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How to Grow Northern Lights Seeds (2025 Grow Diary)

September 18, 2025 / in Cannabis Health / Mesmerise

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Northern Lights is a classic, largely indica strain (95% indica / 5% sativa) with roots in Afghani × Thai landrace genetics. At up to 18% THC and ~1% CBD, it delivers deep euphoria, relaxation, and a therapeutic body high. Flavor is earthy, piney and spicy. Plants stay moderately sized (50–60 in), finish flowering in 7-8 weeks, and yield around 1.5-1.6 oz/ft² indoors or 18-22 oz/plant outdoors. Harvest is typically in the first half of September.

Here’s your step-by-step guide on how to grow Northern Lights strain from seed to cure.

👉 Shop Northern Lights seeds at Hypno Seeds
🔗 Learn more about Northern Lights strain on Leafly

Setup Checklist for Growing Northern Lights Seeds

Northern Lights is resilient, compact, and forgiving—but it rewards stable conditions, especially in flower.

🏕️ Indoor Setup

Tent: 2×2 ft or larger
Lighting: Full spectrum LED, 400-600 W eq.
Ventilation: Inline fan + carbon filter
Airflow: Oscillating fan for canopy circulation
Humidity Control: Hygrometer + humidifier/dehumidifier
Pots: 3-5 gallon fabric or equivalent
Medium: Rich soil or coco + perlite mix
Nutrients: Good veg & bloom feeds, plus Cal-Mag support
Water: Maintain pH ~6.2-6.6

🌞 Outdoor Notes

Climate: Warm, sunny with cool nights
Soil: Well-draining, fertile
Harvest: Early September before fall rains
Protection: Low risk of pests, but support colas if heavy

Germination: Starting Your Northern Lights Grow

Use the paper towel method:

Place seeds between two damp towels, keep warm (~70-75°F), check daily.
Once taproot ~½”, plant root-tip down in your chosen medium.

⚠️ Avoid direct light or high heat/scorch on fragile sprouts.

Week 1: Seedling Stage

Northern Lights seedlings are compact and hardy, but they’re still fragile at this stage. Keep lights at a safe distance to avoid stretching, and always prioritize airflow over extra watering. This strain’s indica roots mean the leaves will appear broad early on, a sign that the plant is settling into its growth rhythm.

A visual showing the cannabis seedling stage, from sprouted seed to first set of true leaves.

Tiny plants develop cotyledons and first true leaves.
Keep humidity ~65-70%, temp ~72-77°F.
Light soft, 18-24h, low intensity.
No nutrients yet (or very light Cal-Mag if using inert media).

Week 2: Early Veg + Optional LST

As growth picks up, Northern Lights responds well to gentle handling. Its strong indica genetics keep internodes short, so canopy management is easier compared to stretchy sativas. If humidity dips too low, consider using a humidity dome for young plants.

Rapid growth of fan leaves, strong internode thickening.
Light schedule still ~18 hrs; increase intensity.
Use light veg nutrients (¼ strength).
Consider Low Stress Training to shape canopy.

Week 3: Veg Expansion

By now, fan leaves widen and begin shading the soil surface. This helps maintain root zone moisture naturally. If growing in coco, watch for early magnesium deficiencies—Northern Lights is slightly hungry for Cal-Mag under artificial lights.

What to Expect

Height: 6–10 in
Growth: Rapid leaf production, canopy fills in
Structure: Short internodes, classic indica shape

Environment Targets

Light: 18/6 (~400 PPFD)
Humidity: 55–60%
Temp: 73–78°F
Nutrients: Veg feed at ½ strength

Week 4: Pre-Flower & Final Veg Training

This week is crucial for shaping the plant. Its dense canopy may require leaf tucking or selective defoliation to prevent moisture pockets that could later invite mold. Outdoors, Northern Lights will adapt well to temperature shifts, showing its landrace resilience.

Bushy plant, prepping for flowering.
Full veg strength nutrients; boost light as possible.
Prune lower leaves for airflow.
Final training: LST or SCROG net to spread canopy evenly.

Week 5: Flower Begins

Once flipped to 12/12, Northern Lights won’t stretch as much as sativa hybrids—usually doubling at most. This makes it easy to manage indoors. Pistils often appear in clusters early, a preview of the dense colas to come.

Switch to 12/12 light cycle.
Buds start forming, pistils visible.
Lower humidity to ~45-50%, keep temps ~72-78°F.
Begin bloom nutrients (more P & K, reduce N).

Week 6: Bud Sites & Trichome Development

The first trichomes begin to glisten under light, proof of the plant’s resinous Afghani heritage. Leaves may start to smell strongly of pine and spice when rubbed. Keep humidity stable here; dense indica buds mean airflow is everything.

A labeled diagram of a basic indoor cannabis grow tent setup with full-spectrum LED light, inline fan + carbon filter, clip-on fan, fabric pots, and hygrometer.

Bud sites get more pronounced; trichomes begin.
Aroma develops earthy, piney spice.
Ensure solid airflow around dense bud growth.
Maintain ~600 PPFD light, humidity ~45%.

Week 7: Bud Fattening & Aroma Surge

Buds thicken rapidly now, and the aroma shifts toward earthy pine with spicy undertones. Nutrient uptake increases, so ensure a consistent watering routine. If grown outdoors, keep an eye on September rains—these dense buds don’t like excess moisture.

Buds swell; resin production heightens.
Spicy, pine, and woody aroma intensifies.
Temps slightly cooler at night; humidity ~40-45%.
Use terpene boosters if available.

Week 8: Final Flush & Ripeness Check

Trichomes cloud over quickly, often showing amber earlier than expected. Northern Lights is forgiving, so even if you miss the perfect harvest window by a few days, you’ll still get great potency. A proper flush at this stage makes all the difference in flavor, smoothing out the earthy-spice profile.

Most pistils darkened; trichomes mostly cloudy with some amber.
Flush with plain pH’d water 5-7 days before harvest.
Humidity lowered to ~35-40% to avoid mold; temp ~65-70°F.

Harvest & Curing

Outdoor or indoor: harvest in first half of September.
Dry at ~60°F / 55% RH in darkness for 10-14 days.
Cure in jars, burping daily first week, then regularly.
Expect relaxing, euphoric, piney and spicy buds as the final profile.

Final Thoughts on Growing Northern Lights Seeds

Northern Lights remains a benchmark indica for a reason. It’s easy to grow, fast to finish, and offers a deeply satisfying, relaxing high. Perfect for beginners and veterans alike.

If you’ve been searching for how to grow Northern Lights strain, this diary lays out everything from germination to the final cure.

👉 Shop Northern Lights seeds at Hypno Seeds
👉 Browse more Indica Seeds
🔗 Learn more about Northern Lights strain on Leafly

FAQ: Growing Northern Lights Seeds

How long does Northern Lights take to flower?
7-8 weeks indoors; ready outdoors in early September.

How tall does Northern Lights grow?
About 50-60 inches under good conditions.

Is Northern Lights easy to grow?
Yes, very forgiving and resilient for beginners.

What yields can I expect?
Indoors: ~1.5-1.6 oz/ft². Outdoors: ~18-22 oz/plant.

What does Northern Lights taste like?
Earthy, piney, with spicy undertones.

What effects does Northern Lights have?
Deep relaxation, happy euphoria, very therapeutic, great for evening or stress relief.