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Northern Lights Shop

Growing

Growing Northern Lights: flowering time, yield and breeder specs

Seed versions of Northern Lights flower in about 45–60 days indoors by most breeders’ figures, and outdoor harvests run from late September to mid-October. Breeders rate it easy to moderate, with compact plants and heavy yields.1,2,3,4

Breeder specs side by side

Source and versionFloweringIndoor yieldOutdoorDifficulty
Sensi Seeds, regular45–50 daysAbout 500 g/m²Up to 1.5 kg per plant reported; 150–200 cm (80–130 cm indoors)1Relatively easy; experience helps for big harvests1
Sensi Seeds, feminized45–50 daysAbout 500 g/m²About 600 g per plant; 150–200 cm5Easy5
Sensi Seeds, automaticAbout 60 days; 11–13-week life cycleAbout 400 g/m²50–80 g per plant; taller than its 80–130 cm average6Very easy, even in colder climates6
Royal Queen Seeds, Northern Light (feminized S1)55–60 days18–19 oz/m²Late September; 20–22 oz per plant; 6–7 ft2—
Royal Queen Seeds, Northern Light Auto45–55 days; 70–85 days from germination18–19 oz/m²6–8 oz per plant; 4–5 ft7—
Crop King Seeds, feminized8–10 weeks400 g/m²Late September to mid-October; 550 g per plant; 5–8 ft3Moderate3
Leafly (database)7–9 weeks; 45–50 days in its description400–500 g/m²—Easy4

Seed sellers’ figures are their own claims. Weedmaps notes that some versions list about 45–50 days of flowering while others take longer, and that breeder lines vary considerably.8

What the plant is like

Expect a compact, bushy, multi-branched plant that stays short indoors and supports dense, resin-coated buds; Sensi Seeds puts indoor height at about 80–130 cm.1,5 SeedFinder describes broad, dark-green leaves and pine-shaped flowers with yellow and orange pistils, and growers quoted by Leafly report purple, crystal-coated buds.4,9

Leafly’s grow notes say a high calyx-to-leaf ratio makes trimming easy and that the plant grows best multi-branched with moderate to heavy feeding.4 Sensi Seeds recommends sea-of-green or screen-of-green training for its feminized version.5

What to watch for

Warmth and humidity. Sensi Seeds says outdoor plants need long, hot summers, with the Mediterranean as the ideal climate.1 On mold, accounts differ: Alchimia warns that the compact buds can develop mold in flower, especially in humid climates, and Weedmaps says the dense flowers make airflow and moisture worth watching near harvest, while Royal Queen Seeds’ blog says the buds are not dense enough for mold to be a problem.8,10,11

Odor is modest by Sensi Seeds’ account: it says its feminized version does not produce much odor while growing.5 And the name covers different genetics: Royal Queen Seeds’ version is an S1 rated 100% indica, while Sensi Seeds’ seeds are 90% indica.1,2

Seeds and the law in the US

Under the amended federal definition of hemp, viable seeds from cannabis plants above 0.3% total THC, including THCA, are not hemp.12 Congress delayed that exclusion, with most of the new definition, from Nov 12 to Dec 11, 2026; only the exclusion of products with cannabinoids the plant cannot produce naturally starts on Nov 12.13 Home cultivation rules are set by each state. This site does not sell seeds.

Sources

  1. Sensi Seeds, Northern Lights regular seeds. Accessed Oct 3, 2026.
  2. Royal Queen Seeds, Northern Light feminized seeds. Accessed Oct 3, 2026.
  3. Crop King Seeds, Northern Lights feminized marijuana seeds. Accessed Oct 3, 2026.
  4. Leafly, Northern Lights strain information. Accessed Oct 3, 2026.
  5. Sensi Seeds, Northern Lights feminized seeds. Accessed Oct 3, 2026.
  6. Sensi Seeds, Northern Lights Automatic seeds. Accessed Oct 3, 2026.
  7. Royal Queen Seeds, Northern Light Auto seeds. Accessed Oct 3, 2026.
  8. Weedmaps, Northern Lights strain page. Accessed Oct 3, 2026.
  9. SeedFinder, Northern Lights (Sensi Seeds). Accessed Oct 3, 2026.
  10. Alchimia, The origins of Northern Lights (2015-08-17). Accessed Oct 3, 2026.
  11. Royal Queen Seeds (Luke Sumpter), Northern Lights: a cannabis classic and true indica legend (2020-03-20). Accessed Oct 3, 2026.
  12. Congressional Research Service, Changes to the statutory definition of hemp and implications for agricultural policy (IF13136) (2026-09-28). Accessed Oct 3, 2026.
  13. U.S. Government Publishing Office, Continuing Appropriations and Extensions Act, 2027 (P.L. 119-103), sec. 2019. Accessed Oct 3, 2026.