutrient uptake.
Sugar leaf
Smaller leaves growing directly from buds during flower. Often trichome-covered (hence "sugar"). Trimmed at harvest.
Function: a final layer of photosynthesis right next to the developing flower. Trimmers remove them at harvest because their trichomes are lower quality and they harsh up smoke.
Petiole
The thin stalk attaching a leaf to the stem. You cut here when removing a fan leaf cleanly.
Function: two-way pipe. Xylem (inside) carries water + minerals up to the leaf; phloem (outer ring) carries sugars made by the leaf back down to roots and buds.
Axillary bud
The new growth point at each node, tucked where the petiole meets the stem. After topping, these become the new main colas.
Function: dormant growth reserve. Held inactive by auxin from the apex. Wakes up when the apex is cut, damaged, or far enough away — the mechanism behind topping, FIM, and supercropping.
Cotyledons
The two round "baby leaves" present at seedling emergence. They yellow and drop naturally — this is normal, not a deficiency.
Function: the seed's built-in food reserve and first solar panels. Once true leaves take over photosynthesis, the plant disassembles cotyledons for nitrogen — that's the yellowing you see.
Main stem
The central trunk. In LST you bend this horizontally. In topping you cut the top of it off.
Function: structural backbone + main vascular trunk. Strengthens in response to wind/wobble (silica + slight stress thicken it). A weak floppy stem is usually too little airflow, not genetics.
Pistil
The white/orange hairs on flowers. They start white and turn amber as the plant ripens — one of the harvest timing cues.
Function: evolved to catch pollen from male plants. With no males in your tent it'll never get the job done — which is exactly what makes the calyx swell with resin instead of seeds (sinsemilla).
Trichome
Microscopic resin glands on buds and sugar leaves. Inspect with a 60x loupe: clear → milky → amber tells you when to harvest.
Function: chemical defense (deters insects + UV). Inside the gland head: THC, CBD, and terpenes. Heat, light, and rough handling degrade them — this is why dry/cure technique matters so much.
Leaflet
Each individual "finger" of a compound fan leaf. Seedlings start with 1 leaflet; mature plants show 7 or 9 per leaf.
Midrib
The central vein running the length of each leaflet. Smaller lateral veins branch off it, feeding the tissue.
Serration
The saw-tooth edge of each leaflet. Classic cannabis shape. Not functional for you — just a visual ID cue.
Stipule
Tiny leaf-like structures at the base of a node where petioles attach. In flower, stipules are where pre-flowers appear (your first sex indicator).
Calyx
The teardrop-shaped structures that make up a bud. Densely coated in trichomes. Technically false fruits — botanists call them bracts.
Stigma
The sticky tip of each pistil (the white hair). Designed to catch pollen. Transitions white → orange → red as ripening progresses.
Phyllotaxy
Leaf arrangement on the stem. Cannabis starts opposite (pairs) and shifts to alternate (staggered) around node 6–7 at sexual maturity.
Pre-flower
Tiny structures appearing at nodes ~3–6 weeks into veg that reveal sex before true flowering. Pistil = female, pollen sac = male (remove immediately).
Growth Zones
Canopy
The uppermost leaves catching direct light. Training is all about keeping the canopy flat and even so every bud site gets equal light.
Understory
Everything below the canopy. In flower, low popcorn buds here often get stripped ("lollipopping") so the plant puts energy into the top colas.
Root zone
Everything below the soil surface. Wick-fed pots keep this evenly moist passively. Healthy roots = healthy everything above.
Function: water + dissolved-nutrient intake (driven by transpiration, not pumping); structural anchor; hormone factory (cytokinins flow up). Root rot in a wet res → whole plant droops — this is why Hydroguard and oxygen matter.