A cultivation certificate is not a farming prize — it is a promise that every action taken on the crop was written down before it happened and can be shown to a stranger years later.
1. What This Standard Is and Where It Comes From
Good Agricultural and Collection Practice, shortened to GACP, is a quality assurance framework for plants that will become pharmaceutical starting material. It asks whether material leaving your gate has known identity, origin and contamination status, and whether you can prove it. Its anchor text is the European Medicines Agency’s Committee on Herbal Medicinal Products guideline, EMEA/HMPC/246816/2005 Rev. 1, adopted 12 January 2006 and revised for consultation on 20 March 2024, which requires that “batches of herbal substances should be unambiguously and unmistakeably traceable to their sources.”
2. Where Cultivation Practice Ends and Manufacturing Practice Begins
The cultivation standard governs the living and freshly harvested plant, from seed through irrigation, plant protection, harvest and drying to packed storage. Manufacturing practice takes over once the material becomes a medicine — in Europe, EudraLex Volume 4, whose Part I covers the pharmaceutical quality system, personnel, documentation, production, quality control and self inspection, with Annex 7 on herbal medicinal products and Annex 16 on batch certification by a Qualified Person. The split most projects apply — cultivation and primary drying under the agricultural standard, extraction under the manufacturing standard — is general industry practice; the Annex 7 boundary table could not be retrieved here, so no clause-level split is claimed.
| Aspect | Cultivation and collection standard | Manufacturing standard |
|---|---|---|
| Governs | Crop, harvest, drying, packing, storage | Manufacture of the medicine |
| Anchor | Guideline EMEA/HMPC/246816/2005 Rev. 1 | EudraLex Volume 4 and annexes |
| Core unit | Batch traceable to its source | Manufactured batch, certified |
| Release | Buyer accepts against specification | Batch certification, Annex 16 |
3. The Documentation Core
An Undocumented Action Did Not Happen
The guideline requires documentation of “all processes and procedures that may impact the quality of the product,” and manufacturing practice adds that records must show “all the steps required by the defined procedures and instructions were in fact taken.” An auditor arriving a year later cannot smell your drying room: a gap in a log means control was absent and that material is unproven.
Traceability From Mother Plant to Finished Lot
A mother plant carries a unique code, cuttings inherit a propagation batch number, and at harvest the block becomes a dated lot, each later step recording input, output and yield. The test is bidirectional: from a finished lot you must reach the mother plant and every spray, and from a spray record every lot that could carry residue. Thailand’s 2025 framework demands seed-to-sale records covering seed provenance, fertiliser logs, pest-management reports, harvest dates and quality-control tests.
| Record type | What it must show | Common failure |
|---|---|---|
| Procedures | Approved, versioned, dated | Two versions in circulation |
| Training | Who, on what version, by whom, when | Real but undocumented |
| Seed and propagation | Identity, provenance, mother plant lineage | Genetics of unclear origin |
| Irrigation and fertiliser | Source, product, rate, date, test results | Rates from memory |
| Plant protection | Product, rate, date, interval to harvest | Missing interval to harvest |
| Environmental monitoring | Temperature, humidity, daily indoor parameters | Data never reviewed |
| Harvest and drying | Lot, dates, weights, water activity | Weights unreconciled |
| Deviations and self-inspection | Investigation, correction, owner, closure | Never raised or never closed |
For indoor cultivation, daily records of critical process parameters must be kept and reviewed — two duties, and the second fails more often.
4. Personnel, Training and Hygiene
The guideline requires personnel to “have a high degree of personal hygiene” and training to be recorded — person, procedure version taught, trainer, date. Two duties run in opposite directions: persons with known infectious transmittable diseases must be suspended from areas where they would contact the material, and personnel must equally be protected from contact with toxic or potentially allergenic plant material. Illness reporting, gloves and hair covering are general industry practice, not clause-level requirements. Responsibility must be named — quality system, records, release, training — and designated individuals must supervise collectors.
5. Site and Facility
Medicinal plants “should not be grown in soil or substrate contaminated with sludge, heavy metals, residues,” which obliges you to know previous land use — closed out by a land-use enquiry and baseline soil analysis. A 2020 review in Frontiers in Pharmacology by Park and colleagues notes cannabis hyperaccumulates metals into tissues throughout the plant. Manure “should be thoroughly composted and should be void of human faeces.”
Water, Drainage and Separation of Clean and Dirty Flows
Water “should comply with the country of destination’s regional/ national quality standards,” so the buyer’s standard may govern, not the local one. Buildings used in processing “must be clean” and “must provide adequate protection… against birds, insects, rodents and domestic animals” — sealed rooms, screened openings, bait stations outside product areas, drainage that never carries wash-area run-off into a clean area, and a flow keeping wet incoming material, waste and packed material apart.
6. Seed and Propagation Material
Identity of the starting material is the first thing an auditor checks and the first many farms cannot prove. Seeds “should originate from plants that have been accurately identified in terms of genus, species, variety/ cultivar/ chemotype,” must be “free from pests and diseases,” and should be free from seeds of other species, especially those containing toxic components. Each mother plant needs a unique identifier and a record of source, health, treatments and cuttings — a pathogen or pesticide reaching a mother propagates into every downstream lot.
7. Cultivation Records
The guideline states that “the chosen method of cultivation should be described in a standard operating procedure” — so deviation from it must be recorded and justified. Irrigation and fertiliser logs are contemporaneous, not reconstructed: block, date, product and batch, rate, volume, operator, with nutrient stocks carrying batch numbers so a suspect input traces to every crop that received it. Sensor calibration belongs in the environmental record.
Plant Protection Records and Treatment-to-Harvest Intervals
“Pesticide and herbicide applications should be avoided as far as possible.” Where a product is used, “the application should be carried out only by qualified staff using approved equipment,” and national maximum residue limits must be complied with. Each record carries product, active substance, rate, date, area, operator, and — the field most often blank — the interval between treatment and harvest.
8. Pest Management Under This Framework
Prevention comes first because the alternative is expensive in paperwork, not only in chemicals. Exclusion, sanitation, resistant genetics, scouting and biological control leave a light documentary footprint; every chemical intervention creates a residue, limit, interval and testing question in every destination market. The restricted product list is therefore short — and the Frontiers in Pharmacology review found 84 percent of cannabis samples analysed in Washington state contained pesticides, with up to 24 agents detected.
9. Harvest, Drying, Trimming and Primary Processing
Material should be harvested “at the best possible quality,” “avoiding wet soil, dew, rain, or exceptionally high air humidity.” Cutting devices “must be appropriately cleaned and adjusted,” and harvested material “should not come into direct contact with the soil or floor.” For open-air drying it “must be spread out in a thin layer,” with wood and petrol ovens minimised to limit polycyclic aromatic hydrocarbons.
Water Activity, Moisture and Cleaning Validation
A 2023 review in Frontiers in Microbiology by Gwinn and colleagues states that reducing water activity below 0.7 “prevents the growth of most fungi,” while noting Penicillium and Aspergillus “can survive at aw of 0.62–0.7” — a range the authors call suboptimal rather than safe. Drying duration and final moisture significantly affect fungal levels. Machine parts “must be cleaned after use to ensure that remaining residue does not result in subsequent cross-contamination”; cleaning validation — swabs or visual criteria proving a method removes residue — is general industry practice.
10. Storage and Transport
Packaged dried material “should be stored in a dry, well-aerated building,” with aerated containers advised “to reduce the risk of mould formation or fermentation.” Reusable packaging must be cleaned and dried before use; the label “must be clear, permanently fixed and made from non-toxic material,” carrying material name, lot identifier, quantity, date and status. Segregation separates quarantined, released and rejected material, pest control continues into the store and onto the vehicle, and retention samples are general industry practice.
11. Quality Control and Release
A sampling plan defines the lot, the increments, where they are taken and by whom — sampling from the top of a bag proves only the top of the bag. Thailand’s 2025 framework requires a certificate of analysis per strain covering heavy metals, pesticide residues, pathogenic microorganisms and mycotoxins; California requires a broader panel across eight categories.
| Test | Purpose | Where stated |
|---|---|---|
| Cannabinoids and terpenes | Identity and potency | California panel |
| Moisture content and water activity | Microbial stability of dried flower | California panel |
| Microbial impurities | Pathogenic organisms and total counts | Thai certificate; California |
| Mycotoxins | Toxins persisting after fungal growth | Thai certificate; California |
| Heavy metals | Uptake from soil, water and inputs | Thai certificate; California |
| Pesticide residues | Crop protection residues | Thai certificate; California |
| Residual solvents | Processed goods | California panel |
| Foreign material | Physical contamination | California panel |
Numerical limits differ sharply and must be read from the destination market’s own rules. The Frontiers in Microbiology review shows the gap: action levels for total yeast and mould across United States jurisdictions range from 100 to 100,000 colony-forming units per gram, while the authors propose 10 for species of concern such as Aspergillus and Fusarium. California also requires laboratories accredited to the ISO/IEC 17025 standard, and bars changing a certificate of analysis after issue without the regulator’s permission.
Out-of-Specification Handling and Recall
An out-of-specification result is an event to investigate, not a number to retest until it behaves: quarantine the lot, establish whether it is a laboratory error, extend to lots sharing the same input or period, decide on reprocessing, rejection or destruction, and record the decision with rationale and signature. Recall is the same discipline backwards and depends on traceability — who declares it, who is notified, how shipped quantities are reconciled against recovered ones. The 2023 review notes there are “no proven technologies to degrade or detoxify” mycotoxins once formed.
12. Self-Inspection, Audits and Certification
Self-inspection is the audit you run against yourself on a schedule, with findings, owners, deadlines and documented closure. An auditor does little farming: the pattern is to pick a finished lot and pull the thread — which block, which propagation batch, which mother plant, which spray records, which operators and training records, and whose signature is on the release. Thailand’s scope is stated plainly: the Department of Thai Traditional and Alternative Medicine reviews “soil, water, pesticide use, worker hygiene, and postharvest handling,” with certification reported as valid for one to three years with annual surveillance.
13. The Thai Context
Thailand legalised medical cannabis in 2018, the first in Asia, and in June 2022 the flower came off the narcotics list. Then the Ministerial Notification on Controlled Herbal Medicine (Cannabis), B.E. 2568 (2025), signed 23 June 2025, published in the Royal Gazette 25 June 2025 and effective 26 June 2025, classified cannabis inflorescence as a controlled herb. Cultivation sites holding flower must also hold a sales licence, must meet the cultivation and collection standard or higher — such as the herb-focused agricultural practice scheme or Organic Thailand — and must hold a certificate of analysis per strain. Export requires detailed reports to the licensing authority each time.
Documenting for a Foreign Regulator as Well as a Domestic One
The domestic inspector checks the national scheme; the foreign buyer, and the regulator behind them, checks their own — and the European guideline points outward, requiring irrigation water to meet the destination country’s standards. So specifications, water testing, the restricted product list and the release panel should be written against the strictest market you intend to serve.
14. Realistic Effort and Why First Audits Fail
For a small farm the change is less about equipment than time and habit. Physical work is modest: sealing and screening drying and packing rooms, a lockable input store with segregated zones, drainage fixes, calibrated sensors and scales. The real load is recurring — writing procedures, training against them, completing logs the same day, chasing laboratory results, running self-inspections and keeping the archive retrievable for years. Testing scales with strains and lots, not hectares. The patterns below come from commonly reported field experience, not any published regulatory list.
| Failure pattern | What the auditor sees | Underlying cause |
|---|---|---|
| Back-filled records | Uniform handwriting and ink across weeks | Logs completed at month end |
| Broken traceability | Finished lot cannot reach a mother plant | Identifiers restart each stage |
| Missing intervals | Spray records with no interval to harvest | Field left off the form |
| Retest without investigation | Passing result filed over a failure | No out-of-specification procedure |
Farms fail their first audit not because they grow badly, but because they grew well without writing it down.
Has your farm been through a cultivation standard audit — passed, failed, or still mid-remediation? The community learns more from your specifics than from any guideline summary. What did the auditor open first? Which record did you not have? How long did remediation really take? Quality managers and consultants working across Thai and export-facing sites: which finding do you see repeat, and what fix actually sticks? Please share below.
This article is part of the Asiannabis Community educational series on cultivation standards, testing and export. It is general information, not legal or regulatory advice. Content is for educational purposes within jurisdictions where cannabis cultivation is legally permitted.