Endless Sky by Dr. Greenthumb

Endless Sky strain photo
Type mostly indicaFlower ±44 daysCross Iran Indica × Grenadine

If you hung around the underground Canadian grow forums back in the day, you’ve definitely heard whispers about Endless Sky. Bred by the notoriously secretive Dr. Greenthumb, this indica-heavy hybrid is a cross between Grenadine and a pure Iranian landrace Indica. The Doc has always been known for releasing gear that actually yields and hits hard, and Endless Sky might just be his magnum opus. It’s a 80/20 indica-dominant plant that earned a massive cult following for producing what old-school growers lovingly call a "slack-jaw stone." You hit this stuff, and your brain just floats away.

In the garden, she is an absolute tank. Growers love her because she throws down heavy yields and shows serious resistance to mold—a trait directly inherited from that rugged Iranian landrace mother. Indoors, she finishes insanely fast. Some guys running dialed-in hydro setups report chopping her in as little as 44 to 50 days, though most run her a solid 8 to 9 weeks to let the trichomes fully amber out. Outdoors, you're usually looking at a mid-to-late September harvest. You’ll see some variation in the phenos from seed, with some getting a bit sensitive to heavy nutrient feedings, but they all pack on crazy weight.

But the real reason people keep hunting down these beans is the terpene profile and the high. The nose is a weird, beautiful mix of earthy florals, sweet berries, and a distinct "buttery" vanilla aroma that coats the room when you open a jar. The high is dreamy, spacey, and deeply sedative, making it absolute medicine for insomnia or severe muscle spasms. It’s one of those rare cuts that lives up to the underground hype, knocking you flat on your back every single time.

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Similar strains

Iranian Bubba KushDr. Greenthumb · ±60 daysIranian ChemdawgDr. Greenthumb · ±60 daysIranian OG KushDr. Greenthumb · ±65 days747Dr. Greenthumb · ±63 daysIranian Cindy 99Dr. Greenthumb · ±60 daysIranian Auto FlowerDr. Greenthumb · ±50 daysJamaican DreamEva Seeds · ±44 daysMighty GrapeFreedom of Seeds · ±44 daysChillaBlueHemp · ±43 daysCraigs SkunkUnknown or Legendary · ±45 daysCritical Poison Fast Version00 Seeds · ±43 daysGorilla Fast00 Seeds · ±43 daysAll Dr. Greenthumb →
BreederDr. Greenthumb
Typemostly indica
Flowering time±44 days
EnvironmentOutdoors
LineageIran Indica × Grenadine
DescendantsSky Lotus, Silver Spice, Oregon Green Seed - Mastodon, Dr. Greenthumb - Fire Hydrant, Flook Juice, The Dope, White Sky

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🧬 Explore the family: Iran Indica · Grenadine · Sky Lotus · Silver Spice · Oregon Green Seed - Mastodon · Dr. Greenthumb - Fire Hydrant · Flook Juice · The Dope · White Sky

Ancestry Pedigree

Iran Indica
Original Strains
Grenadine
Dr Greenthumb
Niagara
Dr Greenthumb
Mostly Sativa
Original Strains
G-13
Unknown or Legendary
Indica
Original Strains

Growing Endless Sky: what to expect

As an indica-leaning plant, expect a modest stretch after the flip (roughly 50–100%) and dense bud structure — which makes late-flower humidity discipline the main risk: keep RH in the 40s once buds fatten to stay ahead of mold. Growers familiar with Iran Indica or Grenadine 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.

Endless Sky FAQ

How long does Endless Sky take to flower?

Endless Sky typically flowers in around 44 days after switching to a 12/12 light schedule. Individual phenotypes vary, so judge harvest readiness by trichome color, not the calendar.

Is Endless Sky an indica or a sativa?

Endless Sky is listed as mostly indica.

What are the parents of Endless Sky?

Endless Sky was bred from Iran Indica × Grenadine by Dr. Greenthumb.

What environment does Endless Sky 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.