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If you have been looking for the most reliable northern lights autoflower grow guide, you are in the right place. Northern Lights is one of those strains that has stood the test of time — decade after decade, growers keep coming back to it for its consistency, its resilience, and the quality of what ends up in the jar at harvest time. Add ruderalis genetics and you get an autoflowering version that is faster, more forgiving, and genuinely accessible to growers at every level.
In this complete guide, we cover genetics, effects, a full week-by-week grow breakdown, the top 5 products we recommend, a multi-currency price comparison, and honest answers to the questions growers ask most often about
What Is Northern Lights Autoflower?
Northern Lights has been a cornerstone of cannabis culture since the 1980s. Originally bred in North America, it became one of the most decorated strains in competitive cannabis history. The northern lights autoflower crosses that legendary genetics with ruderalis, producing a plant that flowers automatically around day 21 to 28 from germination — no light schedule changes required.
This makes the entire growing process significantly more straightforward. If you want to understand how autoflowers fit into a broader feeding strategy, our outdoor autoflower feeding schedule guide covers nutritional planning in detail.
Effects and Experience
Northern Lights Autoflower delivers a deeply physical, body-focused effect — heavy, warm, and genuinely relaxing. THC ranges from 14 to 18 percent. Effects onset within 15 to 20 minutes and persist for 2 to 4 hours. Many users report benefits for insomnia, chronic pain, muscle tension, and anxiety.
Strain Profile
Genetics: Northern Lights x Ruderalis | Type: Indica-dominant autoflower | THC: 14–18% | CBD: Under 1% | Flowering: 8–9 weeks | Indoor yield: Up to 400g/m2 | Height: 60–100cm | Aroma: Sweet, earthy, pine
How to Grow Northern Lights Autoflower
Lighting
Run 18/6 throughout the entire life cycle. Full-spectrum LEDs from Mars Hydro and Spider Farmer deliver the spectrum range autoflowers respond to across both vegetative and flowering stages. Our autoflower training guide explains how canopy management interacts with your lighting setup.
Environment
Target 20 to 26 degrees Celsius during the light period. Humidity at 60 to 65 percent during vegetation, dropping to 40 to 50 percent during flower to prevent botrytis on those dense indica colas.
Feeding
Start at half the recommended dose during vegetation and scale gradually. Growing in coco coir? Add cal-mag from week 2. Our indoor cannabis strains guide includes feeding comparisons across multiple indica-dominant varieties.
Training
LST from week 2 or 3 increases yield by 20 to 30 percent by opening the canopy to more direct light. If topping, do it before day 20. See our dedicated topping autoflower guide for the exact process.
Week-by-Week Grow Guide
Week 1 — Germination
Humidity at 70%, temperature at 23–24°C, light at 18/6. Water sparingly. No nutrients yet.
Week 2 — First True Leaves
Begin feeding at quarter strength. Let the top inch of medium dry between waterings.
Week 3 — Vegetative Growth
Increase to half strength nutrients. Begin LST — bend the main stem gently and tie in place.
Week 4 — Strong Vegetation
Full vegetative strength nutrients. Continue LST to spread branches evenly.
Week 5 — Pre-Flower
First white pistils appear. Switch to bloom nutrients with higher phosphorus and potassium.
Weeks 6–7 — Early to Mid Flower
Buds forming and swelling. Keep humidity below 50%. Increase airflow. No nitrogen-heavy feeds.
Week 8 — Full Flower
Dense, resinous buds. Monitor trichomes with a loupe — milky white means harvest is approaching.
Week 9 — Harvest Window
When 70 to 90% of trichomes are milky to amber, flush with plain water for 5 to 7 days then harvest.
Top 5 Products for Northern Lights Auto
1. Royal Queen Seeds — Northern Lights Auto
Stable genetics, reliable germination, and detailed growing data. The most trusted source for Northern Lights Auto seeds.
2. Seedsman — Northern Lights Auto
Excellent genetics at a more accessible price. Ideal for phenotype hunting or growers watching their budget.
3. Mars Hydro FC-E3000 LED
Samsung LM301B diodes, full-spectrum output, 3×3 to 4×4 foot coverage. Exceptional uniformity for autoflower canopies.
4. Spider Farmer SF-2000 LED
Dimmable full-spectrum LED ideal for 2×4 tents. Gradually increase intensity from seedling through flower.
→ Check Price on Spider Farmer
5. Mars Hydro 2×4 Complete Grow Tent Kit
Tent, LED, fan, filter, and ducting — all matched and ready. The fastest way to get a proper grow room running.
Price Comparison Table — Northern Lights Auto 2026
| Product | USD | CAD | AUD | EUR | GBP |
|---|---|---|---|---|---|
| RQS Northern Lights Auto (3 seeds) | $45 | $61 | $70 | €42 | £36 |
| Seedsman Northern Lights Auto (3 seeds) | $32 | $44 | $50 | €30 | £26 |
| Mars Hydro FC-E3000 | $199 | $270 | $305 | €185 | £158 |
| Spider Farmer SF-2000 | $219 | $298 | $335 | €199 | £172 |
| Mars Hydro 2×4 Tent Kit | $299 | $406 | $460 | €278 | £237 |
Common Mistakes to Avoid
Overfeeding — start conservative and build up slowly. Overwatering — let medium dry slightly between waterings. Poor humidity in flower — keep below 50% to prevent botrytis. Topping too late — always top before day 20 on autoflowers. For growing in tough conditions, see our guide to autoflowers in cold climates. For troubleshooting, Grow Weed Easy is an excellent external reference.
FAQ — Northern Lights Autoflower
How long does Northern Lights Auto take from seed to harvest?
Between 63 and 70 days from germination under optimised indoor conditions.
Is Northern Lights Auto good for beginners?
Yes — it is one of the most consistently recommended autoflowers for first-time growers because of its resilience and forgiving nature.
What yield can I expect indoors?
80 to 150 grams per plant under a quality LED with basic LST. Optimised setups can exceed 400g/m2.
Can it be grown outdoors?
Yes — up to 150g per plant, ready approximately 9 weeks after germination regardless of season.
Does Northern Lights Auto need training?
Not required, but LST from week 2 or 3 can increase yield by 20 to 30 percent. See our highest yielding strains guide for more on training and yield potential.
Conclusion
Northern Lights Autoflower has earned its reputation across decades of cultivation. Start with genetics from Royal Queen Seeds or Seedsman, light it with a Mars Hydro FC-E3000 or Spider Farmer SF-2000, keep your environment dialled in, and follow the week-by-week guide above. For more resources, explore our best feminized seeds guide and best beginner-friendly seeds guide. Happy growing. 🌿
