Français The highest-THC photoperiod cannabis seeds we carry are Black Runtz (30–32% THC), Banana Sherbet (30%), Fat Bastard (28–30%), Frosted Gelato (27–30%) and Mimosa (24–30%). Below is our full top 10 of the strongest feminized seeds in stock at Quebec Cannabis Seeds, ranked by the top of each listed THC range, with flavour, genetics, flowering time and a picture of each strain. Updated November 2026.
All ten are feminized photoperiod seeds (no autoflowers). Eight are QCS Originals, bred in Quebec by Quebec Cannabis Seeds, the original breeder. Want to compare more strains above 25%? See our full THC cannabis seeds over 25% collection.
The top 10 at a glance
| # | Strain | THC | Genetics | Indoor flowering | Outdoor harvest |
|---|---|---|---|---|---|
| 1 | Black Runtz | 30–32% | Black Diamond Sherbet × Runtz | 8–9 weeks | late September to early October |
| 2 | Banana Sherbet | 30% | Banana × Sunset Sherbet | 8–9 weeks | late September to early October |
| 3 | Fat Bastard | 28–30% | Goldmember × Monkey Spunk | 8–10 weeks | October |
| 4 | Frosted Gelato | 27–30% | Braindamage × Gelato 41 | 9 weeks (63 days) | second week of October |
| 5 | Mimosa | 24–30% | Purple Punch × Clementine | 65–70 days | mid to late October |
| 6 | QC Grape & Cream | 24–30% | Grape Pie × Cookies & Cream | 8–9 weeks | late September to October |
| 7 | White Runtz | 25–29% | Zkittlez × Gelato | 7–8 weeks | late September to early October |
| 8 | Vanilla Frosting | 20–29% | Gelato × Frost OG | 8–9 weeks | late October |
| 9 | Do Si Dos | 25–28% | Girl Scout Cookies × Face Off OG | 8–9 weeks | early October |
| 10 | Fruity Pebbles 2.0 | 25–28% | Granddaddy Purps × (Tahoe OG × Alien Kush) × OG Kush | 55–65 days | late September to early October |
How we ranked them
We ranked strains by the top end of the THC range printed on each QCS product page, and used the bottom of the range to break ties. Only feminized photoperiod seeds are counted. Four strains tie at 25–28% for the last two places (Do Si Dos, Fruity Pebbles 2.0, White Truffle and Gorilla Glue Fast Version); we placed Do Si Dos and Fruity Pebbles 2.0 and list the other two under “Just missed” below. THC percentages are ranges, not promises: phenotype, light, feeding, harvest time and curing all move the result.
1. Black Runtz: 30–32% THC
Black Runtz takes the top spot with 30 to 32% THC on its best phenotypes, in a 70% indica, 30% sativa hybrid from Black Diamond Sherbet × Runtz. Expect an earthy, spicy, berry flavour. At 8 to 9 weeks indoors and a late-September to early-October outdoor harvest, it fits most Canadian seasons better than the later finishers on this list. Quebec Cannabis Seeds is the original breeder of Black Runtz.
| THC | 30–32% |
| Genetics | Black Diamond Sherbet × Runtz |
| Genetic balance | 70% indica, 30% sativa |
| Flavour | Earthy, spice, berry |
| Indoor flowering | 8–9 weeks |
| Outdoor harvest | Late September to early October |
| Seed type | Feminized, photoperiod |
2. Banana Sherbet: 30% THC
Banana Sherbet is listed at 30% THC with a low CBD content, from Banana × Sunset Sherbet. It is indica-leaning (70/30) and tastes of banana, tropical fruit and baked dessert over an earthy base. It flowers in 8 to 9 weeks and finishes outdoors from late September to early October.
| THC | 30% |
| Genetics | Banana × Sunset Sherbet |
| Genetic balance | 70% indica, 30% sativa |
| Flavour | Banana, earthy, tropical fruit, baked dessert |
| Indoor flowering | 8–9 weeks |
| Outdoor harvest | Late September to early October |
| Seed type | Feminized, photoperiod |
3. Fat Bastard: 28–30% THC
Fat Bastard lists 28 to 30% THC, a tight range that makes it a dependable pick. It is a balanced hybrid (half sativa, half indica) from Goldmember × Monkey Spunk, with a skunky, chocolate-and-coffee flavour and a floral finish. Plan on 8 to 10 weeks of flowering indoors; outdoors it finishes in October, so growers in cold regions should have a greenhouse or a plan for late-season protection. Quebec Cannabis Seeds is the original breeder of Fat Bastard.
| THC | 28–30% |
| Genetics | Goldmember × Monkey Spunk |
| Genetic balance | 50% sativa, 50% indica |
| Flavour | Skunk, chocolate and coffee, floral |
| Indoor flowering | 8–10 weeks |
| Outdoor harvest | October |
| Seed type | Feminized, photoperiod |
4. Frosted Gelato: 27–30% THC
Frosted Gelato (Braindamage × Gelato 41) lists 27 to 30% THC, with a narrow range that makes it a predictable pick. The cut leans indica (60/40) and gives cream, vanilla and sweet-candy flavours over an earthy base. Flowering takes about 9 weeks (63 days), and outdoors it is ready in the second week of October. Quebec Cannabis Seeds is the original breeder of Frosted Gelato.
| THC | 27–30% |
| Genetics | Braindamage × Gelato 41 |
| Genetic balance | 60% indica, 40% sativa |
| Flavour | Cream and vanilla, baked dessert, sweet candy, earthy |
| Indoor flowering | 9 weeks (63 days) |
| Outdoor harvest | Second week of October |
| Seed type | Feminized, photoperiod |
5. Mimosa: 24–30% THC
Mimosa crosses Purple Punch with Clementine and lists 24 to 30% THC. The flavour is bright: citrus and pine over grape and sweet candy. It finishes in 65 to 70 days indoors, but outdoors it is a mid-to-late-October harvest, so it is best kept for indoor rooms or protected spaces in colder areas. Quebec Cannabis Seeds is the original breeder of Mimosa.
| THC | 24–30% |
| Genetics | Purple Punch × Clementine |
| Flavour | Citrus, pine, grape, sweet candy |
| Indoor flowering | 65–70 days |
| Outdoor harvest | Mid to late October |
| Seed type | Feminized, photoperiod |
6. QC Grape & Cream: 24–30% THC
QC Grape & Cream comes from Grape Pie × Cookies & Cream and lists 24 to 30% THC. It tastes of grape and berry with cream, vanilla and a touch of spice. Flowering takes 8 to 9 weeks indoors, and outdoor harvest runs from late September into October. Quebec Cannabis Seeds is the original breeder of QC Grape & Cream.
| THC | 24–30% |
| Genetics | Grape Pie × Cookies & Cream |
| Flavour | Grape, berry, cream and vanilla, spice |
| Indoor flowering | 8–9 weeks |
| Outdoor harvest | Late September to October |
| Seed type | Feminized, photoperiod |
7. White Runtz: 25–29% THC
White Runtz (Zkittlez × Gelato) lists 25 to 29% THC and is the fastest finisher in the top ten at 7 to 8 weeks. The flavour mixes sweet candy, cream and vanilla with a hint of diesel and berry. Outdoors it is ready from late September to early October, which makes it one of the safer high-THC choices for short seasons. Quebec Cannabis Seeds is the original breeder of White Runtz.
| THC | 25–29% |
| Genetics | Zkittlez × Gelato |
| Genetic balance | Hybrid |
| Flavour | Sweet candy, cream and vanilla, diesel, berry |
| Indoor flowering | 7–8 weeks |
| Outdoor harvest | Late September to early October |
| Seed type | Feminized, photoperiod |
8. Vanilla Frosting: 20–29% THC
Vanilla Frosting (Gelato × Frost OG) reaches 29% THC at the top of a wide 20 to 29% range, so results vary more from plant to plant than with the narrower-range strains above. It is sativa dominant, with cream, vanilla, floral and sweet-candy flavours. Flowering takes 8 to 9 weeks and outdoor harvest is late October, so it is mainly an indoor or greenhouse pick in Canada. Quebec Cannabis Seeds is the original breeder of Vanilla Frosting.
| THC | 20–29% |
| Genetics | Gelato × Frost OG |
| Genetic balance | Sativa dominant |
| Flavour | Cream and vanilla, baked dessert, floral, sweet candy |
| Indoor flowering | 8–9 weeks |
| Outdoor harvest | Late October |
| Seed type | Feminized, photoperiod |
9. Do Si Dos: 25–28% THC
Do Si Dos (Girl Scout Cookies × Face Off OG) lists 25 to 28% THC. It is mostly indica, with baked-dessert, earthy and floral flavours. It flowers in 8 to 9 weeks and finishes outdoors in early October.
| THC | 25–28% |
| Genetics | Girl Scout Cookies × Face Off OG |
| Genetic balance | Mostly indica |
| Flavour | Baked dessert, earthy, floral |
| Indoor flowering | 8–9 weeks |
| Outdoor harvest | Early October |
| Seed type | Feminized, photoperiod |
10. Fruity Pebbles 2.0: 25–28% THC
Fruity Pebbles 2.0 combines Granddaddy Purps with a Tahoe OG × Alien Kush cross and OG Kush, and lists 25 to 28% THC. It is nearly balanced (55% indica, 45% sativa) with a berry and tropical-fruit flavour. At 55 to 65 days indoors it is one of the quicker finishers, and outdoors it is ready from late September to early October. Quebec Cannabis Seeds is the original breeder of Fruity Pebbles 2.0.
| THC | 25–28% |
| Genetics | Granddaddy Purps × (Tahoe OG × Alien Kush) × OG Kush |
| Genetic balance | 55% indica, 45% sativa |
| Flavour | Berry, tropical fruit |
| Indoor flowering | 55–65 days |
| Outdoor harvest | Late September to early October |
| Seed type | Feminized, photoperiod |
Buy Fruity Pebbles 2.0 seeds →
Just missed the top 10
- White Truffle: 25–28% THC
- Gorilla Glue Fast Version: 25–28% THC
- Lemon Runtz: 23–28% THC
- QC Amnesia Gas: 22–28% THC
Tips for getting the most from high-THC photoperiod plants
- Match the strain to your season. Vanilla Frosting, Mimosa and Fat Bastard finish in October, so in short Canadian seasons they suit indoor rooms or a greenhouse. White Runtz, Black Runtz and Fruity Pebbles 2.0 are safer outdoors.
- Give strong, even light and keep the room stable. Heat stress lowers potency and terpenes.
- Harvest on trichomes, not the calendar. Most growers harvest when the trichomes are mostly cloudy.
- Dry slowly and cure in jars. A slow dry and a few weeks of curing protect both flavour and potency.
Why buy high-THC seeds from Quebec Cannabis Seeds?
- Bred in Quebec by the original breeder. Eight of these ten strains are QCS Originals, bred here since 2015 by a grower with 35+ years of experience.
- Guaranteed. 80% germination guarantee with replacements, and delivery guaranteed. If a pack under-performs, email us and we make it right.
- Free seeds with every order, and free shipping on orders over $200.
- Fast, discreet shipping. Ships from Quebec within 24 hours Monday to Friday in plain, unbranded packaging, to Canada (Canada Post) and to the USA (1–2 business days by Express).
- Real support. Every email answered within 24 hours.
Shop all seeds over 25% THC → Canada delivery Shipping to the USA
High-THC cannabis seeds: frequently asked questions
What is the highest THC cannabis seed you sell?
Black Runtz has the highest listed THC of our photoperiod seeds, at 30 to 32%. Banana Sherbet (30%) and Fat Bastard (28 to 30%) follow. These are the ranges shown on each QCS product page; real THC depends on the phenotype and how the plant is grown.
How much THC will these seeds actually produce?
The ranges are what growers can reach on good plants under good conditions, not a guarantee. Lighting, nutrition, harvest timing, drying and curing all change the final number, and a lab test is the only way to know a specific batch.
Are these autoflowers or photoperiod seeds?
All ten are feminized photoperiod seeds. Indoors you switch to 12 hours of light and 12 hours of darkness to trigger flowering; outdoors they flower as the days shorten in autumn. Autoflowers are not included in this list.
Does a higher THC percentage mean a stronger high?
Not always. Terpenes, minor cannabinoids and your own tolerance all shape the effect. If you are new to cannabis, start with a lower dose even from a high-THC strain.
Which high-THC strain finishes fastest?
White Runtz (7 to 8 weeks indoors, 25 to 29% THC) and Fruity Pebbles 2.0 (55 to 65 days, 25 to 28% THC) are the quickest finishers in the top ten.
Which of these are QCS Originals?
Eight of the ten are bred by Quebec Cannabis Seeds, the original breeder: Fat Bastard, Black Runtz, Frosted Gelato, Mimosa, QC Grape & Cream, White Runtz, Vanilla Frosting and Fruity Pebbles 2.0. Banana Sherbet and Do Si Dos are classic genetics that we stock.
Do you ship these seeds across Canada and to the USA?
Yes. Orders ship from Quebec within 24 hours Monday to Friday in plain, unbranded packaging, to Canada by Canada Post and to the USA by Express. Please check the laws where you live before ordering.
How do I get the most THC from my plants?
Start with the right genetics, give strong light and a steady feed, harvest when the trichomes are mostly cloudy, and dry and cure slowly. Stress, heat and rushed drying all lower quality.
A note on the numbers in this article: harvest dates, flowering times and yields are ranges, not promises. They vary depending on growing conditions: the grower, the method and the season's weather. No strain is 100% mold resistant. How we set these numbers →
About this article
Published by the Quebec Cannabis Seeds team. QCS was founded in 2015 by Trent LaPierre, a Quebec breeder with more than 35 years of hands-on growing experience. Genetics we bred ourselves are described from our own breeding work; when a strain comes from another breeder, we say so and credit them. How we work. Last updated: November 6, 2026.
Sources and further reading: Cannabis Act (Justice Laws, Government of Canada) · Cannabis Regulations (SOR/2018-144). Rules on cannabis seeds differ by province and state; check your local regulations before ordering.
