Critical Extrem Auto by Seeds66 is the result of two years of refinement of our feminized Critical Extrem. The goal was an autoflower that behaves like a shortened photoperiod: high yields, dense buds and intense aroma – all wrapped into roughly 70–80 days from seed to harvest. That is exactly what this line delivers: vigorous plants, a strong flower-to-leaf ratio and buds that feel more like compact photoperiod flowers than typical autos.
Quick Info: Critical Extrem Auto
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Genetics: Critical Extrem x Seeds66 Ruderalis
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Type: feminized, autoflowering indica-dominant line
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Cycle (indoor): 70 – 80 days from seed to harvest
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Indoor yield: 400 – 500 g/m²
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Outdoor yield: 60 – 100 g per plant
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THC content: 18 – 22 %
Origin & Seeds66 Selection
Critical Extrem Auto is built on our feminized Critical Extrem, combined with a stable Seeds66 Ruderalis line. The idea was to transfer the character of the photoperiod version – yield, density and aroma – into a fully automatic format without losing its profile. Over several generations we selected plants that showed clear autoflowering behavior and stayed close to the original Critical Extrem expression.
During our internal test runs in California we focused on three main points: consistent development under 18/6 or 20/4 light, a strong flower-to-leaf ratio and compact buds with a sweet, lemony and earthy bouquet. Only lines that delivered this combination in a repeatable way made it into the final Critical Extrem Auto selection.
Growth & Cultivation
For an autoflower, Critical Extrem Auto grows vigorously and with a clear main structure. Indoors it typically reaches 60–110 cm, depending on pot size, light intensity and the way you start the seedlings. Internodes are clearly spaced, side branches develop quickly and carry dense buds that gain noticeable weight in the last weeks.
Outdoors the strain can reach 100–180 cm. A well-draining substrate, plenty of light and enough root space are crucial. With an early start and healthy soil, multiple runs per season are possible. Because the buds get very compact, occasional thinning of lower growth and maintaining good airflow around the plants pays off in quality.
The full life cycle takes about 70–80 days from seed to harvest, indoors as well as outdoors. The smell becomes intense toward mid to late flower, so a reliable carbon filter is strongly recommended for indoor grows.
Seeds66 Tip: For Critical Extrem Auto, start directly in the final pot – around 11–18 liters indoors – and avoid repotting and heavy topping. Gentle LST and stable light schedules help the plants use their short vegetative window efficiently and push yields towards the 400–500 g/m² range.
Aroma & Terpenes
The aroma of Critical Extrem Auto closely mirrors the feminized mother line, often with an even more present edge in small spaces. Opening the jar brings forward sweet lemon notes, backed by a warm earthy base. When you break up the buds, resinous and herbal tones join in and round off the profile.
On the palate, you can expect a mix of sweet citrus and earth with a lingering resin hint. Growers who like the classic Critical scent will find this version hard to ignore – proper odor control is important in active flowering rooms.
Effects
With 18–22 % THC, Critical Extrem Auto delivers a solid, clearly noticeable high. Most users report a pleasant lift in mood and an inner calm, followed by a relaxing body component that eases tension and helps to unwind.
It fits well at the end of a busy day or in the evening when you want to slow down. At moderate doses there is still enough clarity for conversations and light activities; higher doses tend to move the experience into a heavier, couch-oriented body stone.
Seeds66 Approach
For us, an autoflower should never feel like a compromise. Critical Extrem Auto earns its place because it combines a defined time frame with convincing performance: predictable runs, strong yields and a profile that clearly relates to the feminized original.
Our principle here: We keep autoflowers only if they feel like a full-value option, not a fallback.
Characteristics of Critical Extrem Auto
Type indica-dominant autoflower
Category feminized, autoflowering Seeds66 line
Genetics Critical Extrem – Seeds66 Ruderalis
Effect relaxing, mood-lifting, ideal for winding down
Flavor sweet / lemon / earthy with resin notes
Cycle indoor 70 – 80 days from seed to harvest
Harvest outdoor 70 – 80 days from seed to harvest
Yield indoor 400 – 500 g/m²
Yield outdoor 60 – 100 g per plant
Height indoor 60 – 110 cm
Height outdoor 100 – 180 cm
THC / CBD 18 – 22 % / 0.3 %
Climate zones temperate climates, balcony/garden or greenhouse with good airflow
Seeds66 Note strong auto line for growers who want photoperiod-like output in a compact time frame.
Note: This text describes the autoflowering version of Critical Extrem. If you prefer the classic photoperiod behavior, you can find our feminized line here:
Critical Extrem feminized.
Frequently Asked Questions about Critical Extrem Auto
1. Is Critical Extrem Auto suitable for beginners?
Yes. As long as light, substrate and watering are reasonably on point, it runs very reliably. The main thing is to avoid heavy stress in the early growth phase.
2. How long does a full run take?
Usually 70–80 days from seed to harvest, indoors and outdoors. Individual plants may finish a few days earlier or later.
3. What light schedule should I use indoors?
Typical autoflower schedules such as 18/6 work very well; some growers also use 20/4. Consistency is more important than frequent changes.
4. How can I improve yields?
Start directly in the final pot, offer enough root space, avoid hard pruning and use balanced nutrition. Hydroponic setups or very airy substrates can push the output even further.
5. Does Critical Extrem Auto smell strong during flowering?
Yes. The sweet lemon and earthy notes become very intense, especially in late flower. A good carbon filter is strongly recommended for indoor grows.
6. How does the auto differ from the feminized version?
Critical Extrem Auto offers a similar aroma and effect profile to the photoperiod version but finishes in a fixed 70–80 day window. The feminized version Critical Extrem feminized allows more control over vegetative time and plant size.
Seeds66 Editorial Team
All descriptions are based on our tests and documentation in California. We only publish strains we have documented ourselves. Focus: germination strength, stability and reproducible results for the German-speaking market.
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