How to Grow Amnesia Haze
A practical guide to growing Amnesia Haze, a sativa-dominant hybrid that rewards patience, warmth, and vertical space with high yields and long flowering.
Amnesia Haze is not a beginner strain. It stretches like a beanstalk, flowers for 10-12 weeks, and gets fussy about humidity and nutrients. But if you have the ceiling height, the patience, and a warm climate (or a good tent), it produces some of the biggest, most pungent sativa yields you can grow at home. Most of what you read about "exact" flowering times and yields is optimistic marketing copy from seed banks — actual results depend heavily on phenotype, since Amnesia Haze is not a stabilized F1.
What Amnesia Haze is
Amnesia Haze is a sativa-dominant photoperiod hybrid that rose to fame in Dutch coffeeshops in the mid-2000s and won the High Times Cannabis Cup in 2004 for Barney's Farm [1]. Its lineage is usually described as a mix of Southeast Asian and South Asian sativas crossed with Jamaican and Hawaiian genetics, though exact parentage varies by breeder and is not fully documented Disputed.
Several seed banks sell versions under the same name (Royal Queen Seeds, Barney's Farm, Soma Seeds, others), and phenotypes differ noticeably between them [2]. Expect a tall, lanky plant with long internodes, thin fingered leaves, and airy, resinous colas at maturity.
Why growers choose it
Three real reasons:
- Yield. Under good conditions Amnesia Haze produces large harvests — seed banks quote 600-700 g/m² indoor and up to 1.2 kg per plant outdoor, though these are best-case numbers, not averages [1][2].
- Potency. Independent lab data from Dutch coffeeshop samples and seed bank testing typically shows THC in the 18-22% range, with low CBD Weak / limited[3].
- Terpene profile. Amnesia Haze is known for citrus and earthy-spicy notes, generally dominated by terpinolene, myrcene, and ocimene in the samples that have been analyzed Weak / limited[3]. Note: the popular claim that terpene profile predicts effects in a precise way is folklore, not established science Disputed.
What it is not good for: small spaces, cold climates, impatient growers, or anyone who wants a fast turnaround. If those are your constraints, consider an autoflower or an indica-dominant hybrid instead.
When to start
Indoor: any time of year, provided you can hold 24-28°C during veg and flower and keep humidity below 50% in late flower to avoid bud rot.
Outdoor (Northern Hemisphere): germinate indoors in March-April, transplant outside after last frost (typically May), and expect harvest in late October or early November. Amnesia Haze needs a long season and does poorly in climates where autumn turns wet and cold before mid-October [4].
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 dodge autumn rot.
How to grow it: step by step
1. Germination (days 1-5)
Paper towel or direct-to-soil in a small pot. Keep at ~24°C and lightly moist, not wet.
2. Seedling (weeks 1-2)
18/6 or 20/4 light schedule. Low light intensity (~200 µmol/m²/s). Do not feed nutrients yet — seedlings live off the seed and starter medium.
3. Vegetative growth (weeks 2-6)
Switch to full veg lighting (400-600 µmol/m²/s). Amnesia Haze stretches aggressively, so keep veg short — 3-4 weeks after seedling stage is usually enough for a 1.2m x 1.2m tent. Top the plant once or twice at the 4th-5th node to encourage lateral growth. Feed a nitrogen-forward nutrient mix at moderate strength (EC ~1.2-1.4 in hydro, or standard veg dose in soil). Target pH: 5.8-6.2 hydro/coco, 6.2-6.8 soil [5].
4. Flip to flower (week 6)
Switch to 12/12. Expect the plant to double or triple in height over the next 3-4 weeks. This is the single most common 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.
5. Early flower (weeks 1-4 of 12/12)
Transition nutrients to a bloom formula, lower nitrogen, raise phosphorus and potassium. Keep humidity around 50-55% and temps 24-26°C.
6. Mid to late flower (weeks 5-10)
Buds start to 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 loves dense sativa colas [6]. Watch trichomes with a jeweler's loupe or USB microscope.
7. Harvest (weeks 10-12)
Harvest when ~70-90% of trichomes are cloudy with some amber, depending on the effect you want. Earlier harvest = more clear-headed; later = heavier, more sedating Weak / limited. Dry at 18-20°C and 55-60% RH for 10-14 days, then cure in glass jars for at least 2-4 weeks.
Common mistakes
- Vegging too long. Growers used to indicas veg for 6-8 weeks and then panic when the plant hits the light. 3-4 weeks veg is plenty.
- Underestimating flowering time. Package says 10 weeks; reality is often 11-12. Chopping early costs you 15-25% of the final weight Weak / limited.
- Overfeeding. Hazes are sensitive to nutrient burn, especially nitrogen in late veg and early flower. Start at 60-70% of the recommended dose and work up.
- Ignoring humidity in late flower. The long, dense colas trap moisture. Bud rot on Amnesia Haze is heartbreaking and preventable with a dehumidifier and airflow [6].
- Assuming all Amnesia Haze seeds are the same. They are not. Buy from a breeder whose phenotype you have seen reviewed, and expect variation between seeds [2].
Related techniques
- ScrOG (Screen of Green): Almost mandatory for controlling Amnesia Haze's stretch and evening out the canopy.
- Topping and FIMing: Use once or twice during veg. Do not top after the stretch is finished.
- Defoliation: Selective removal of large fan leaves in mid-flower can improve light penetration, but aggressive schwazzing is contested Disputed.
- Light deprivation: Useful for greenhouse growers in cooler climates who want to finish before autumn rain.
- Curing cannabis: Amnesia Haze in particular benefits from a long cure — the harshness of fresh Haze mellows dramatically after 6-8 weeks in jars Anecdote.
Sources
- Practitioner Barney's Farm. Amnesia Haze strain page (breeder documentation, flowering time, yield, awards).
- Practitioner Royal Queen Seeds. Amnesia Haze strain profile and grow information.
- Peer-reviewed Hazekamp, A., & Fischedick, J. T. (2012). Cannabis - from cultivar to chemovar. Drug Testing and Analysis, 4(7-8), 660-667.
- Book Cervantes, J. (2015). The Cannabis Encyclopedia: The Definitive Guide to Cultivation and Consumption of Medical Marijuana. Van Patten Publishing.
- Peer-reviewed Bugbee, B., et al. (2020). Optimizing environments for cannabis cultivation: photosynthetic response to light and CO2. Frontiers in Plant Science, 11, 646.
- Peer-reviewed Punja, Z. K., et al. (2019). Bud rot caused by Botrytis cinerea on cannabis (Cannabis sativa L.) inflorescences. Canadian Journal of Plant Pathology, 41(3), 379-395.
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