Written by Ad OpsHistory and Origins
Arjan's Ultra Haze #1 emerged from Green House Seeds in Amsterdam during the mid-2000s, a period often described as a renaissance for Haze varieties in European coffeeshops. Guided by founder Arjan Roskam's long-standing pursuit of uplifting, long-lasting sativas, the breeding team refined phenotypes that balanced classic Haze electricity with composure and clarity. The result was a cultivar designed to deliver cerebral elevation without the jittery edge that can plague less-polished Haze crosses.
The strain quickly gained a reputation among connoisseurs for its marathon duration and contemplative mood. In Amsterdam menus and European forums, it was frequently called a thinking person's sativa, prized for extended sessions and creative work. That reputation mirrors Green House Seeds' own description of the experience as extremely peaceful and chill, ideal for relaxation and reflection, yet not to be underestimated for potency.
As Haze lines spread from California to Europe in the late 20th century, breeders selectively combined Southeast Asian, South American, and old-school Haze stock to stabilize desirable traits. Arjan's Ultra Haze #1 is a culmination of that iterative selection, offering the classic incense-and-citrus bouquet with a contemporary emphasis on smoothness. Its persistence in seed catalogs and grow logs for well over a decade speaks to its staying power and the niche it fills for patient, meditative sativa fans.
While specific awards and showings are secondary to its everyday utility, the cultivar's presence in the Green House Seeds lineup underscores its importance to their sativa heritage. The company is known for dialing in phenotypes that scale for both hobbyists and commercial rooms, and Ultra Haze #1 typifies that approach. Its history is not about novelty; it is about refining a timeless Haze experience for consistent, repeatable results.
Genetic Lineage
Green House Seeds describes Arjan's Ultra Haze #1 as part of their Haze family, carrying deep sativa heritage. Although different sources over the years have listed varying parent lines for Ultra Haze projects, the consensus is that this cultivar draws from multiple Haze-dominant parents with Southeast Asian influence. The aim was to retain the unmistakable Haze headspace while elongating the sweet, incense-like profile and moderating raciness.
Classic Haze lines historically trace to blends of Colombian, Mexican, Thai, and South Indian genetics, later refined in Europe. Many of Green House's Haze-leaning releases also incorporate Southeast Asian elements such as Laos or Cambodian expressions, chosen for electric uplift and long flowering. Arjan's Ultra Haze #1 fits that template: long internodes, soaring vertical growth, and a terpene bias consistent with terpinolene-forward sativas.
It is accurate to frame Arjan's Ultra Haze #1 as a multi-Haze hybrid rather than a simple two-way cross. The cultivar likely reflects cumulative selection across several generations to stabilize temperament and aroma while managing flower density. In practical terms, this lineage yields nuanced floral-citrus-spice aromatics with a sustained cerebral trajectory over 2 to 3 hours for most users.
The genetic emphasis on equatorial sativa traits carries cultivation implications that growers should note. Expect a pronounced stretch after flip, responsive lateral growth under training, and a flowering window toward the long end of the spectrum. The lineage also tends to produce resin with modest CBD and trace THCV potential, a profile common to classic Haze families.
Appearance
Arjan's Ultra Haze #1 exhibits classic sativa morphology from seedling to late flower. Plants develop elongated internodes of roughly 3 to 7 cm under adequate light, with narrow leaflets and a high leaf-to-stem ratio early in vegetative growth. Once flowered, expect a 200 to 300 percent stretch, especially in untrained or high-intensity environments.
The buds themselves are long, tapered, and less compact than typical indica hybrids. Cola structures often present as stacked calyxes with some foxtailing under high heat or late flower intensity, a common Haze trait rather than a sign of stress. Trichome coverage is abundant and glassy, giving a shimmering appearance that can make the flowers look frosted despite their relatively open structure.
Colors range from lime to olive green with occasional lavender hues in cooler night temperatures toward the end of flower. Pistils are usually bright orange to tangerine and can be prolific, accenting the lean, tapered buds. Sugar leaves are slender and may take on a silvery sheen in strong resin producers.
In indoor grows, untrained plants can hit 100 to 160 cm with ease, while outdoors they can exceed 200 to 300 cm in long-season climates. Trellising or yo-yo support is recommended for the largest colas in weeks 10 to 14 of flower to prevent lean. Overall, the aesthetic is quintessential Haze: elegant, elongated, and resin-forward without the brick-like density of indica-dominant varieties.
Aroma
The aroma profile leans into quintessential Haze territory with elevated complexity. On first inspection, expect a fusion of sweet citrus rind, fresh-cut cedar, and light floral incense. Grind the flower and the bouquet lifts sharply, adding notes of anise, basil, and a subtle green mango accent.
As the cure progresses past four weeks, the top notes smooth into a more cohesive perfume. The cedar-sandalwood thread gains prominence, while the citrus becomes more candied and less astringent. At eight weeks of cure, the jar aroma often shows a balanced trio of pine, lemon, and spice, with a lingering sweet tea character.
Terpinolene and ocimene drive much of the bright, airy lift, supported by myrcene's herbal depth and limonene's zesty pop. Beta-caryophyllene contributes faint peppery warmth that becomes obvious after grinding. In well-grown examples, total terpene content of 1.5 to 3.0 percent by weight is common, producing a room-filling scent when breaking up a single gram.
Environmental conditions during late flower can nudge the profile in distinct directions. Higher day temperatures and rapid dry-downs can flatten floral nuance, while cooler nights and a slow dry at around 60 percent RH preserve the incense and citrus-lime top notes. Proper storage at 15 to 20 degrees Celsius in airtight containers helps maintain aromatic integrity over months.
Flavor
The flavor closely mirrors the aroma but with a clearer division between top notes and finish. The inhale often begins with lemon peel, sweet basil, and pine needle, delivering a bright first impression. On the exhale, a smooth cedar and light sandalwood undertone emerges, followed by a white-pepper tickle that suggests caryophyllene.
In vaporization at 170 to 185 degrees Celsius, the citrus-floral envelope is prominent and long-lasting. At higher temperatures above 200 degrees Celsius, expect a shift toward wood and pepper as the terpenes degrade and heavier compounds dominate. Users frequently note a clean, lingering aftertaste reminiscent of green tea with a slice of lime.
Curing has a measurable effect on flavor clarity. A four- to eight-week cure typically enhances sweetness and reduces chlorophyll-associated harshness, improving perceived smoothness by a noticeable margin. Properly dried flower should burn evenly with pale ash and minimal throat bite, reflecting balanced mineral content and a thorough finish.
Concentrates made from Arjan's Ultra Haze #1 often deliver a brighter, terpene-tilted flavor compared to heavier strains. Live resins and rosin can concentrate the lemon-incense spectrum, making them ideal for users who prioritize flavor over density. Even in full-spectrum extracts, the finish trends clean and airy rather than syrupy or musky.
Cannabinoid Profile
Arjan's Ultra Haze #1 is typically THC-dominant, with most lab reports and grower accounts placing potency in the high teens to low twenties by percentage. A reasonable expectation for well-grown flower is approximately 16 to 22 percent THC by dry weight, translating to 160 to 220 milligrams of THC per gram of flower. Under highly optimized conditions, select phenotypes can report above 22 percent, but averages in the 18 to 20 percent band are common for long-flowering sativas.
CBD levels are generally low, commonly under 1.0 percent and often below 0.3 percent in THC-dominant cuts. CBG may present in the 0.3 to 1.0 percent range, a profile consistent with many Haze-derived cultivars. Trace THCV can appear in some sativa-heavy phenotypes, typically measured between 0.2 and 0.8 percent when present, though this varies substantially across seed lines and growth environments.
Cannabinoid expression is sensitive to light intensity, harvest timing, and post-harvest handling. Harvesting at peak milky trichome with 5 to 10 percent amber typically prioritizes heady clarity, while pushing to 10 to 20 percent amber may deepen body warmth at a small cost to perceived brightness. Overdrying or high-temperature drying can reduce measured cannabinoids by accelerating decarboxylation and volatilization, potentially lowering total measured potency by several percentage points.
From a dosing perspective, a single 0.1-gram inhaled portion at 18 percent THC delivers approximately 18 milligrams of THC pre-loss, with bioavailability for inhalation commonly estimated in the 20 to 40 percent range. That equates to a ballpark of 3.6 to 7.2 milligrams of absorbed THC per small session, depending on consumption method and individual variability. Users sensitive to sativa effects should keep these calculations in mind, as the clarity and length of Ultra Haze #1 can make redosing tempting.
Terpene Profile
Arjan's Ultra Haze #1 tends to show a terpinolene-forward terpene profile, a hallmark of many classic Haze cultivars. Typical dominant terpenes and ranges observed in sativa-dominant lab reports include terpinolene at approximately 0.3 to 1.0 percent by weight, myrcene at 0.2 to 0.8 percent, and limonene at 0.2 to 0.6 percent. Supporting contributors often include ocimene at 0.1 to 0.5 percent, beta-caryophyllene at 0.1 to 0.4 percent, alpha-pinene at 0.1 to 0.3 percent, and linalool in trace to 0.2 percent.
The synergy of these terpenes aligns with the strain's perceived effects. Terpinolene and ocimene are associated with bright, airy, and occasionally effervescent sensory impressions, while limonene supports mood elevation and perceived energy. Myrcene adds herbal depth and can subtly modulate onset, and caryophyllene introduces a peppery edge and interacts with CB2 receptors.
Total terpene content for well-grown, slow-dried flower commonly falls between 1.5 and 3.0 percent by weight. Exceeding 3 percent is achievable in optimal environments with gentle handling and rapid cold storage post-trim. Concentrates derived from fresh-frozen material can display terpene concentrations an order of magnitude higher than dried flower by percentage, though absolute quantities vary.
For vaporization, keeping temperatures around 170 to 190 degrees Celsius preserves the high-volatility fraction of terpinolene and ocimene. Combustion at higher temperatures favors caryophyllene and pinene notes but can shorten the bright top-note window. Careful storage below 20 degrees Celsius, away from UV exposure, reduces terpene loss over time and preserves the signature incense-citrus profile.
Experiential Effects
Consistent with the live information from Green House Seeds' retail partners, Arjan's Ultra Haze #1 is extremely peaceful and chill, excellent for relaxation and reflection. The high typically begins with a clear, buoyant lift within minutes of inhalation, sharpening focus without the jitter. Users often describe a sense of mental spaciousness and smooth motivation rather than urgent stimulation.
At its peak, the experience maintains clarity while softening bodily tension, which distinguishes it from racier Hazes. Creative tasks, journaling, long walks, and ambient music pair well with the mood profile. The ride commonly extends 2 to 3 hours for inhaled formats, with a gentle taper rather than a hard drop-off.
In social settings, the strain tends to promote easy conversation and introspective pauses rather than exuberant chatter. For some, it functions as a productive sativa suitable for daytime use; for others, it becomes an evening wind-down when quiet contemplation is desired. The mellow nature should not be underestimated, as increases in dose can shift the experience from serene to intensely cerebral.
Side effects mirror those of THC-dominant sativas. Dry mouth and dry eyes are common, and at higher doses susceptible users may notice transient increases in heart rate and a sharper edge to the headspace. New or anxiety-prone consumers do well starting with small inhalations or low-dose edibles to calibrate comfort.
Potential Medical Uses
While not a substitute for medical care, Arjan's Ultra Haze #1's profile suggests several potential wellness applications. The bright, terpinolene- and limonene-influenced mood lift may help users manage day-to-day stress or low motivation. Many patients report that clear, functional sativas can support focus for tasks that benefit from sustained attention without sedation.
For mood-related concerns, the blend of an uplifting headspace with an unusually calm body feel can be valuable. Individuals who find some Hazes too racy may appreciate this cultivar's gentler affect, especially during afternoon slumps. In anecdotal reports, users mention improved outlook and reduced rumination, consistent with the strain's reflective character.
Pain and tension relief are not the primary strengths of this variety, but mild neuropathic discomfort and tension-type headaches may respond to the distraction and easing provided by the head high. Migraines are highly individual; some users find high-terpinolene sativas helpful at prodrome, while others prefer non-stimulating profiles. As always, patient-specific tracking is recommended to map triggers and relief patterns.
For fatigue and lethargy, the clear uplift and non-sedating character can be advantageous during daytime. However, because THC can impair short-term memory and coordination, medical users should titrate carefully when productivity and safety are priorities. Sensible starting doses for new patients are in the 2.5 to 5.0 milligram THC range, with gradual increases as needed.
Individuals sensitive to anxiety should approach with care. Although many find Arjan's Ultra Haze #1 notably peaceful, higher doses can become intensely cerebral. Pairing with CBD-rich material or using lower-temperature vaporization sessions can moderate that edge for those who prefer a softer onset.
Comprehensive Cultivation Guide
Arjan's Ultra Haze #1 is a true sativa in the garden, rewarding patient growers with exceptional resin and complex aroma. Expect a long flowering window, significant stretch, and heavy responsiveness to training. With planning and environmental control, yields can be impressive relative to the airy structure typical of Hazes.
Growth pattern and timing
- Vegetative phase: 3 to 6 weeks is typical for indoor, though many growers shorten veg to manage height. Under 18/6 light, plants develop rapidly with narrow, serrated leaves and long internodes.
- Flowering phase: 12 to 14 weeks for most phenotypes after flip to 12/12. Outdoor harvest in the Northern Hemisphere often lands from late October to early November, requiring a dry climate or greenhouse.
Environment and climate targets
- Temperature: 24 to 28 degrees Celsius day, 18 to 22 degrees night in veg; allow a 2 to 4 degree drop at lights off. In late flower, slightly cooler nights can tighten structure and boost color.
- Humidity: 60 to 70 percent in seedlings, 50 to 60 percent in veg, 40 to 50 percent in early to mid flower, and 35 to 45 percent in late flower. The long bloom requires consistent vapor pressure deficit management to prevent botrytis.
- Light: Aim for 600 to 900 µmol m−2 s−1 PPFD in veg and 800 to 1100 µmol m−2 s−1 in flower for LED grows. Keep daily light integral around 35 to 50 mol m−2 day−1 in veg and 40 to 60 mol m−2 day−1 in flower.
Feeding and root zone management
- pH: 6.2 to 6.8 in soil, 5.8 to 6.2 in hydro and coco. Stable pH is crucial for calcium and magnesium uptake during stretch.
- EC: 1.0 to 1.4 mS cm−1 in early veg, rising to 1.4 to 1.8 in peak flower. Sativas generally prefer moderate feed; avoid overfeeding nitrogen past week 3 of bloom to preserve terpene expression.
- Calcium and magnesium: Supplement as needed, especially under high-intensity LED lighting. Deficiency can show as interveinal chlorosis and brittle leaves mid-flower.
Training and canopy control
- Topping and mainlining: Top once or twice in veg to establish 4 to 8 main branches. This reduces apical dominance and distributes vigor across the canopy.
- Low-stress training: Bend and tie branches out to encourage lateral fills. A screen of green (SCROG) approach can produce even canopies and improve light penetration.
- Supercropping: Gentle stem kinks during early stretch can control height without stalling growth. Avoid aggressive bending after week 3 of flower.
Stretch and space planning
- Expect 2x to 3x stretch after flip; plan final plant height accordingly. Keep LED fixtures 30 to 50 cm above canopy at target PPFD to minimize fox tails driven by heat or light stress.
- Use trellis layers to support long colas in weeks 10 to 14. Strategic defoliation in weeks 3 and 6 can open airflow while preserving photosynthetic area.
Irrigation strategies
- In soil, water to 10 to 20 percent runoff and allow pots to lighten substantially between irrigations. In coco, higher frequency with lower volume maintains consistent EC and root oxygen.
- Root temperature around 20 to 22 degrees Celsius supports steady metabolism. Avoid cold floors and stagnant saucer runoff to prevent root pathogens.
Yield expectations
- Indoor yields of 500 to 700 grams per square meter have been reported by experienced growers using SCROG and high-intensity lighting. Phenotype and environment strongly influence outcomes due to the long bloom.
- Outdoors, plants can exceed 1.5 to 3.0 meters in height with proper season length and may produce several hundred grams per plant, with kilogram-class plants possible in ideal, arid climates. Greenhouse cultivation extends the season and guards against late autumn rain.
Pest and disease management
- The extended flowering time increases exposure risk to spider mites, thrips, and powdery mildew. Implement integrated pest management: sticky cards, predator mites, and regular leaf inspections.
- Bud rot (Botrytis) is the primary late-flower threat. Maintain robust airflow, avoid large wet-dry swings, and consider selective leaf removal around dense cola cores from week 9 onward.
CO2 and advanced controls
- Supplemental CO2 at 1000 to 1200 ppm can increase growth rate and resilience in high-light rooms. Maintain consistent VPD to match elevated photosynthetic rates.
- Dehumidification capacity must scale with transpiration; sativas can transpire heavily during stretch. Program environmental setpoints to track lights-on and lights-off differentials closely.
Nutrient schedule notes
- Veg: Favor calcium-rich base nutrients with nitrogen sufficient for rapid growth; include silica for stem strength. Micronutrient balance (iron, manganese) is important to avoid pale new growth under bright light.
- Early flower (weeks 1 to 3): Transition from N to P-K emphasis; maintain magnesium and sulfur for chlorophyll and terpene synthesis.
- Mid to late flower (weeks 4 to 12+): Moderate EC prevents salt buildup; a slight reduction late flower can sharpen flavor. Many growers run a 7 to 14 day finish with low EC to encourage a clean burn.
Harvest timing and processing
- Visual cues: Sativa trichomes often take longer to amber; aim for cloudy dominance with 5 to 15 percent amber depending on desired balance. Pistils may continue to push late into bloom; rely on trichomes for precision.
- Drying: Target approximately 18 to 21 degrees Celsius and 55 to 62 percent RH for 10 to 14 days. Slow drying preserves terpinolene and ocimene, which are more volatile than heavier terpenes.
- Curing: Burp sealed containers daily for the first week, then weekly for the next month. A 4 to 8 week cure deepens cedar and incense notes and smooths the finish.
Common mistakes and how to avoid them
- Over-veg and insufficient training lead to canopy chaos; plan structure early. Use topping and SCROG to keep tops within the light's sweet spot.
- Overfeeding late-flower can mute aromatics and add harshness. Keep EC moderate and ensure thorough runoff to prevent substrate salinity.
- High humidity late in bloom invites botrytis; invest in airflow and dehumidification. Space colas, prune larfy undergrowth, and monitor microclimates within dense sections.
From seed to harvest, Arjan's Ultra Haze #1 rewards patience and planning. Growers who embrace its sativa cadence and manage environment proactively can achieve excellent quality with a signature Haze profile. The end product carries the unmistakable peaceful and reflective character that Green House Seeds highlights, validating the effort invested over a long, aromatic bloom.
