Auto MK-Ultra Kush by TH Seeds – Heaviest Indica Autoflower | 9-Week Flowering, 350–450 g/m² Yield

Auto MK-Ultra Kush by TH Seeds is the heaviest indica-dominant autoflower you can grow in just 9 weeks, delivering up to 450 g/m² of potent, resin-rich bud with minimal effort.

Feeling like your current setup is all chaos and no chill? Are your plants stretching, stalling, or just not packing the punch they should? You’re not alone — many growers waste cycles on underperforming autos that look good but deliver weak highs and mediocre yields.

That stress? That disappointment when harvest time comes and you’re left with airy buds and a headache? It steals your confidence and makes you question whether growing is even worth it. You’ve invested time, money, and space — you deserve a strain that actually delivers.

Meet Auto MK-Ultra Kush: the no-nonsense, high-yield autoflower bred from OG Kush and G13, perfected by TH Seeds. It grows compact (1.00–1.25 m / 3.28–4.10 ft), finishes fast (9 weeks), and produces dense, trichome-blitzed flowers that reek of earthy citrus and pungent sweetness. Whether you're in a stealthy indoor tent or a sunny backyard, this strain locks in quality without demanding perfection.

How Your Grow Space Transforms with Auto MK-Ultra Kush

You’ll go from cluttered and uncertain to confident and in control. This strain doesn’t need constant babysitting — it thrives on simplicity. Its compact size means you can fit more plants in less space, and its rapid cycle frees up room for the next round. No more guessing games or endless tweaking.

With tight internodal spacing and a bushy structure, Auto MK-Ultra Kush fills out evenly under light, maximizing canopy efficiency. You’ll see fewer weak stems and wasted energy — just solid, upward growth leading to heavy colas. The result? A clean, organized grow that looks pro-level, even if it’s your first time.

What You’ll Harvest from This Indica Powerhouse

• Up to 450 grams per square meter (1.1 oz/ft²) indoors under optimal conditions
• 100–150 grams per plant (3.5–5.3 oz) outdoors in sunny climates
• Dense, frosty buds with a thick coat of amber-tipped trichomes
• Rich aroma of earth, diesel, and sweet citrus — a true Kush legacy
• Smooth smoke with a spicy-sweet finish that lingers on the palate
• Deep physical relaxation perfect for evening or nighttime use
• Consistent performance across soil and coco setups

Steps to a Successful Auto MK-Ultra Kush Grow

1. Start with a final pot of 18–27 L (5–7 gal) to avoid transplant stress
2. Use well-aerated soil or coco with perlite for optimal root development
3. Provide 18–20 hours of light daily — no light cycle changes needed
4. Keep humidity at 50–60% in veg, dropping to 40–50% in flowering
5. Feed moderately — this strain doesn’t need heavy nutrients to shine
6. Apply low-stress training (LST) early to open up the canopy
7. Harvest when 70% of trichomes turn amber for maximum sedation

Advantages of Growing This Fast-Flowering Indica

• 9-week flowering time from seed to harvest — perfect for quick turnover
• Compact height ideal for discreet or space-limited grows
• High resistance to mold and pests — great for humid climates
• Minimal pruning needed — avoid topping or FIM to prevent stress
• Consistent yields even for beginner growers
• Powerful, long-lasting body high for deep relaxation
• Exceptional resin production — ideal for extracts

Technical specifications

• Breeder / Brand: TH Seeds
• Type: Autoflowering
• Dominance: Mostly Indica
• Genetics / Cross: OG Kush × G13 × Ruderalis
• Flowering time: 9 weeks (from seed to harvest)
• Indoor yield: 350–450 g/m² (12.3–15.9 oz/ft²)
• Outdoor yield: 100–150 g/plant (3.5–5.3 oz/plant)
• Indoor height: 100–125 cm (39.37–49.21 in)
• Outdoor height: 100–125 cm (39.37–49.21 in)
• Difficulty: Low
• Structure and vigour: Compact, bushy, moderate stretch
• Ideal climate: Temperate, Mediterranean, continental
• Resistance: High resistance to fungi and pests
• Training: Suitable for LST, not for aggressive pruning
• Recommended pot: 18–27 L final pot early
• Light: 18–20 h daily throughout the cycle
• Temperature: 22–26 °C (veg), 20–25 °C (flowering)
• Humidity: 60–70% (seedling), 50–60% (veg), 40–50% (flowering)
• pH: 6.0–6.5 (soil), 5.8–6.2 (coco/hydro)
• Smell in grow: High — use a carbon filter if needed
• THC: 18–22%
• CBD: 0.1–0.3%
• Aromatic profile: Myrcene, caryophyllene, limonene
• Flavour: Earthy, pungent, sweet citrus, diesel
• Effect: Relaxing, sleepy, euphoric — best for nighttime

How to Grow Auto MK-Ultra Kush for Best Results

Get the most out of this heavy-yielding autoflower with a simple, science-backed approach.

Quick overview: TH Seeds’ Auto MK-Ultra Kush is a low-difficulty, 9-week autoflower ideal for indoor tents or outdoor patios in temperate climates.

Safe start: Germinate in a moist, dark environment at 22–25 °C.

• Use a humidity dome for consistent moisture
• Transplant once the taproot is ~1 cm long
• Start in final pot to avoid root stress
• For a faster start, Seedbox Plagron boosts root strength

Stable seedling: Keep humidity high and light moderate.

• Maintain RH at 60–70% for first week
• Use soft LED or CFL lighting (250–400 lux)
• Water lightly — let topsoil dry between waterings
• Incorporate Root Juice BioBizz to enhance early root mass

Directed growth: Focus on structure and airflow.

• Apply LST when 4–5 nodes form to spread canopy
• Use 18–20 h light cycle with full-spectrum LEDs
• Switch to flowering nutrients after week 3
• SensiZym Advanced Nutrients improves nutrient uptake

Efficient flowering: Maximize resin and density.

• Lower humidity to 40–50% to prevent mold
• Boost PK in weeks 5–7 for heavier buds
• Avoid topping — autos can’t recover from stress
• Ensure strong airflow to support dense colas

Harvest and refinement: Time it right for maximum effect.

• Harvest when 60–70% trichomes are amber
• Flush 7–10 days before harvest with plain water
• Dry at 18–22 °C and 50–60% RH for 7–10 days
• Cure in jars for 2–4 weeks to enhance flavor

Frequently Asked Questions

How much yield can I expect from Auto MK-Ultra Kush?

Indoors, expect 350–450 g/m² under LED or HPS lighting. Outdoors, each plant can produce 100–150 grams in a sunny location with good care.

Does this strain need a lot of nutrients?

No — Auto MK-Ultra Kush performs best with moderate feeding. Over-fertilizing can lead to nutrient burn and reduce resin production.

Can I grow this in a small tent?

Absolutely. At 100–125 cm tall, it fits perfectly in a 120x120x200 cm grow tent. Use LST to control shape and maximize light exposure.

Is the smell strong during flowering?

Yes, it has a pungent, earthy-diesel aroma. Use a carbon filter like those in Seedfinder products to control odor.

When should I harvest for a sleepy effect?

For maximum relaxation, wait until 70% of trichomes turn amber. Earlier harvests (mostly milky) will be more uplifting.

Personal Experience of Pevgrow’s CEO (Alan)

I grew Auto MK-Ultra Kush in my 1.20 m x 1.20 m tent with a 600W LED. Planted directly in 20L pots with Plagron Royal Mix, I used Root Juice from week one and SensiZym throughout. By week 5, the smell was intense — I had to fire up my carbon filter. The buds packed on weight fast, and by week 9, they were rock-hard and glistening.

What surprised me was how forgiving it was. I overwatered once, and it bounced back in two days. The high is a total brain-melter — perfect for crashing after a long day. My tip? Don’t train it too hard. Let it do its thing, feed it lightly, and you’ll be rewarded with one of the most potent, hassle-free autos I’ve ever grown.