One Tent, Two CBD Packs
Place two packs of CBD seeds next to each other, one labelled 1:1 and the other 20:1, and the two look identical: same breeder’s packaging, the same seed count, contents that no eye can tell apart. Run them side by side and they part ways from the first step and do not meet again. The reason is a single gene, and the easiest way to understand what it does is to track the two packs along each stage both share: the cross that produced them, the seed, the seedling, the flowering tent, the harvest, the jar, the lab bench and the law. The lines quoted as reference points below are taken from the range at https://calmcbdseeds.com, and that range goes 1:1, 2:1 and 20:1 with a top line at about 30 to one; the genetics is the same regardless of which shop the seeds come from.
How Each Pack Was Made
Cannabis settles whether it is going to produce THC or CBD at one locus on the genome. The gene there exists in two forms: one builds the enzyme that converts the common starting molecule into THCA, the other the enzyme that turns it into CBDA. Each plant holds two copies, one received from each parent, and the pair sets 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 versions are codominant and neither overrides the other.
The balanced pack was made by pairing two balanced plants, both holding one copy of each version. The 20:1 pack was made by crossing two plants that each carry two CBD copies and no THC copy in either of them. This one difference at the cross determines everything afterwards, and the difference is fully inside the seed long before it is packed.
What the Pack Actually Holds
Cross two balanced plants and the seeds fall out by the oldest arithmetic 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 means, on average, around two THC-dominant seeds, two or three CBD-dominant seeds, and five true balanced ones. The pack is sold by its parents, and in the case of half its seeds the label fits; in the case of the other half it is a description of something else. Calm CBD Seeds states the expected split on every balanced pack, which means the buyer sees before sowing that a share of the plants are going to differ from the headline ratio.
The 20:1 pack has no such spread. Each seed received a CBD copy from both parent, every plant is going to be CBD-dominant, and the ratio on the foil applies to all of them, give or take the ordinary differences in how total cannabinoid any given plant produces. The trade say such lines “breed true” for chemotype; the phrase refers to precisely this lack of variation.
Where Nothing Shows
Here the two packs appear the same again, and the resemblance holds longer than most growers expect. Chemotype shows no trace on a seedling. Leaf shape, vigour, internode length and the speed of growth rate are governed by different genes entirely, and the three chemotypes of plant in the balanced pack come up indistinguishably beside one another and from every plant in the 20:1 pack.
One practical distinction at this stage comes from ancestry rather than chemotype. Strains with recent hemp ancestry, which includes a number of older CBD-dominant lines, are inclined to grow rangier and fill out more sparsely. A heavily selected 20:1 strain grows like a normal modern hybrid; a young one may still shows the field in its frame. Not one of these tendency tells anything about the ratio in the flower.
When the Resin Comes In
In flower the two packs start to offer hints, and most of them mislead. Trichome coverage is the first thing a grower judges, and it was a reasonable rule: early CBD-dominant lines showed markedly less frost than their THC counterparts, a inheritance from hemp. Current selections have largely erased that gap, and a less frosted plant from the 20:1 pack may perfectly well test exactly where the foil promised. Resin density and chemotype are carried separately.
Smell is an even poorer guide. The terpene chemistry lives on yet different genes, so the THC-dominant plant sitting in the balanced pack can be indistinguishable to the balanced one next to it, and both can be indistinguishable to a plant from the 20:1 pack. Growers who try to sort a balanced pack by nose in week eight are right about half the time, and that is not any better than not unsorted at all.
One Place CBD Is More Forgiving
Here the two packs differ in a manner that benefits the grower of the 20:1 pack and the CBD-dominant plants hidden in the balanced pack. CBDA breaks down rather slowly than THCA, so a CBD-dominant plant allowed a week past its peak retains most of its cannabinoid load, whereas a THC-dominant one in the same neglect has already started shedding THC to CBN. The cloudy guidance nonetheless holds; it holds on account of the terpenes, which degrade on every plant whatever the chemotype, and a late, rushed CBD flower smells of very little whatever the lab number is.
What Mixing Does
The 20:1 pack goes into one jar. Every plant in it carries roughly the same ratio, and mixing them changes nothing anyone would measuring. The balanced pack should never be treated that way. Blend its 10 plants in a single jar and the contents is a mixture that no foil ever promised, weighted by which plants grew biggest, and no later test can untangle the plants that went in.
The discipline that prevents the grief is almost tedious: cut the balanced pack plant by plant, cure each separately, label them, and test them plant at a time before the crop is combined. This is the one stage in the entire grow at which the different kinds of plant in the balanced pack can still be kept apart without a lab, and then only for the reason that each is still in its own container.
Stage Seven: The Lab Report
Submit a few grams from every jar to a laboratory and the two packs at last are legible. For the 20:1 pack the reports arrive back clustered tightly around the advertised ratio, varying mainly in total output not in balance. For the balanced pack they come back in three groups: some plants with almost all THC, some with nearly all CBD, and the rest sitting around one to one. Nothing of this result is a failure; it is the breeder’s cross expressed as numbers.
Over-the-counter test kits are sold for growers who cannot reach a lab, and the majority of them detect whether THC is there but not how much. That is sufficient to separate the THC-dominant jars away of a balanced pack and not enough to assign a ratio to the rest, and that matches the commonest use: finding out which of the 10 jars will catch out a guest.
Where the Law Reads the Numbers
The last place at which the two packs separate is in law, and it catches growers who thought “CBD” meant “hemp”. Most jurisdictions classify hemp by a THC limit, a small fraction of a percent of dry weight, and the exact figure varying from country and sometimes over time. A plant from the 20:1 pack producing twenty percent CBD at twenty to one also produces about one percent THC, which is many times over the majority of thresholds. Certified hemp lines are selected to hold total cannabinoid content low so the THC share stays below the line at harvest; CBD flower lines are selected for rich content and allow the THC rise with it. A seller that offers only a ratio is selling a flower line; a grower who needs a compliant crop should look for a tested THC figure at maturity and buy no line that cannot show one.
Beyond the threshold question, the chemotype changes very little in the law on the seed as such. In places where holding cannabis seeds is lawful and germinating them is not, the balanced pack and the 20:1 pack fall under the same rule as every other pack. Where the plant is legal outright, the choice between them is the grower’s and nobody else’s. None of this page is legal advice, and the law which counts is the one where the seed is going to be grown, rather than the one in the place it was bought.