CLN · LAB SCIENCEFrom Trichome to THC%1 / 7
MICROSCOPE — 400×
100 µm
THCa — in resin
THC — after heat
Resin head (stores THCa) Secretory disc Stalk THCa molecules
Trichome cluster sugar leaf surface THCa inside each head Leaf vascular tissue (low THC)
Sugar leaf (some THC) Calyx & bract highest trichome density Trichomes coating surface Pistils — 0% THC
Top Cola Highest THC Fan leaf Few trichomes Side bud Medium THC Main stem — very low THC HIGH LOW THC
Roots — 0% THC Top cola: ~20–30% THC Side buds: ~15–22% Fan leaves: ~1–5% Stem: ~0.1–1%
Lab sample: ALL plant parts mixed together Trichomes knocked loose Ground mix = bud + leaves + crystals → This mixed material is the test sample
1 GRAM = 1000 mg plant water THCa Component % mg Plant fiber ~58% ~580 Moisture ~15% ~150 THCa ~17% ~170 CBD/CBG ~3% ~30 Terpenes ~4% ~40 Waxes ~3% ~30 Total 100% 1000 20% label on package = 170mg THCa + 5mg THC × 0.877 (decarb conversion) ~175mg active THC 825mg is everything else 20% = 175mg per gram after heat HPLC CHROMATOGRAM Peaks = cannabinoids detected in solution HIGH LOW THCa 17.2% CBD 1.2% THC 0.8% CBG 0.4% Retention time → Total THC = (17.2 × 0.877) + 0.8 = 15.9% → labeled ~20%
Scale: 400× microscope

The trichome

A single capitate-stalked trichome head is the entire THC factory. Secretory cells inside the bulbous head synthesize THCa — the raw, non-psychoactive form — and store it in a resin cavity.

This microscopic globe, invisible to the naked eye, is where 100% of the psychoactive potential in cannabis originates.

Head: 50–100 micrometers wideTHCa stored inside: very high concentrationNot yet psychoactive — needs heat
Scale: ~1mm surface view

Sugar leaf cluster

Zoom out and you see trichomes packed densely across a sugar leaf — the small leaves that grow directly from the bud. Each glowing head is storing THCa in its resin cavity.

The green leaf tissue underneath has almost no THC. All value is sitting in the heads above the surface.

~10,000–30,000 trichomes per cm²Sugar leaf THC: ~5–10% (lower than bud)Leaf blade: ~0.1–1% THC
Scale: ~1–3 cm bud

The flower

The calyx and bracts of the flower have the highest trichome density on the plant. The bud is essentially a compression of thousands of trichome-coated surfaces.

The orange pistils (hairs) you see contain zero THC — they're reproductive organs for catching pollen.

Calyxes: highest THC density on plantPistils: 0% THCTypical flower: 15–30% total THC
Scale: ~10–30 cm branch

Branch: buds, leaves, stem

A branch carries the full mix — top cola, side buds, fan leaves, and the woody stem. THC concentration drops sharply the further you move from the flower.

This matters because lab samples may include bits of stem and leaf that dilute the final number.

Top cola: ~20–30% THCFan leaves: ~1–5% THCMain stem: ~0.1–1% THC
Scale: full plant, ~1–3 meters

The whole plant

From roots to cola tip, THC tracks exactly where trichomes live. Roots have zero. Stems have trace. Fan leaves are low. Flower calyxes are the highest point on the whole plant.

The lab doesn't test the whole plant — it tests a small sample drawn from harvested, trimmed flower.

Roots: 0% THCStem: ~0.1% THCTop cola: highest on plant
Lab prep: grinding

The grinder — homogenizing

Before any measurement, the lab grinds the sample into uniform powder. Grinding knocks trichome heads off the plant material and blends everything together.

The resulting mix — bud fragments, sugar leaf bits, trichome crystals — is what goes into the solvent and then the HPLC machine. The % reflects this blended reality.

Sample size: typically 0.5–2 gramsHomogenized = averaged across all partsPlant matter ≠ trichome resin
The result: what 20% really means

The number on the label

The HPLC machine reports how many milligrams of THCa it detected per gram of sample. Divide by 1,000 and you get the percentage. Apply the decarb factor (×0.877) and you get active THC.

"20% THC" means roughly 175mg of that gram will become active Δ9-THC when you apply heat. The other 825mg is plant matter, water, waxes, terpenes, and minor cannabinoids.

20% = ~175mg active THC per gram825mg of that gram = everything elseTHC% = mg of THC ÷ 1000mg × 100