Canada's Premium Cannabis Seed Bank | Discreet Shipping
Canada's Premium Cannabis Seed Bank | Discreet Shipping
A seed listing is a spec sheet for a plant that does not exist yet. That is the whole problem. Every number on the page — potency, flowering time, yield, height — describes what somebody else got, from a different phenotype, in a room you have never seen. Cannabis seed descriptions are honest documents when they are written well, but they are predictions, not promises, and most growers read them as if they were promises.
Learning to read cannabis seed descriptions properly is the cheapest skill in growing. It costs nothing, it takes about ten minutes, and it stops you buying a 450 cm (15 ft) sativa for a 1.2 metre (4 ft) tent.
Here is what each field in our cannabis seed descriptions actually measures, where the numbers come from, and which ones deserve your trust.
Many of our cannabis seed descriptions give THC as a band — Mandarin Cookies Autoflower reads High THC (20-24%) — and the rest mostly give one approximate figure, such as “~20%”. The obvious question is “why won’t you just tell me the exact number?”
Because the number does not exist. Not for a seed.
THC content is set by three things working together: the genetics in the seed, the phenotype that particular seed expresses, and how you grow and cure it. A seed carries the genetic ceiling; where you land under it depends on the phenotype you got and on your grow. Two seeds from the same pack, grown side by side by the same person, will not test identically — that variation is the entire reason breeders hunt phenotypes in the first place.
Then there is the measurement problem, which is worse than most people realise. Jikomes and Zoorob analysed 175,136 flower measurements from Washington State’s legal market and found that the median total THC reported for the same class of flower ranged from 17.7% to 23.2% depending on which state-certified lab did the testing. Same product category. Same regulated market. Five and a half percentage points of spread, and the labs that read high on THC read high on CBD too — a systematic tilt, not random noise.
It gets less flattering. A follow-up analysis found that reported THC concentrations bunch up just above the 20% mark — the frequency of results landing immediately above 20% jumped about 43% in Nevada and 17% in Washington. At the two Washington labs whose licences were suspended, the jump was 47%. At the state’s largest lab, it was 1%.
So when a seed listing anywhere quotes “27.4% THC”, it is most likely quoting a single test of a single sample, and the lab alone can move the result by several points. A band is the honest unit. Read the band, assume you will land in the middle of it, and treat anything above the top of it as a good year. That is the only sane way to read the potency line in cannabis seed descriptions.
The CBD field in our cannabis seed descriptions is mostly a ceiling on THC strains (“Low CBD (< 5%)”). On CBD strains the ratio matters more than the absolute figure — we break that down in the CBD cannabis seeds guide.
This field is easy to misread in cannabis seed descriptions, and the usual cause is where the count starts rather than a bad number.
For a photoperiod plant, flowering time is counted from the day you flip the lights to 12/12 — not from germination. Blue Dream at 9–10 weeks means nine to ten weeks after the flip, on top of however long you vegged. Four weeks of veg plus a ten-week bloom is a fourteen-week grow, and the listing only ever showed you ten of them. Cannabis seed descriptions rarely spell that out.
For an autoflower, you have to check which clock the number uses: some listings give only the flowering stretch, others the whole run from seed to harvest.
Those are not the same measurement. An autoflower grows for several weeks before it starts to flower (in university hemp trials, autos were about half in flower by weeks 4–6; see how long cannabis takes to grow), so a bloom-only figure leaves that time out.
On our site, autoflower flowering times are seed to harvest. Most of the fields say so (Moby Dick Autoflower: seed to harvest 10–11 weeks); where a field just gives weeks, the description usually says “from seed”. On any other seller’s listing, look for “from seed” or “seed to harvest” in the field or the description, and if neither is there, ask before you plan around the number.
Then add drying and curing. Drying takes roughly another week or two, and curing comes after that, which appears in nobody’s cannabis seed descriptions — a plant that finishes on schedule is still that far from being smokable. If a hard finish date is what you are shopping for, our roundup of fast flowering cannabis covers the quick finishers we carry.
Yield comes in two different units in most cannabis seed descriptions, and mixing them up produces some wildly optimistic expectations.
Indoor yield is g/m² — grams per square metre of canopy, not per plant. Northern Lights Skunk at 350–450 g/m² (about 1.1–1.5 oz/ft²) does not mean one plant gives you 400 grams (14 oz). It means a fully filled square metre does, whether that square metre holds one big trained plant or four small ones.
Outdoor yield is grams per plant, because outdoors nobody is filling a defined canopy area. Big Bud shows both: 500–600 g/m² indoors, 800–1200 g (28–42 oz) per plant outdoors. Those figures are not in conflict — they are answering different questions.
The second trap is the phrase “up to”. Green Crack lists up to 800 g (28 oz) per plant outdoors, and Super Skunk Silver Haze‘s breeder once gave up to 1500 g (53 oz), a figure its current page puts at about 400 g (14 oz). Those are ceilings: a full season in the right climate, in the ground, with a plant that was never restricted. “Up to” is the best case. It is not the expected case, and cannabis seed descriptions that lead with the ceiling are selling, not informing.
What the yield figure in cannabis seed descriptions genuinely tells you is the strain’s relative productivity. Mandarin Cookies Autoflower at 300–400 g/m² (about 1.0–1.3 oz/ft²) against Jack Herer at 500–600 g/m² (about 1.6–2.0 oz/ft²) is a real difference in the same units, as each listing gives it, even though neither number will be exactly what you get. Use the field to rank strains against each other. Do not use it to forecast your harvest.
Height ranges in cannabis seed descriptions look sloppy until you understand what the width is telling you. The range is the answer, not a dodge.
Big Bud lists 50–225 cm (20–89 in). That is not vagueness — its description gives 50–100 cm (20–39 in) indoors and 200–225 cm (79–89 in) outdoors with space and a full season. Durban Poison‘s listing gives only an outdoor figure, up to 400 cm (13.1 ft), and Super Skunk Silver Haze simply says “up to 450 cm” (15 ft).
A wide range usually spans an indoor plant and an outdoor one given room to grow. A narrow range can mean a genuinely small plant, or just that only one setting was given — so check the description before you read too much into it. That is real information, and it is an easy part of cannabis seed descriptions to skim past. White Widow Autoflower‘s 70–80 cm (28–31 in) is one range, with no indoor or outdoor split. Autoflowers also flower by age, so they cannot be held in veg while you fix a space problem.
Plan against the top of the range, minus whatever your training will realistically take off. Then subtract your light’s hanging height. A 1.5 metre (5 ft) tent gives you roughly a metre (about 3 ft) of usable plant once the fixture and pot are in, which rules out most of the tall sativas and makes something like Gorilla Glue 4 at up to about 137 cm (4.5 ft) a training commitment rather than a drop-in choice.
Every one of our cannabis seed descriptions carries one — 85% Indica / 15% Sativa on Big Bud, 0% Indica / 100% Sativa on Durban Poison. It is the field readers trust most and the one that deserves it least.
The ratio describes reported lineage, not a lab result. Nobody assays a plant and derives a percentage. It is inherited from what the breeder recorded, passed down through crosses, and rounded on the way. When Sawler and colleagues genotyped 81 marijuana samples at 14,031 SNPs, they found only a moderate correlation between genetic structure and reported indica/sativa ancestry: on the main axis of genetic variation, reported ancestry accounted for about a third of the spread (r² = 0.36).
Use the ratio as a rough shape hint and nothing more. Indica-leaning plants are traditionally described as shorter, faster and broader-leafed, and sativa-leaning ones as taller, slower and lankier — a generalisation, not a rule. The effect read is weaker still, which is why we wrote a separate guide to choosing seeds by effect rather than by indica versus sativa, and why the effects described on each listing are worth more of your attention than the ratio.
The Strain Type field (Hybrid, Indica-Dominant, Sativa and so on) is the same information rounded harder, and it turns up in cannabis seed descriptions everywhere for the same historical reasons. And for what the name implies — the Kush, Haze and Cookies families, plus the Auto and Fem suffixes — we have a full strain name decoder.
If you could keep only one field, keep this one. It carries more signal than the numbers in cannabis seed descriptions put together.
The Genetics field gives the cross. Blue Monkey Dick reads Blue Dream x Monkey Dick (Chunky Monkey x Moby Dick) — that tells you where the structure, the vigour and the terpenes are coming from, and it lets you check the parents against strains you have already grown. Frosted Grape Shoes reads Grape Skunk x Cement Shoes. Cannabis seed descriptions that will not name the cross are telling you something by omission.
Our spec block doesn’t have a breeder line, so check the description for who bred the strain (not every one names a breeder). Both of those examples are Mac’s own originals, bred here, which is why we can talk about their selection history at all. Where a line sits in its generations — F1, F2, F4 — changes how much variation to expect across your pack, and we cover that in the seed generations explainer.
The Seed Type field is the other one that changes your whole plan rather than a detail of it — photoperiod or autoflower. Whether a strain is a CBD (or CBG) line shows up in the CBD field and the description instead. If you are still deciding between autoflower and photoperiod, that comparison has its own post.
Grow Difficulty is a relative rating in cannabis seed descriptions, not an absolute one, and it quietly assumes you can supply what the strain wants.
Durban Poison is rated Easy, and its Climate field says “All Climates”. It is also 100% sativa, it can double or triple in size once it flowers, and outdoor plants reach up to 400 cm (13.1 ft). Easy describes how it grows, not how much room it needs: in a short northern season or a low tent, its size works against you. The rating and the height line have to be read together.
Frosted Grape Shoes is rated Moderate and Super Skunk Silver Haze is Moderate as well, for different reasons: one wants attention through a longer bloom, the other gets enormous. Neither is difficult in the sense of being fragile. They just punish a hands-off approach.
Read Grow Difficulty as “how much does this strain forgive?” A first grow should stay on Easy. After that, the field matters less than whether your space suits the plant.
One listing at a time hides how these fields behave across a catalog, so we ran the numbers on all 92 seed listings in our shop as of November 2026: 62 photoperiods and 30 autoflowers. These are listed figures, not lab results, sourced where possible and estimated where not.
| Field | What the 92 listings show | What to take from it |
|---|---|---|
| THC | 52 give one approximate figure (median about 20%), 38 give a band and 2 give neither. Bands run 1 to 10 points wide; the median band is 4 points. | A single figure is not more precise than a band. It is one estimate, so read it as the middle of a spread. |
| Flowering time | Photoperiods: 6 to 14 weeks after the flip, with 45 of 62 inside 8 to 10 weeks. Autoflowers: 8 to 13 weeks from seed to harvest. | The same “8 to 10 weeks” is the bloom alone on a photoperiod and the whole grow on an autoflower. |
| Yield | Every indoor figure is g/m² and every outdoor figure is per plant. 23 indoor and 33 outdoor yields are “up to” ceilings. The top outdoor figure has a median of 600 g (21 oz) per plant on photoperiods and 200 g (7 oz) on autoflowers. | Compare strains in the same unit, and treat “up to” as the best case. |
| Plant height | The top of the range has a median of 150 cm (4.9 ft) on photoperiods and 120 cm (3.9 ft) on autoflowers. 27 of the 56 photoperiods with a height go above 150 cm (4.9 ft); 2 of 30 autoflowers do. 6 photoperiods give no height. | Check a photoperiod’s top figure against your space before anything else. |
| Grow Difficulty | 52 Easy, 5 Easy to Moderate, 34 Moderate, 1 Challenging. No Easy photoperiod flowers past 10 weeks; 8 of 28 Moderate or Challenging ones do. Yet 14 of the 31 Easy photoperiods with a height listed go above 150 cm (4.9 ft). | On photoperiods, Easy tracks bloom length far more closely than plant size. |
Our read: some height fields mix settings, which pulls the top figures up. Big Bud’s 50-225 cm (1.6-7.4 ft) spans indoor and outdoor, and Durban Poison’s 400 cm (13.1 ft) is an outdoor figure. Even so, Durban is not an odd one out on Grow Difficulty: nearly half of our Easy photoperiods list a top height taller than a 1.5 metre (5 ft) tent. In our catalog, an Easy photoperiod lists a bloom of 10 weeks or less, but not necessarily a small plant, so read it next to the height line.
Three things are absent from cannabis seed descriptions everywhere, ours included, and knowing what is missing is part of reading them well.
Which phenotype you will get. A pack is siblings, not clones. Unless a line has been worked for many generations, expect real variation in height, finish time and aroma across the same pack — that variation is the raw material breeders select from, and it is why serious growers buy larger packs. Our pack size guide works through that maths.
How it performs in your conditions. Every number in cannabis seed descriptions came from someone else’s environment. Your light intensity, root temperature, pot volume and watering all move yield, and none of them is on the listing.
What it will taste like to you. The aroma and flavour notes in cannabis seed descriptions are shorthand for what the plant is reported to smell and taste like. They are useful for narrowing a shortlist and useless as a guarantee.
None of that makes cannabis seed descriptions worthless. It makes them a starting position. Browse the feminized seeds or autoflower seeds catalogue with those caveats loaded and you will shortlist far better than someone chasing the biggest THC figure on the page.
Read cannabis seed descriptions in this order: height first, because your space is fixed. Then flowering time, because your season or your patience is fixed. Then genetics, because that is where the honest signal lives. Potency last — it is the field with the loosest measurement behind it and the heaviest marketing pressure on it.
Every good set of cannabis seed descriptions is a well-informed estimate, not a measurement of your plant. Treat cannabis seed descriptions that way and they will steer you well. Treat them as a specification you are owed, and the plant will disagree with you around week six.
If you want the other half of this — matching a shortlist to your particular setup rather than decoding the fields — start with how to choose cannabis seeds for your setup, or work through the rest of our cannabis growing guides.
Shop All Seeds | How to Choose Cannabis Seeds | How Many Seeds to Buy | Growing Guides
Because a seed carries a genetic ceiling, not a fixed potency. The phenotype you get and how you grow, dry and cure it decide where you land under that ceiling. Lab testing adds its own spread on top — state-certified labs testing the same class of legal flower have reported median THC anywhere from 17.7% to 23.2%. A band is the honest way for cannabis seed descriptions to state it.
For photoperiod strains, no — it starts at the 12/12 flip, so add your veg time. For autoflowers it depends on the listing: on our site the figure is seed to harvest (Moby Dick Autoflower, for example, is 10–11 weeks, 75 days from seed); elsewhere, check the listing says which. Then allow roughly another week or two for drying, plus curing time.
Probably not exactly, and that is normal. Indoor figures are grams per square metre of filled canopy, outdoor figures are grams per plant, and anything phrased as “up to” is a best case from ideal conditions. Use the yield numbers in cannabis seed descriptions to compare strains against each other rather than to predict your own harvest.
In cannabis seed descriptions it reflects reported lineage rather than a measurement. Genetic work has found only a moderate correlation between reported indica/sativa ancestry and genetic structure. Treat the ratio as a rough hint about plant shape at most, not as a guide to effect or finish time.
Plant height, against your actual space. It is the one spec that can make a grow impossible rather than merely disappointing, and it is easy to skip in cannabis seed descriptions in favour of the THC band.
Keep reading
How to Choose Cannabis Seeds for Your Setup
How Many Cannabis Seeds Should You Buy? 3-Pack vs 5-Pack vs 10-Pack
8 Myths About Buying Cannabis Seeds OnlineBrowse all our cannabis growing guides by topic, from germination to harvest.
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