MK-Ultra
Cannabis seeds
by T.H. Seeds
MK-Ultra Feminised Seeds — Double Cannabis Cup Winner by T.H. Seeds
MK-Ultra feminised seeds are an indica-dominant cannabis strain from T.H. Seeds that crosses the legendary G-13 mother with an OG Kush male. The result is a compact, resin-drenched plant that took 1st place at the 2003 High Times Cannabis Cup and came back for 2nd in 2004. At 100–120cm tall with a flowering time of just 56–63 days, this is one of those strains that punches well above its height class — dense, golf-ball-sized buds coated in sticky trichomes, a fresh pine aroma that fills the room the moment you open the jar, and a stimulating, immediate effect that hits before you've set the lighter down.
MK-Ultra Feminised Seeds — 3-Pack or 5-Pack?
MK-Ultra feminised seeds come in packs of 3 or 5. The choice depends on your setup and how committed you are to the genetics.
| Pack Size | Best For | Notes |
|---|---|---|
| 3 seeds | Test runs, small tents, first-time growers trying the genetics | Enough to fill a 60x60cm tent or run a small pheno hunt |
| 5 seeds | SOG setups, dedicated grows, anyone who knows they want a full canopy | MK-Ultra performs best in SOG at 18–20 plants per m² — you'll need multiples of the 5-pack for a proper run |
If you're planning a Sea of Green — and that's honestly the best way to run this strain — go straight for the 5-pack. The 3-pack works if you want to test the genetics in a smaller space before scaling up. One thing to keep in mind: at 18–20 plants per square metre, a single 5-pack is a starting point, not the finish line.
Why MK-Ultra Feminised Seeds Deserve a Spot in Your Grow Room
There are plenty of indica strains that promise dense buds and heavy resin production. MK-Ultra actually delivers — and it does so in a plant that barely reaches 120cm. You don't need a cathedral ceiling or months of patience. The G-13 genetics bring serious resin production (the urban legend says G-13 escaped from a US government research facility — take that with a grain of salt, but the trichome coverage is very real). The OG Kush father adds structural density and that unmistakable fresh pine flavour that cuts through even a room full of other strains.
What we like most about MK-Ultra feminised seeds is the predictability. The plants stay compact, the internodal spacing is tight, and the buds stack up like little green golf balls along every branch. Flowering wraps up in 56–63 days — that's fast for a strain with this kind of resin output. And because the plants stay short and bushy, they're a natural fit for SOG setups where you want uniform canopy height without spending weeks on training.
The honest limitation? MK-Ultra isn't a heavy yielder compared to some modern hybrids. You're growing for quality and potency here, not for weight. The buds are dense and absolutely caked in resin, but don't expect the kind of monster colas you'd get from a stretchy sativa-dominant hybrid. If maximum yield per plant is your priority, something like a Critical Mass might be a better fit. But if you want award-winning genetics in a manageable package that finishes fast — this is the one.
Growing MK-Ultra Feminised Seeds — What to Expect
MK-Ultra feminised seeds produce compact, indica-dominant plants that stay between 100–120cm indoors. That tight structure makes them one of the best strains for SOG setups, where you pack 18–20 plants per square metre and let each one produce a single, dense main cola. No topping, no extensive training — just let them do their thing.
The flowering period of 56–63 days is genuinely quick. We've seen growers push it to day 63 for maximum resin development, and the extra few days are worth it — the trichomes go from clear to milky in that final week, and the pine aroma intensifies noticeably. Speaking of aroma: expect your carbon filter to earn its keep. MK-Ultra has a sharp, fresh pine scent that's pleasant but not subtle. By week 5 of flower, the whole tent smells like a conifer forest after rain.
The buds themselves are distinctive — small, round, incredibly dense, and covered in a visible layer of resin. They look like frosted golf balls. Trimming is straightforward because the leaf-to-bud ratio is low, and the tight bud structure means you won't spend hours picking out sugar leaves.
| Specification | Detail |
|---|---|
| Seed Bank | T.H. Seeds |
| Seed Type | Feminised |
| Genetics | G-13 x OG Kush |
| Dominance | Indica |
| Flowering Time | 56–63 days |
| Plant Height | 100–120cm |
| Best Setup | SOG (18–20 plants/m²) |
| Flavour Profile | Fresh pine |
| Awards | 1st place High Times Cannabis Cup 2003, 2nd place 2004 |
| Pack Sizes | 3 or 5 seeds |
MK-Ultra Feminised Seeds — Flavour, Aroma, and Effect
The flavour profile of MK-Ultra is dominated by fresh pine — clean, sharp, and resinous. It's not a complex terpene cocktail; it's a direct, no-nonsense pine hit that coats the palate. If you've ever cracked open a jar of properly cured OG Kush and caught that first wave of forest-floor aromatics, MK-Ultra sits in the same family but with more sharpness from the G-13 side. The smoke is smooth for an indica, and the pine lingers on the exhale.
The effect is immediate and stimulating — not the slow creep you get from some indica strains. It hits fast, which is consistent with the OG Kush lineage. T.H. Seeds named it after the CIA's Cold War mind-control programme, and while that's obviously marketing flair, the rapid onset does catch you off guard if you're expecting a slow indica build.
Indoor vs. Outdoor — Where MK-Ultra Feminised Seeds Perform Best
MK-Ultra feminised seeds are built for indoor growing. The compact 100–120cm height, tight internodal spacing, and fast 56–63 day flowering time all point to a strain that was bred with tents and grow rooms in mind. SOG is the optimal setup — pack them in at 18–20 plants per square metre, keep the canopy flat, and let each plant focus its energy on one dense main cola.
Can you grow MK-Ultra outdoors? Yes, in a warm, dry climate with consistent sun. But you lose the advantages that make this strain special. Indoors, you control the environment, and MK-Ultra rewards that control with uniform growth and predictable results. Outdoors, the compact structure means lower yields compared to strains that stretch and branch naturally. If you're growing outdoors and want an indica, there are better-suited options. If you're growing indoors with limited vertical space — MK-Ultra is one of the best choices in the T.H. Seeds catalogue.
Common Problems Growing MK-Ultra — And How to Avoid Them
- Humidity in late flower. Those dense, golf-ball buds are beautiful but they trap moisture. Keep relative humidity below 50% in the final two weeks of flowering. If you're running a SOG with 18–20 plants per square metre, airflow between plants is critical — a small oscillating fan at canopy level makes a real difference.
- Overfeeding. MK-Ultra is a compact plant with a moderate appetite. It doesn't need heavy feeding schedules. We'd start at 75% of your nutrient manufacturer's recommended dose and only increase if the plant asks for it. Nitrogen toxicity shows up as dark, clawed leaves — easy to spot, easy to fix if you catch it early.
- Expecting massive yields. This isn't a production strain. The buds are dense and resinous, but each plant produces moderate weight. The quality-to-quantity ratio is where MK-Ultra wins. If you go in expecting Critical Mass numbers, you'll be disappointed. If you go in expecting award-winning resin production on a compact, fast-finishing plant — you'll be very happy.
- Stretching during the flip. MK-Ultra doesn't stretch much, but the first 10 days after switching to 12/12 will see some vertical growth. Account for an extra 10–15cm above your final veg height. In a SOG setup, this is rarely an issue — the plants are already short when you flip.
- Impatience at harvest. The 56-day mark is the minimum. Pushing to 63 days gives the trichomes time to mature fully, and the pine flavour develops more depth in that final week. Check trichomes with a loupe — you want mostly milky with a few amber.
Running MK-Ultra in a SOG setup? You'll want a proper grow tent to control the environment — the Secret Jardin Dark Room range fits 18–20 plants per square metre and the 600D fabric blocks light properly. Pair it with a carbon filter to handle the pine aroma, which gets intense from week 5 of flower onwards.
MK-Ultra vs. Other Indica Feminised Seeds
If you're comparing MK-Ultra feminised seeds against other indica options, here's how it stacks up against two popular alternatives we carry:
| Strain | Genetics | Flowering Time | Height | Best For |
|---|---|---|---|---|
| MK-Ultra (T.H. Seeds) | G-13 x OG Kush | 56–63 days | 100–120cm | SOG setups, resin production, compact spaces |
| Northern Lights | Afghani indica landrace | 55–65 days | 100–130cm | Beginners, stealth grows, low odour |
| Critical Mass | Afghani x Skunk #1 | 55–60 days | 100–140cm | Maximum yield, commercial grows |
Northern Lights is the classic beginner indica — forgiving, low odour, reliable. MK-Ultra is a step up in resin production and flavour complexity, but it's less forgiving with humidity in late flower. Critical Mass gives you more weight per plant but doesn't match MK-Ultra's trichome coverage or the pine flavour profile. We'd pick MK-Ultra over both if resin quality and compact growth are your priorities. If you just want the heaviest harvest possible, go Critical Mass.
Frequently Asked Questions
How long do MK-Ultra feminised seeds take to flower?
56–63 days from the switch to 12/12 lighting. Most growers see the best results at the 60–63 day mark, when trichomes have fully matured to a milky-white colour with some amber. Harvesting at day 56 is possible but you'll sacrifice some resin development.
What's the best grow setup for MK-Ultra feminised seeds?
Sea of Green (SOG) at 18–20 plants per square metre. The compact 100–120cm height and tight internodal spacing make MK-Ultra one of the best SOG strains available. Each plant produces a single dense main cola without the need for topping or training.
How tall does MK-Ultra grow indoors?
100–120cm in most indoor setups. Expect an extra 10–15cm of stretch in the first 10 days after flipping to 12/12. It's one of the shortest indica strains we carry — fits comfortably in tents with 150cm or more of vertical space.
What does MK-Ultra smell and taste like?
Fresh pine — sharp, clean, and resinous. The aroma intensifies significantly from week 5 of flowering. The taste follows the nose: a direct pine hit on the inhale with a smooth, lingering finish. A carbon filter is strongly recommended from mid-flower onwards.
Is MK-Ultra difficult to grow?
Moderate difficulty. The plant itself is compact and manageable, but the dense buds are susceptible to mould if humidity isn't kept below 50% in late flower. Feed conservatively — start at 75% of recommended nutrient levels. Not the most forgiving strain for absolute beginners, but very manageable if you monitor your environment.
Should I buy the 3-pack or 5-pack of MK-Ultra feminised seeds?
Go with the 5-pack if you're running a SOG setup — you'll need 18–20 plants per square metre, so a single 5-pack is just the starting point. The 3-pack works for test runs in a small tent or if you want to evaluate the genetics before committing to a full canopy.
Did MK-Ultra really win the Cannabis Cup?
Yes — twice. MK-Ultra took 1st place at the 2003 High Times Cannabis Cup and came back for 2nd place in 2004. Both wins were in the indica category. T.H. Seeds bred the strain specifically by crossing G-13 with OG Kush, and the Cup results put it on the map.
Last updated: April 2026
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Medical disclaimer. This content is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare provider before use of any substance.