An heirloom (or heritage line) is a seed line that has been maintained and passed on by growers over many generations, typically decades, without being crossed into new hybrids. In cannabis it usually means landrace or early-hybrid material that left its source region, often in the 1960s to 1980s, and has been kept going by successive growers since.
In practice
Heirlooms are a key reservoir of older genetics. Seed stock of 50 to 70 years old, kept and regrown carefully, can still test in the high 20s for total cannabinoids, which is direct evidence that the genetics were never weak.
Keeping an heirloom honest means open pollination with enough plants each generation, isolation from other pollen, and records of who kept it and when. Seed from a handful of parents each time narrows the line through genetic drift; crossing it to a modern hybrid ends it as an heirloom, whatever the label says.
Don't confuse with
- Landrace: maintained in its region of origin by local farmers; an heirloom may descend from one.
- Clone-only: a single genotype kept by cuttings; an heirloom is a seed population.
- "Classic" or "OG" (marketing): often hybrids under an old name.
A hybrid is the offspring of two genetically different parents; almost all modern cannabis is hybrid, built from crosses between landrace-derived and other lines.A landrace is a traditional, locally adapted cannabis population kept by farmers in one region over many generations, with its own type and plenty of internal variation.Total cannabinoids is the sum of all cannabinoids a lab measured in a sample, usually reported in % w/w, with acid forms either summed raw or decarboxylation-adjusted.Open-pollinated seed comes from a population left to cross freely among its own plants, without controlled pairs, which keeps a line's variation and type over generations.Genetic drift is random change in allele frequencies between generations of a seed population, strongest in small populations; clones do not drift this way.A clone-only is a cultivar that exists only as cuttings from one original plant, with no seed line that reliably reproduces it.The genotype is the set of alleles a plant actually carries, either at one locus or across its whole genome, as opposed to the traits you can see.OG is a cannabis family name tied to a group of influential clone-only cultivars from the 1990s, and general slang for "original" or long-established.An accession is a distinct sample of plant material (seed, tissue or cuttings) entered into a collection or gene bank under its own ID with records of origin.The gene pool is the total set of alleles present in a population, cultivar group or species; a narrow gene pool limits what breeders can select from.A seed run is a dedicated grow in which selected parents are crossed to produce a batch of seed, as opposed to growing for flower.
