Place two packs of CBD seeds next to each other, one marked 1:1 and the other 20:1, and the two look the same: the same brand foil, the same seed count, contents that no eye can tell apart. Run them side by side and they go their separate ways from the very first step and never meet again. The cause is a single gene, and the easiest way to see what it does is to track the two packs through every step they go through: the cross that produced them, the seed, the seedling, the flower tent, the harvest, the jar, the lab bench and the border. The lines quoted as reference points throughout are taken from the range at https://calmcbdseeds.com, which runs 1:1, 2:1 and 20:1 and a highest line at around 30 to one; the genetics holds the same regardless of which shop the seeds came from.
Before the Seed Exists
Cannabis settles whether it is going to make THC or CBD at one locus on the genome. The gene there exists in two forms: one builds the enzyme that converts the common precursor into THCA, the other the enzyme that converts it into CBDA. Each plant carries two copies, one received from each parent, and the pair fixes the chemotype. Two THC copies give a THC-dominant plant. Two CBD copies make a CBD-dominant one. One of each makes a balanced plant, because the two forms are codominant and not one of them silences the other.
The balanced pack was made by crossing two balanced plants, both holding one copy of each version. The CBD-dominant pack was bred by crossing two plants which each carry two CBD copies and no THC copy between them. This one difference at the bench determines everything afterwards, and the difference is fully inside the seed before it is put in the foil.
What the Pack Actually Holds
Cross two balanced plants and the seeds fall out by the oldest rule in genetics: a quarter get two THC copies, a quarter inherit two CBD copies, half get one of each. In a pack of 10 seeds that works out to, on average, two or three THC-dominant seeds, two or three CBD-dominant seeds, and five true balanced seeds. The pack is labelled by its parents, and for half its contents the label fits; in the case of the other half it does not. Calm CBD Seeds prints the expected split on each balanced pack, which means the buyer sees before planting that a share of the plants will differ from the headline ratio.
The CBD-dominant pack has no such split. Every seed got a CBD copy from each parents, every plant will be CBD-dominant, and the ratio on the foil holds to every one of them, give or take the ordinary differences in the amount of total cannabinoid an individual plant produces. Breeders describe such lines « breed true » for chemotype; the phrase refers to exactly this lack of surprise.
Weeks One to Four
Here the two packs look alike once more, and the likeness lasts further than many growers assume. Chemotype shows no trace on a seedling. Leaf shape, colour, stem length and growth are controlled by other genes altogether, and the different kinds of plant in the balanced pack grow without any visible difference from one another and from each plant in the CBD-dominant pack.
The one real difference during this stage comes from ancestry not chemotype. Lines with recent hemp ancestry, which includes a number of older CBD-dominant strains, are inclined to grow taller and fill out more sparsely. A heavily selected 20:1 strain behaves like a normal modern hybrid; a young one may still carry the field in its frame. Not one of these habit says a thing about the ratio to come.
Frost, Smell and the Wrong Conclusions
In flower the two packs begin to give hints, and the majority of the clues point the wrong way. Trichome coverage is the first one a grower judges, and it was a fair guide: first-generation CBD-dominant strains carried markedly less resin than their THC counterparts, an unwanted inheritance from hemp. Modern selections have largely closed that gap, and a less frosted plant from the CBD-dominant pack can perfectly well come in precisely where the foil said. Resin density and chemotype are inherited separately.
Smell is an even poorer guide. The terpene chemistry lives on yet other genes, so the THC-dominant plant hiding in the balanced pack can smell indistinguishable to the balanced one next to it, and both can be identical to a plant from the CBD-dominant pack. Growers who attempt to separate a balanced pack by nose at week eight are guessing, which is no better than leaving the plants sorting at all.
Stage Five: The Harvest Window
Here the two packs differ in a manner that benefits the grower of the CBD-dominant pack and also the CBD-dominant plants hidden in the balanced pack. CBDA degrades more gradually than THCA, so a CBD-dominant plant allowed a week beyond its peak retains the bulk of its cannabinoid load, where a THC-dominant one in the same neglect has by then started shedding THC into CBN. The usual trichome rules still applies; it applies on account of the terpenes, which fade on every plant regardless the chemotype, and a late, rushed CBD flower smells of little however good the test result is.
What Mixing Does
The CBD-dominant pack goes into one jar. Each plant in it carries roughly the same ratio, and mixing them changes nothing anyone would measuring. The balanced pack cannot be treated that way. Blend its 10 plants in a single jar and the result is a ratio that nobody’s foil ever promised, weighted by whichever plants yielded biggest, and no later test can untangle what went in.
The habit that prevents the grief is almost tedious: harvest the balanced pack plant by plant, dry each separately, number them, and test them plant at a time rather than after the crop is mixed. It is the one point in the entire process where the different kinds of plant in the balanced pack can yet be told apart short of a lab, and only because each is at that moment in its own container.
Reading the Two Results
Submit a sample from each jar to a laboratory and the two packs finally are readable. For the CBD-dominant pack the certificates arrive back clustered closely near the advertised ratio, differing mostly in total output not in balance. For the balanced pack they come back in three groups: some reports showing nearly all THC, a few showing nearly all CBD, and the majority sitting around one to one. No part of this pattern is a defect; it is the breeder’s cross expressed as numbers.
Over-the-counter test kits are sold for growers without a lab, and the majority of them show whether THC is there but not how much. That is enough to pull the THC-dominant plants away from a balanced pack and insufficient enough to assign a ratio to the rest, which suits the commonest use: finding out which of the 10 jars is going to catch out a guest.
Stage Eight: The Border
The last stage where the two packs separate is in law, and it trips growers who thought « CBD » meant « hemp ». Most countries classify hemp by a THC limit, a small fraction of a percent of dry weight, with the precise number differing by country and sometimes year to year. A plant from the CBD-dominant pack making twenty percent CBD at twenty to one also makes about one percent THC, which is many times above most thresholds. Compliant cultivars are bred to hold total cannabinoid output down so the THC share stays under the line at harvest; CBD flower lines are bred for high output and let the THC rise with it. A shop that gives only a ratio is describing a flower line; anyone who needs a legal hemp crop should ask for a tested THC figure at maturity and order nothing that cannot show one.
Past the threshold issue, the chemotype changes nothing about the law on the seed itself. Where holding cannabis seeds is permitted and germinating them is not, the balanced pack and the CBD-dominant pack sit in the same rule as every other pack. In places where the plant is legal without restriction, the decision between them is the grower’s and nothing else’s. None of this article is legal advice, and the rule which applies is the one in the place the seed is going to be grown, not the one where it was sold.