Critical Extrem Auto by Seeds66

Critical Extrem Auto strain photo
Type ruderalis/indica/sativa · autoFlower ±56 daysCross Critical Extrem × Ruderalis

Critical Extrem Auto, from breeder Seeds66, is an autoflowering strain descended from Critical Extrem × Ruderalis. Indoors it typically finishes flowering in around 56 days from sprout. The environment targets below are the same stage-by-stage bands the Cultivar journal grades real Critical Extrem Auto grows against.

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BreederSeeds66
Typeruderalis/indica/sativa
Flowering time±56 days
EnvironmentOutdoors, Greenhouse
LineageCritical Extrem × Ruderalis

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Autoflower note: runs on age, not light schedule — see the week-by-week autoflower schedule.

🧬 Explore the family: Critical Extrem · Ruderalis

Ancestry Pedigree

Critical Extrem
Seeds66
Critical Plus
Dinafem
Critical Bilbo
Clone Only Strains
Critical Mass
Mr Nice Seedbank
Afghanistan Indica
Original Strains
Skunk Nr1
The Seed Bank
Skunk Nr1
Cultivators Choice
Afghanistan Indica
Original Strains
Mexico Sativa
Original Strains
Colombia Sativa
Original Strains
Ruderalis
Original Strains

Growing Critical Extrem Auto: what to expect

Because Critical Extrem Auto is an autoflower it runs on age, not photoperiod: keep it under 18–20 hours of light from sprout to harvest, start in its final pot, and go easy on training after week 3 — autos never pause to recover. Growers familiar with Critical Extrem or Ruderalis will recognize much of its behavior. Whatever the listing says, the cut in YOUR tent is the ground truth: log feedings, readings, and photos, and let the trends — not the label — drive decisions.

Critical Extrem Auto FAQ

How long does Critical Extrem Auto take to flower?

Critical Extrem Auto typically flowers in around 56 days from sprout (autoflower — no light-schedule flip needed). Individual phenotypes vary, so judge harvest readiness by trichome color, not the calendar.

Is Critical Extrem Auto an indica or a sativa?

Critical Extrem Auto is listed as ruderalis/indica/sativa (autoflowering).

What are the parents of Critical Extrem Auto?

Critical Extrem Auto was bred from Critical Extrem × Ruderalis by Seeds66.

What environment does Critical Extrem Auto like?

Standard cannabis bands work well: VPD 0.8–1.1 kPa in veg and 1.0–1.4 kPa in flower, with humidity stepping down from 65–75% as a seedling to 40–50% in late flower. See the stage-by-stage table on this page.

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Published by Cultivar (logmygrow.com), a structured grow journal. These reference bands are the same ones the app grades real grows against. Free to cite with a link. Some outbound product links are affiliate links — see disclosures.