What You May Legally Spray Under Thai GACP, and Why There Is No Cannabis-Specific Product List

🌱 Cultivation Pesticide & Contaminant Remediation
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As of October 2026, Thailand’s GACP standard for cannabis says three things about pests. Only organic substances or biological products may be used against them. Integrated pest management is mandatory. Chemicals may not be used to prevent or eliminate pests. The standard does not include a cannabis-specific list of named products that meet these rules. Because of that gap, a question like the member question on harmful residues (topic 871) gets a discussion instead of a clear answer.

1. What the Thai GACP standard says

These points come from the DTAM notification on the good agricultural and collection practice standard for cannabis, B.E. 2566 (2023). We read it in a copy of the Thai text shared online and in a third-party English translation:

  • Only “organic substances or biological products” may be used to prevent and control pests, “in accordance with the law” (clause 9.5).
  • IPM is mandatory, and chemicals may not be used to prevent and eliminate pests (clause 9.3).
  • Agricultural hazardous substances banned under the Hazardous Substances Act B.E. 2535 may not be used or kept (clause 9.6).
  • Soil, substrate and water must be sampled for residues and heavy metals before planting. The Thai text we read says “at least once” (clauses 5.2 and 6.1). Some English renderings say “before every planting cycle”, which is stricter than the Thai wording. If your auditor sets a higher frequency, follow it.

We read the Thai wording from a shared copy, not from the Royal Gazette or DTAM’s own site, and the standard may have been revised since. Anyone making a commercial decision should check the current text with DTAM.

2. Reading the rule precisely

It is a permissive rule, not a prohibitive one. It does not list banned compounds. It names a category of what is allowed. That is harder to comply with: with a banned list you can check a product, but with a permitted category you must show that your product belongs to it.

The text names no certification scheme and no product list for “organic or biological”. A grower holding a bottle has to make a judgement.

“Do not use chemicals” cannot be read literally. Everything is a chemical, including water and neem oil. In context, the clause is aimed at synthetic crop-protection chemistry. But boundary cases are where money is lost: a mineral fungicide, an inorganic salt such as potassium bicarbonate, a horticultural oil, an insect growth regulator of natural origin. The text does not settle these, and we will not pretend it does.

3. Two filters: Thai registration and GACP

The words “in accordance with the law” matter. Pesticide products made, imported or sold in Thailand fall under the Hazardous Substances Act and must be registered with the Department of Agriculture (DOA). That rule covers biological and botanical formulations sold as pest control, not only synthetic ones. If you are unsure whether a particular living biocontrol agent needs registration, ask the DOA.

So a product has to pass two separate tests:

  1. It is legally registered for use in Thailand. Check the registration number on the label against DOA records, or ask the DOA.
  2. It falls inside “organic or biological” under GACP.

Growers also have national reference points. The DOA’s records cover registered biocontrol and biopesticide products. The Thai organic agriculture standard, TAS 9000 (the basis of Organic Thailand certification), includes lists of permitted inputs. Neither one is a GACP-approved list. A registered product can be fully synthetic. An input that appears on an organic list is useful evidence for your audit file, not a guarantee that your auditor will accept it.

4. What is clearly inside the category

Biological control agents, meaning living organisms. Predatory mites, parasitoid wasps, predatory beetles. Check species choice against your temperatures: Thai growing rooms often run above 30 °C.

Microbial pesticides. Bacillus thuringiensis for caterpillars is the clearest example. Thai agricultural biologicals suppliers sell Bt products, so a domestic supply channel exists.

Microbial root products. Trichoderma, Gliocladium and Bacillus preparations. A 2024 greenhouse paper assesses RootShield HC, Asperello and Prestop, but it gives no efficacy percentages for any of them.

Root-applied silicon. There is published evidence that it suppresses powdery mildew on hemp.

Botanical oils, mainly neem. Widely used and widely accepted as organic, with the caveat covered in section 6.

5. No cannabis-specific GACP list

We searched for a published list of crop-protection products accepted for cannabis under Thai GACP and could not find one. National registers exist, but nobody has published a cannabis-specific GACP list.

In practice, you cannot check a product against a GACP list. You have to decide whether it fits “organic or biological”, use it, and then learn at the audit or the laboratory whether you were right. The worst outcome is finding a residue on a certificate of analysis for a crop that is already harvested. At that point your options are poor and expensive.

The stakes do not stop at your own licence. Under the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis) B.E. 2568, flower that is sold or exported must come from a GACP-certified cultivation site. If a site loses certification, licences further down the chain, such as dispensary and export licences, can be suspended. A residue problem at a farm is a commercial problem for its buyers.

The rules may change. The Cannabis Control Act is still a draft: the Cabinet approved it on 22 September 2026 and sent it to the House. If it is enacted, it could change the rules on cultivation inputs.

6. How to work without a list

These are our recommendations for handling an open compliance question. They do not replace an official answer.

Ask DTAM directly and keep the answer in writing. A written answer from the regulator about a specific product counts for more than forum consensus, and it is evidence at your next audit.

Ask your certifying auditor before you spray. Asking “would you accept this product?” before you spray costs nothing. Ask it after you have sprayed and you have a finding.

Keep a written input register from day one, whether or not you are certified yet. Record the product, its DOA registration number, active ingredient, batch, rate, date, crop stage, who applied it, and why. A farm with a complete register can demonstrate compliance. A farm without one cannot, even if it did everything correctly.

Prefer living organisms over sprayed substances where both would work. A predatory mite release leaves no residue to detect, and it matches what the standard expects IPM to look like.

Test water and substrate before planting, and read the results as information about your site, not just paperwork. We could find no published survey of Thai irrigation water quality by province, so your own test may be the only data for your site.

Do not assume that “natural” means compliant. Neem is the example. It is botanical, but azadirachtin is a detectable compound that appears on some pesticide panels in some jurisdictions. Whether neem is acceptable under Thai GACP and whether it is within limits in your destination market are separate questions. We cannot answer the first. It is the question to put to your auditor.

Assume the export market is stricter than the domestic rule. For flower going to Germany or Australia, the residue panel that applies is the destination’s, not Thailand’s.

7. The short version

  • GACP allows only organic or biological inputs, but there is no cannabis-specific list of products that qualify.
  • Any product must also be legally registered with the DOA. DOA records and the TAS 9000 input lists are useful references, but they are not GACP approval.
  • Living organisms are the safest choice. Get boundary products cleared in writing before you use them.
  • Your input register proves compliance. The destination market’s residue panel decides whether a batch sells.

If you grow on a GACP-certified site in Thailand: which inputs have you used and had accepted at audit? A list built from growers’ experience is the most useful thing this thread could produce.

Moderation note: share your own experience only: the product, what you used it for, and whether the auditor accepted it. No sales links, prices or contact details. Replies must follow the advertising rules in topic 1293. Posts that advertise or offer cannabis flower will be removed.

Related reading: the member question on harmful residues (topic 871); the forum’s IPM topic 1301; the forum’s GACP topic 1317.

This article is a reading of published guidance as of October 2026 and is not legal or regulatory advice. On what is permitted under Thai GACP, the authorities are the Department of Thai Traditional and Alternative Medicine and your certifying auditor. On product registration, the authority is the Department of Agriculture. Cannabis flower is a controlled herb in Thailand under the Notification of the Ministry of Public Health Re: Controlled Herbs (Cannabis) B.E. 2568. Cultivation and sale require licensing, and flower may not be sold or advertised online. Check anything here against the current Thai-language text before acting on it.

Sources

Further reading on Asiannabis

100% Organic Pest Control: Neem Oil Plus Beneficial Insects — and Where the Book's Advice Needs Updating