How to read a Certificate of Analysis (COA), section by section.
If you've ever opened a lab report and immediately closed it, this is for you. We'll walk through every panel — cannabinoids, terpenes, pesticides, heavy metals, microbials — and explain what each number actually tells you about the flower in your jar.
What a COA actually is
A Certificate of Analysis is the document an independent lab issues after testing a specific batch of cannabis. It's not a marketing brochure. It's a chain-of-custody-tracked report that says: "On this date, we received this sample from this producer, ran these tests using these methods, and these are the results."
The good ones are issued by ISO/IEC 17025 accredited labs — that's the international standard for testing competence. If a COA doesn't show an ISO 17025 accreditation number on the header, treat it skeptically.
Section 1 — Header and chain of custody
The first thing on every COA: the lab's name, accreditation number, and the sample's chain of custody. You should see a unique batch or sample ID (matching the jar), the date the sample was received, the date testing was completed, the producer's name and license number, and the matrix tested (e.g., "dried inflorescence"). If any of those are missing, the report has integrity problems before you even get to the data.
Section 2 — Cannabinoid panel
This is what most people look at first. You'll see a table of every measurable cannabinoid: THCa, Δ9-THC, CBDa, CBD, CBG, CBN, and friends. Each row will show % by weight, mg/g (1% = 10 mg/g), and the LOQ (Limit of Quantification — the smallest amount the lab can reliably measure).
For hemp-derived THCa flower, you're looking at two key numbers. First, Δ9-THC must be below 0.3% — that's the federal Farm Bill threshold. If it's above, the flower is not legally hemp. Second, THCa is the headline potency — when you light it, THCa converts to Δ9-THC, so a 27% THCa flower behaves like a 27%-ish THC flower.
You'll often see "Total THC" calculated as Δ9-THC + (THCa × 0.877). The 0.877 accounts for the molecular weight lost during decarboxylation. It's a useful reference number but not a regulatory one.
Section 3 — Terpene profile
Terpenes are the aromatic compounds that give each cultivar its smell and (likely) shape its effects. A good terpene panel reports the top 20-40 by % weight. Limonene reads citrus and uplifting; myrcene is earthy and sedating; caryophyllene is peppery; terpinolene is fresh and cerebral.
Total terpene content (the sum of all detected terpenes) is a decent quality indicator. Anything above 2% on dried flower is solid; above 3% is exceptional.
Section 4 — Pesticide panel
This is where it gets serious. The lab tests for 60-70 specific pesticides at parts-per-billion sensitivity. You want to see "ND" or "<LOQ" on every line (meaning non-detect, below the lab's lowest reliable measurement) and "PASS" in the summary column. "ND" does NOT mean "we didn't test for it." It means the lab tested specifically for that compound and found none above its detection threshold.
Section 5 — Heavy metals, microbials, mycotoxins
Cannabis is a notorious bioaccumulator — it pulls heavy metals out of the soil. The standard panel tests Arsenic, Cadmium, Lead, and Mercury. Microbials cover E. coli, Salmonella, and Aspergillus species. Mycotoxins (aflatoxin, ochratoxin) catch what some molds leave behind even after the mold itself dies. Across all of them, you want "PASS" or "ND".
Red flags to watch for
Test date older than 12 months — terpenes degrade, the report no longer represents the product
"Sample collected by producer" — chain of custody compromised; lab should collect or witness collection
No accreditation number — could be a non-accredited lab
Pesticide panel with only 5-10 analytes — should be 60+ for a thorough screen
Δ9-THC at 0.29% — suspicious; suggests the producer is selling at the absolute legal ceiling
Bringing it back to the jar
Every LeafTek jar has a batch ID printed on the label (format LT-YYYY-MM-strain-N). Search that ID on our lab results archive or scan the QR code on the jar. The COA you'll get is the actual document the lab issued — not a marketing summary, not a re-typed version.
The indica/sativa split that every dispensary uses to organize a menu is closer to marketing folklore than to plant science. Here's what it actually maps to, why it falls apart the moment you look at chemistry, and what to use instead.
Where the indica/sativa labels come from
Botanically, Cannabis sativa and Cannabis indica were named based on plant morphology — leaf shape, height, branching, internodal spacing — observed in the 18th and 19th centuries. Those visual differences are real, but after 50+ years of cross-breeding they say almost nothing about how a given jar of flower will affect you.
What people mean when they say "indica" or "sativa"
The shorthand most consumers and budtenders use is functional, not botanical. "Indica" is a stand-in for "calming, body-heavy, evening." "Sativa" is "energizing, head-forward, daytime." The problem: the same plant can be morphologically indica and chemically energizing, or vice versa. Lineage and chemovar matter more than the indica/sativa label on the menu.
What to look at instead
Three things tell you far more than the indica/sativa label:
Dominant terpene. Myrcene-dominant flower tends to feel sedating. Limonene-dominant feels uplifted. Terpinolene-dominant skews cerebral and clean. Caryophyllene-dominant lands in the middle, with a calming body note.
Total terpene content. 2%+ is good, 3%+ is exceptional. Low terps = bland flower regardless of label.
Cannabinoid ratio. A flower with CBG or CBD alongside the THCa often feels less heady than pure-THCa flower at the same potency.
How we organize our own catalog
We still use the indica/sativa/hybrid label because customers find it easier to scan. But every product page lists the dominant terpene, total cannabinoids, and an "effect" tag (Social, Creative, Calm, Focused, Sleepy) derived from internal tasting notes. If you've ever felt let down by a "sativa" that didn't feel energizing, the effect tag is the more reliable signal.
Properly stored, premium flower holds its terpene profile for months. Poorly stored, it loses the volatile notes (the ones that smell like fruit and pine) within weeks. Here are the four enemies and what to do about each.
Enemy 1 — Humidity
Target range: 58-62% RH. Below 55% and the flower gets brittle, harsh, and crackly. Above 65% and you risk mold (especially on dense indoor flower). Boveda or Integra Boost 2-way humidity packs (62% rating) inside an airtight jar will hold the range for months without intervention.
Enemy 2 — Light
UV breaks down both cannabinoids and terpenes. Clear glass jars on a sunny shelf are the fastest way to dull a beautiful jar of flower. Opaque containers, or clear jars stored in a dark cabinet, solve it.
Enemy 3 — Heat
Volatile terpenes evaporate faster at room temperature than at cellar temperature. Below 70°F is fine; below 60°F is better. Avoid the freezer — repeated freezing/thawing causes the brittle trichomes to snap off the buds.
Enemy 4 — Oxygen
Oxygen oxidizes THCa to CBN over time, which trades headiness for sleepiness (and dampens the overall character). An airtight seal beats a screw-top mason jar; vacuum-sealed mylar beats both. That's why we vacuum-seal every jar within 48 hours of purchase — by the time it gets to you, oxidation hasn't started.
The 6-month rule of thumb
Properly stored — airtight, dark, room temperature, humidity-controlled — premium flower holds 90%+ of its terpene profile at six months. Past that, terpenes degrade noticeably even with perfect storage. After a year, you've still got flower but not the flower you bought.
State-by-state THCa legality, current as of Q2 2026.
Hemp law has changed more in the last 18 months than in the previous five years. This is a clean reference for the 27 states we don't ship to and the 23 + DC we do, with citations to the underlying statutes.
The federal floor
The 2018 Farm Bill defines hemp as cannabis with less than 0.3% Δ9-THC by dry weight. Hemp-derived products (including high-THCa flower) are federally legal under that definition. Section 781 of the FY2026 Continuing Appropriations Act is scheduled to redefine that floor effective 2026-11-12 — we'll be republishing this guide before then.
States moving to "total THC" calculations
Several states have responded by applying a "total THC" standard: Δ9-THC + 0.877 × THCa ≤ 0.3%. Under that math, almost no commercially viable THCa flower is lawful. Georgia (SB 494), Mississippi (HB 1676), North Dakota, South Dakota, and Virginia (SB 903) all fall in this group.
States routing through licensed cannabis channels
Other states haven't tightened the chemistry — they've channeled intoxicating hemp through the existing cannabis dispensary licensing system. California (AB 8), Colorado (SB 23-271), Connecticut (PA 24-76), Maryland (Cannabis Reform Act), and Nevada all sit here. The product is legal to consume, just not legal to ship in from out of state.
Outright bans on smokable hemp
A smaller group has banned smokable hemp entirely: Alabama (HB 445), Arkansas (Act 629), Iowa (HF 2605), Kentucky (302 KAR 50:070), Louisiana (Act 752), Utah, Washington (SB 5367), and Wyoming (HB 198).
Where we still ship
The 23 states + DC we currently ship to are: AZ, DE, FL, IL, IN, KS, MA, ME, MI, MO, MT, NC, NE, NH, NM, OH, OK, PA, SC, TX, VT, WI, WV, and Washington DC. The live list is at our shipping API docs.
Cannabis produces 150+ different terpenes, but four of them dominate most premium flower. Recognize these and you can predict roughly how a strain will feel before you ever light it.
Limonene
Smells like citrus peel. Common in Jungle Juice, Lemon Sequoia, Amber Tangerine. Tends to read uplifted, social, daytime. Limonene degrades quickly in light and heat — citrus-forward flower especially benefits from cold, dark, airtight storage.
Myrcene
Earthy, herbal, slightly fruity. Common in Purple Burner, Midnight Pacific. Tends toward calm, body-heavy, sedating. Myrcene is also abundant in mangos and hops — the "mango trick" of eating fresh mango before consuming has some merit because of this overlap.
Caryophyllene
Peppery, clove-like, slightly spicy. Common in Gelato Bar, Cherry Vermouth. Notable as the only terpene that also binds to CB2 receptors, which is why caryophyllene-rich flower can feel relaxing without feeling heavy.
Terpinolene
Fresh, herbaceous, with notes of pine and apple. Velvet Static and (in smaller amounts) Lemon Sequoia carry it. Tends to read cerebral, creative, clean. People often describe terpinolene-dominant flower as "feeling like nothing" until they're 20 minutes into it.
How to use this when shopping
Pick the effect you want, then pick the terpene that maps to it. "Daytime social" → limonene. "Wind down" → myrcene. "Relaxed but functional" → caryophyllene. "Creative work session" → terpinolene. Then look at the COA to confirm meaningful concentration (above 0.5% is meaningful; above 1% is strong).