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How to Grow Jack Herer Seeds (2025 Grow Diary)

September 17, 2025 / in Cannabis Health / Mesmerise

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Jack Herer is a legendary hybrid (≈ 55% Sativa / 45% Indica) bred from Haze × Northern Lights × Shiva Skunk. It offers up to 20% THC with about 1% CBD, delivering a creative, euphoric high with a clear-headed, slightly spicy-pine bite. Plants grow to 50–60 inches, flower in 8-9 weeks, and produce solid yields both indoors and outdoors.

Jack Herer Strain Snapshot

Gender: Feminized
THC: Up to 20%
CBD: Up to ~1%
Flavor: Piney, Spicy
Type: 45% Indica / 55% Sativa
Flowering: 8-9 weeks
Indoor Yield: ~1.6-1.9 oz/ft²
Outdoor Yield: ~17-20 oz/plant
Height: ~50-60 in
Harvest: End of September
Effect: Creative, Euphoria
Genetics: Haze × Northern Lights × Shiva Skunk

Why Grow Jack Herer?

Balanced high: strong creativity and euphoric effects without being too heavy.
Flavor profile that stands out: pine + spice, classic but sharp.
Reliable flowering time (8-9 weeks) for growers who want faster turnaround.
Good yields indoors and out with the right care.
Respected lineage: Haze and Northern Lights bring tried-and-true traits.

Setup & Growing Conditions

Indoor Setup

Tent: 2×2 ft or larger (ideal 3×3)
Lighting: Full-spectrum LED, mid-high intensity (≈ 400-600 W eq.)
Ventilation: Strong inline fan + carbon filter
Air Circulation: Oscillating fans for canopy breeze
Soil / Medium: Well-draining soil or coco + perlite mix
Pots: 3-5 gal fabric or equivalent
Nutrients: Balanced veg + bloom feed; light starter feeds
Water: pH around 6.2-6.6

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.

Outdoor Notes

Best in warm, dry to moderately humid climates
Sow so that plants finish by end of September to avoid fall mold/rain risks
Soil rich in organic matter, good drainage

Jack Herer Grow Cycle Conditions (Quick Reference)

Stage	Light Schedule	Temp (°F)	Humidity (%)	Notes
Seedling (Week 1)	18–24 hrs (low intensity)	72–77	65–70	Keep soil moist, no nutrients (Cal-Mag only if coco).
Early Veg (Week 2–3)	18/6	73–78	60–65	Begin light veg feed (¼ strength). Optional LST.
Late Veg (Week 4)	18/6 (~500 PPFD)	73–78	50–55	Full veg nutrients, prep for 12/12.
Flower Transition (Week 5)	12/12	72–78	45–50	Switch to bloom nutrients (P & K boost, lower N).
Flower Build (Week 6–7)	12/12 (~600–700 PPFD)	70–77	40–45	Bud stacking, trichomes form, strong aroma.
Ripening (Week 8)	12/12 (~700–800 PPFD)	67–73	40	Trichomes cloudy, pistils turning orange.
Final Flush (Week 9)	12/12	65–70	35–40	Flush with plain pH’d water for 5–7 days, harvest when trichomes mostly cloudy with 10–15% amber.
Dry & Cure	Darkness	60	55	Dry 10–14 days, cure in jars for 3–4 weeks.

Week 1: Seedling Stage

Jack Herer sprouts with cotyledons and its first serrated leaves. Keep temps steady at 72–77°F, high humidity (65–70%), and gentle airflow. No nutrients yet—just light watering to encourage root anchoring.

Germination: Use paper towel method, warm (70-75°F)
Light: Low intensity, 18-24 hours
Humidity: ~65-70%
Water: Gentle; avoid overwatering

Week 2: Early Veg + Optional LST

The plant develops fan leaves and a stronger stem. Maintain 18 hours of light, 73–78°F temps, and 60–65% humidity. Start light veg nutrients (¼ strength) and consider LST to shape a wider canopy.

Growth: First true leaves, internodes start stabilizing
Begin Low Stress Training (LST) for a flatter canopy
Nutrients: Light veg mix

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

Week 4: Pre-Flower & Final Veg Training

Jack Herer reaches 12–18 inches with bushy growth. Full-strength veg feed and ~500 PPFD light intensity help it thrive. Trim lower growth for airflow and prepare to flip to 12/12 flowering.

Height: ~12-18 in at this point indoors
Full veg feed strength, increase light intensity
Clean up lower foliage for airflow
Finish LST or use SCROG

Week 5: Flower Begins

The flip to 12/12 initiates stretch and pistil formation. Temps stay 72–78°F, humidity drops to 45–50%. Switch to bloom nutrients with more phosphorus and potassium while lowering nitrogen.

Flip to 12/12 light cycle
Switch to bloom nutrients (more P & K)
Monitor stretch; Jack Herer pushes appreciable vertical growth

A visual showing early cannabis bud development small white pistils, forming calyxes, and early trichome frost

Week 6: Bud Sites & Trichome Development

Bud sites stack up and trichomes begin frosting. Maintain 70–77°F temps and 40–45% humidity under ~600–700 PPFD. The aroma shifts to piney and spicy as colas start thickening.

Buds show at many nodes
Trichome frosting begins
Aroma intensifies: more pine + spice notes

Week 7: Bud Fattening & Aroma Surge

Buds swell, calyxes fill in
Spicy-pine and resin aromas really pop
Maintain humidity ~40-50% to avoid mildew

Week 8: Peak Flower & Ripening Begins

Buds swell and pistils turn orange. Trichomes turn mostly cloudy, signaling peak potency. Keep temps slightly cooler (67–73°F) and humidity at ~40% to enhance resin and terpene preservation.

Pistils begin darkening, trichomes mostly cloudy
Bud density improves; firmness increases

Image showing cannabis trichomes at different maturity stages: clear, cloudy, and amber

Week 9: Final Flush & Ripeness Check

Reduce nutrients and flush with plain, pH’d water for 5–7 days. Humidity drops to 35–40%, temps 65–70°F. Monitor trichomes: harvest when mostly cloudy with ~10–15% amber for balanced effects.

Flush plants (pH’d water only) for last 5-7 days
Look for mostly cloudy trichomes with some amber for desired effect
Time harvest for optimal aroma and potency

Harvest & Curing

Chop plants at the end of Week 9 (or late September outdoors). Dry slowly at 60°F / 55% RH for 10–14 days, then cure in jars for at least 3–4 weeks. Expect resinous, pine-spice buds with euphoric, creative effects.

Harvest: End of September (outdoor), Week 9 indoors
Dry: ~60°F / ~55% RH for 10-14 days in darkness
Cure: Jar with daily burps first week, then every few days afterward
Flavor peaks after curing: piney, spicy, sweet undertones

Final Thoughts

Jack Herer is a solid choice if you want a classic, balanced hybrid with personality. It’s not overly complicated to grow, especially with training and good environment control. The yield, flavor, and effects make the extra effort worthwhile.

If you’ve been looking up how to grow Jack Herer strain, this diary gives you the full path from germination to jar.

👉 Shop Jack Herer seeds at Hypno Seeds
👉 Browse more Hybrid Seeds
🔗 Learn more about Jack Herer on Leafly

FAQ: Growing Jack Herer Seeds

How long does Jack Herer take to flower?
8-9 weeks indoors; harvest around end of September outdoors.

How tall does Jack Herer grow?
Approximately 50-60 inches under good conditions.

Is Jack Herer difficult to grow?
Moderately easy. Needs good airflow and training (LST/SCROG) to maximize yields and prevent spindly growth.

What yields can I expect?
Indoors: ~1.6-1.9 oz/ft². Outdoors: ~17-20 oz per plant under optimal conditions.

What does Jack Herer taste like?
Pine, spice, and herbal notes with a sweet-earthy background.

What effects does Jack Herer have?
Creative, euphoric, clear-headed, great for daytime or productive sessions.