One species, several jobs
Hemp and drug-type cannabis are the same species, Cannabis sativa L. People have selected it for different traits for thousands of years, so plants grown for different purposes can look and behave very differently.
- Fibre
- Tall, sparsely branched plants grown close together for their stalks. The outer fibre goes into textiles and rope, and the woody core into building materials and bedding.
- Seed and oil
- Plants selected for seed yield. Hulled seed is a food, and the oil is pressed for food and body-care uses.
- Cannabinoid types
- Shorter, heavily branched plants grown for their flowers and the compounds in them, mainly CBD or CBG. This is the area Ridge Research NZ works in.
- THC-dominant (drug-type)
- Plants bred to produce high levels of THC. In New Zealand these plants and their seeds are controlled drugs, whatever they are grown for.
The compounds
Cannabinoids are chemicals made in the plant’s resin glands. More than a hundred have been identified, but three matter most for hemp breeding.
| Compound | What it is | Why it matters here |
|---|---|---|
| THC tetrahydrocannabinol |
The main intoxicating cannabinoid. | It defines hemp in law. Above the legal limit, a plant is no longer hemp. |
| CBD cannabidiol |
A non-intoxicating cannabinoid, and the most common one in cannabinoid-type hemp. | The main target of many hemp breeding programmes. |
| CBG cannabigerol |
A non-intoxicating cannabinoid, usually present only in small amounts. | Rare to find as the dominant compound, which makes CBG-rich plants a distinctive breeding goal. |
Plants make most cannabinoids first as acid forms (THCA, CBDA, CBGA), which change to the compounds above when heated or aged. CBGA is the common starting point: enzymes convert it into the THC or CBD acid forms. A plant is CBG-dominant when that conversion is mostly blocked, so CBGA builds up instead.
Terpenes are the aromatic compounds that give plants their smell. They are measured alongside cannabinoids, because the combination of the two is what makes one plant’s chemistry distinctive.
Why chemistry matters in breeding
Plants are grouped by chemotype, meaning which cannabinoid dominates. The usual groups are THC-dominant, mixed THC and CBD, CBD-dominant, CBG-dominant, and fibre or seed types with very little of any of them.
The balance between THC and CBD is controlled largely by one gene with two versions that act together. Cross a CBD-rich plant with a THC-rich one and the offspring land in between. A breeder working with hemp therefore has to track THC in every generation, because one cross can push a line over the legal limit.
Growing conditions also influence cannabinoid levels, so a vendor’s stated figures are a starting point, not a guarantee. That is why we rely on laboratory results from our own plants, grown at our own site.
You will also see plants labelled “indica”, “sativa” or “hybrid”. These are market names. They do not reliably predict a plant’s chemistry, so we describe plants by measured cannabinoid and terpene profile instead.
New Zealand rules at a glance
Based on official guidance current at 3 November 2026. Rules change, so check the official pages below before acting on anything here. This is not legal advice.
- The definition. Hemp is Cannabis sativa with no more than 1% THC by dry weight. This applies to any part of the plant, including harvested seed. These rules took effect on 28 May 2026 and replaced the old licensing scheme.
- Above the limit. Cannabis plants, clones and seeds above 1% THC are not hemp and remain controlled drugs.
- Breeding and research. No industrial hemp licence is needed to breed cultivars or research their suitability.
- Notification. Anyone growing hemp must notify both NZ Police and the Ministry for Primary Industries before cultivating. Each notification lasts one year.
- Import and export. Whole seed and plant material still need a licence to cross the border. Finished hemp products such as stalk and hulled seed do not.
- Medicinal cannabis. Products made and used as medicines are a separate regulated area, run by Medsafe.
Official sources: Ministry of Health: hemp, NZ Police: cultivating hemp.
Quick glossary
- Cannabinoid
- A chemical compound made by the cannabis plant, such as THC, CBD or CBG.
- Chemotype
- A plant’s chemical profile: which cannabinoids and terpenes it makes, and in what amounts.
- Cultivar
- A named, cultivated variety bred for particular traits, the plant equivalent of a breed.
- Precursor
- A compound the plant converts into another. CBGA is the precursor of the THC and CBD acid forms.
- Terpene
- An aromatic compound that gives a plant its scent, also found in many other plants such as citrus and pine.
Questions about the research
If you work in plant breeding, trial design, laboratory testing or regulation, we would like to hear from you. We do not sell seed, plants or any other product.
hello@ridgeresearch.co.nz