How to Grow Amnesia Haze
A tall, slow-finishing haze with high yield potential and strict environmental demands.
Growing, buying or possessing cannabis and seeds is legal only in some places. Check the law where you live before acting on this information.
Amnesia Haze rewards patience and space, but punishes shortcuts. It stretches aggressively, flowers for 11–12 weeks (not 10), and needs rock-solid humidity control in late bloom. Don't veg it like an indica. Expect tall plants, big yields if you dial it in, and heartbreak if you ignore bud rot risk or harvest early.
What Amnesia Haze is
Amnesia Haze is a photoperiod sativa-dominant hybrid best known for winning the High Times Cannabis Cup in 2004. It rose to prominence in Dutch coffeeshops in the mid-2000s and remains a reference point for uplifting, cognitively intense effects. Multiple seed banks sell versions under the name—Barney's Farm, Royal Queen Seeds, Soma Seeds and others—and phenotypes differ noticeably between suppliers.
The strain is characterized by tall, lanky growth with long internodes, thin-fingered leaves, and airy, resinous colas at maturity. It is not a compact or quick-finishing plant.
Note on lineage and effects: The exact parentage of Amnesia Haze is not fully documented and varies by breeder Disputed. The popular idea that strain names reliably predict effects is unreliable; two seeds from the same pack can behave differently, and a "sativa-dominant hybrid" label does not precisely predict subjective effects Disputed.
Why growers choose it
Yield potential. Under controlled conditions, Amnesia Haze produces large harvests. Barney's Farm quotes 600–700 g/m² indoors and up to 1.2 kg per plant outdoors. These are best-case figures; typical results depend heavily on light, nutrients, disease management and grower skill.
Potency. Lab results from tested samples typically show THC in the 18–22% range with low CBD Weak / limited[1]. Note: cannabinoid percentages alone do not predict subjective potency or effect onset.
Distinctive aroma and flavor profile. Amnesia Haze is known for citrus and earthy-spicy character, commonly attributed to terpinolene, myrcene and ocimene Weak / limited[1]. This is one reason growers seek the strain, though terpene profiles alone do not determine effects in a predictable way.
What it is not good for: Small spaces, cold climates, fast turnarounds, or growers who want a compact plant. If you need shorter, faster results, consider an autoflowering strain or an indica-dominant hybrid instead.
When to start and choose your environment
Indoors: You can start any time of year. Maintain 24–28°C during vegetative and flowering stages and keep humidity below 50% in late flower to prevent bud rot.
Outdoor (Northern Hemisphere): Germinate indoors in March–April, transplant outdoors after the last frost (typically May), and expect harvest in late October or early November. Amnesia Haze needs a long season and struggles in climates where autumn turns wet and cold before mid-October [2].
Outdoor (Southern Hemisphere): Flip the calendar—germinate August–September, harvest April–May.
Greenhouse: Growers in temperate climates often use light deprivation to force earlier flowering and avoid autumn rot.
Step-by-step growing guide
Germination (days 1–5)
Use the paper towel method or direct-to-soil in a small pot. Keep at approximately 24°C and lightly moist, not waterlogged.
Seedling stage (weeks 1–2)
Provide 18/6 or 20/4 light schedule. Use low light intensity (~200 µmol/m²/s). Do not apply nutrients yet—seedlings live off the seed and starter medium.
Vegetative growth (weeks 2–6)
Switch to full vegetative lighting (400–600 µmol/m²/s). Keep this phase short. Amnesia Haze stretches aggressively, so 3–4 weeks after the seedling stage is usually sufficient for a 1.2 m × 1.2 m tent. Top the plant once or twice at the 4th–5th node to encourage lateral branching.
Feed a nitrogen-forward vegetative nutrient mix at moderate strength (EC ~1.2–1.4 in hydroponics, or standard veg dose in soil). Target pH: 5.8–6.2 in hydro/coco, 6.2–6.8 in soil.
Flip to 12/12 (week 6)
Switch lighting to 12 hours on, 12 hours off. Expect the plant to double or triple in height over the next 3–4 weeks. This stretch is the single biggest surprise for new Amnesia Haze growers. Install a ScrOG net or trellis before the flip and tuck branches through it to keep the canopy even.
Early flower (weeks 1–4 of 12/12)
Transition to a bloom nutrient formula: lower nitrogen, raise phosphorus and potassium. Keep humidity around 50–55% and temperatures 24–26°C.
Mid to late flower (weeks 5–10)
Buds fill in during weeks 6–8, but Amnesia Haze finishes slowly—the last 2–3 weeks add significant weight. Drop humidity to 40–45% to prevent botrytis (bud rot), which thrives in dense sativa colas [3]. Monitor trichomes with a jeweler's loupe or USB microscope.
Harvest (weeks 10–12 of flower)
Harvest when approximately 70–90% of trichomes are cloudy with some amber, depending on desired effect. Earlier harvest tends to produce more uplifting effects; later harvest produces heavier, more sedating effects Weak / limited. Dry at 18–20°C and 55–60% relative humidity for 10–14 days, then cure in glass jars for at least 2–4 weeks.
Common mistakes to avoid
Vegging too long. Growers accustomed to indicas often veg for 6–8 weeks, then panic when Amnesia Haze hits the light. 3–4 weeks is plenty.
Underestimating flowering time. Seed packets say 10 weeks; reality is typically 11–12 weeks. Chopping early costs yield Weak / limited.
Overfeeding nutrients. Hazes are sensitive to nutrient burn, especially nitrogen in late vegetative growth and early flower. Start at 60–70% of the recommended dose and increase gradually.
Ignoring humidity in late flower. The long, dense colas trap moisture. Bud rot on Amnesia Haze is preventable with a dehumidifier and active airflow [3].
Assuming all seeds are identical. Multiple seed banks sell Amnesia Haze under the same name with different phenotypes. Buy from a breeder whose phenotype has been reviewed by growers, and expect variation between individual seeds.
Related techniques and reading
ScrOG (Screen of Green). Nearly essential for controlling stretch and evening out the canopy on Amnesia Haze.
Topping and FIMing. Use once or twice during vegetative growth only; do not top after the stretch begins.
Selective defoliation. Careful removal of large fan leaves in mid-flower can improve light penetration. Aggressive defoliation is debated among growers Disputed.
Light deprivation. Useful for greenhouse growers in cooler climates who want to finish before autumn rain.
Curing. Amnesia Haze particularly benefits from a long cure—the harshness of fresh Haze mellows significantly after 6–8 weeks in jars Anecdote.
Related haze strains: Learn more about the original Haze, Super Silver Haze, and Haze #47.
Sources
- Peer-reviewed Hazekamp, A., & Fischedick, J. T. (2012). Cannabis - from cultivar to chemovar. Drug Testing and Analysis, 4(7–8), 660–667.
- Peer-reviewed Bugbee, B., et al. (2020). Optimizing environments for cannabis cultivation: photosynthetic response to light and CO₂. Frontiers in Plant Science, 11, 646.
- Book Cervantes, J. (2015). The Cannabis Encyclopedia: The Definitive Guide to Cultivation and Consumption of Medical Marijuana. Van Patten Publishing.
How this page was made
Generation history
Drafted with AI assistance and checked by a separate automated fact-check pass. Not every article has been read by a person. See how articles are made.
Related
- Autoflowering Cannabis Cultivation — Age-based flowering cannabis for faster harvests and simplified growing.
- Curing Cannabis — The slow, low-effort post-harvest step that turns harsh, grassy flower into smooth, aromat...
- How to Grow Haze — Long-flowering sativas demand patience, space, and climate awareness to reach their full p...
- pH Management in Cannabis Cultivation — Control nutrient availability by maintaining pH in your growing medium.
- Super Silver Haze — Sativa-leaning haze hybrid with terpinolene dominance and 10–11 week flowering.
- VPD (Vapor Pressure Deficit) Basics — How to use vapor pressure deficit to manage plant transpiration and prevent humidity-relat...