How To Grow Arjan’s Ultra Haze 1 from Seed to Harvest

Arjan’s Ultra Haze #1 by Green House Seeds Co. is a tall, award-winning, near-pure sativa for the dedicated haze lover. Built from Neville’s Haze x Cambodian x Laos genetics, it is a feminized photoperiod plant with a 21-22% THC level, a complex flavor of fruit, wood, spice, and earth, and an introspective, focused, calming effect. It grows big with a long 11-12 week bloom and rewards patience with huge yields, which is why it is a classic connoisseur strain. 

This is a feminized photoperiod strain, not an autoflower, so it flowers when you shorten the light cycle and gives you full control over veg length, training, and cloning. The figures below are the breeder’s values; check your own pack for the exact numbers. 

Recommended Strains

Arjan's Ultra Haze #1

	THC	21% - 22% (Medium)
	Lineage	Neville's Haze x Cambodian x Laos
	Type	Feminized
	Height	6.73 ft | 2.05 m
	Yield Outdoor	40.57 oz/plant | 1150 g/plant
	Flowering Time	11 - 12 weeks
	Phenotype	20% Indica / 80% Sativa
	Effects	Relaxed, Focused, Calming
	Flavors	Fruity, Woody, Spicy, Earthy

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3 Seeds - $325 Seeds - $45 Add to cart

Arjan's Ultra Haze #2

	THC	22% - 23% (Medium)
	Lineage	Neville's Haze x Mango Haze x Laos
	Type	Feminized
	Height	6.56 ft | 2 m
	Yield Outdoor	38.8 oz/plant | 1100 g/plant
	Flowering Time	12 - 13 weeks
	Phenotype	20% Indica / 80% Sativa
	Effects	Uplifted, Powerful, Talkative, Sedative
	Flavors	Fruity, Woody, Spicy

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3 Seeds - $325 Seeds - $45 Add to cart

Arjan’s Ultra Haze 1 Grow Info 

These are Green House’s published figures for Arjan’s Ultra Haze #1 at Growlantis. When you need an exact THC percentage, height, or yield, check the specification on your own Arjan’s Ultra Haze #1 seed pack. 

What Makes Arjan’s Ultra Haze 1 Worth Growing 

Arjan’s Ultra Haze #1 is a true haze connoisseur’s strain. Its Neville’s Haze, Cambodian, and Laos lineage gives it a complex, layered aroma of fruit, wood, spice, and earth, and a clear, introspective, focused high at a solid 21-22% THC. It is an award-winning cultivar with a reputation for quality that rewards those who appreciate classic sativa effects. 

Its other draw is sheer production. Outdoors in a warm climate, a single plant can return around 1150 g, a huge yield that reflects its towering size and vigor. It is a long-flowering, tall plant that asks for space, a long season, and patience, but for experienced growers it delivers both elite haze quality and serious weight. 

Is Arjan’s Ultra Haze 1 Indica or Sativa? 

Arjan’s Ultra Haze #1 is a near-pure sativa, listed at 80% sativa and 20% indica, from its Neville’s Haze, Cambodian, and Laos heritage. 

That strongly sativa makeup defines the grow and the effect. The high is introspective, focused, and calming in a clear-headed, cerebral way rather than sedative. The plant is tall, stretchy, and vigorous with the long flowering time typical of pure hazes, so it demands vertical space, a warm climate, and real patience. 

Flowering Time vs Full Grow Time 

Because Arjan’s Ultra Haze #1 is a photoperiod strain, these two numbers are separate, and the distinction is critical with such a long-flowering haze. 

• Flowering time: 11-12 weeks. This is the bloom stage, which starts only when you switch the lights to 12/12 indoors (or when days shorten outdoors). It is one of the longer blooms you will find, so plan carefully. 

• Full grow time (seed to harvest): flowering plus however long you veg. Because of the long bloom, indoors a typical grow runs around 5 to 6 months from seed. 

The practical point: keep veg short, because this haze stretches enormously in flower. Outdoors, its long bloom means a late finish, often around late October into November in warm climates. 

Does Arjan’s Ultra Haze 1 Need a 12/12 Light Cycle? 

Yes. Arjan’s Ultra Haze #1 is a photoperiod strain, so indoors it needs a 12/12 light cycle (12 hours on, 12 hours off) to start and maintain flowering. 

With a plant this tall and stretchy, flip timing is critical. Keep veg short and flip to 12/12 while the plant is still small, because it can easily double or triple in height during the long flowering stretch. Outdoors, shortening late-summer days trigger flowering, though its long bloom means a very late harvest. 

Arjan’s Ultra Haze 1 Grow Timeline, Week by Week 

Treat this as a development pattern, not a fixed schedule, and keep veg short to control the extreme stretch. 

• Weeks 1-2: germination and seedling. The taproot and first true leaves establish. Keep humidity up and feeding minimal. 

• Weeks 2-4: a short vegetative stage. Keep veg brief under 18/6 because of the huge flowering stretch. Start training early. 

• Week 0 of flower: the flip. Switch to 12/12 while the plant is still small. 

• Weeks 1-5 of flower: major stretch and bud set. Expect dramatic vertical growth before flower sites form. 

• Weeks 6-11 of flower: bud development. Long, airy haze colas slowly fill out and the complex spicy aroma builds. 

• Weeks 11-12 of flower: ripening and harvest. Judge by trichomes; this long bloom demands patience. 

Choosing Your Setup: Space, Light and Pots 

Arjan’s Ultra Haze #1 is tall, around 2.05 m, with an extreme flowering stretch, so vertical space and height control are the defining challenges. Keep veg short, flip early, and use a SCROG net and heavy low stress training to manage its size indoors. Many growers find it better suited to a greenhouse or outdoors. 

Give it strong light to fill out its long colas through the extended bloom. A full-spectrum LED at 30-40 watts per square foot over the flowering canopy helps. Add a good inline exhaust fan and a carbon filter for the complex, spicy aroma. 

For pots, 5 gallon or larger containers suit this big plant, scaled up outdoors. Fabric pots improve root airflow and help prevent overwatering. 

Germinating and Raising Seedlings 

The paper towel method is the simple, reliable start. Soak the seeds for 12-24 hours, then place them between damp paper towels on a covered plate, kept dark and warm at 70-85°F (21-29°C). A taproot usually appears within two to three days. 

When the taproot reaches about 1-2 cm, plant it root-down a knuckle deep in a light mix and keep the surface moist until the seedling emerges. Hold off on nutrients at this stage. New to growing? Our beginner growing guides cover germination step by step. 

The Vegetative Stage, Topping and Training 

With this haze, veg strategy is all about controlling height. Keep the vegetative stage short under 18/6, because this near-pure sativa stretches enormously once you flip. A long veg gives you an unmanageable plant indoors. 

Topping early is strongly recommended to create multiple colas and a wider, lower profile rather than one giant central spire. Combine it with aggressive low stress training and a SCROG net to keep the canopy flat and under control. This is also the stage to take clones: cut from a healthy plant in veg to preserve a phenotype you like, since photoperiods clone reliably. Train hard and early, and finish before the flip. 

Feeding and Watering Arjan’s Ultra Haze 1 

Feed to the stage. Use a nitrogen-forward base through the short veg, then move to a bloom formula higher in phosphorus and potassium once you flip to 12/12 and buds form. A big plant on a long bloom needs steady feeding, but pure hazes can be sensitive, so start moderate and increase based on how the plant responds. 

Water by root-zone moisture, not a timetable. Let the top inch or two of medium dry between waterings, then water thoroughly until a little drains. A large plant drinks heavily over the long bloom, so monitor it closely. Fabric pots and this water-to-weight habit keep the roots healthy and prevent overwatering. 

Flowering and Knowing When to Harvest 

Once you flip to 12/12, expect a dramatic stretch, then long, airy haze colas slowly fill out over the long 11-12 week bloom. The complex fruity, woody, spicy aroma develops, so keep air moving and run a carbon filter indoors. 

Patience is essential with a bloom this long. Let ripeness, not the calendar, decide the harvest: check the trichomes under a loupe and cut when most are cloudy with a few turning amber. After harvest, hang the branches in the dark at about 60°F (15-16°C) and 55-60% humidity for 7-14 days, then cure in sealed jars, burping daily for the first couple of weeks to protect the complex flavor. 

Growing Indoors vs Outdoors 

Indoors, Arjan’s Ultra Haze #1 is a challenge for experienced growers. Its height and long bloom demand a short veg, an early flip, heavy training, and a SCROG net, plus the patience to run 11-12 weeks of flower. 

Outdoors or in a greenhouse is where it belongs. In a warm climate with a long season, it reaches its full towering size and returns a huge yield of around 1150 g per plant, usually finishing very late, around late October into November. Give it full sun, deep rich soil, and plenty of room. 

How Tall and How Much? Height and Yield 

Height is a defining factor with this haze. It reaches around 2.05 m and stretches dramatically in flower, so indoors you must keep veg short, flip early, and train hard. Outdoors, give it full vertical freedom. 

On yield it is a huge producer outdoors, listed at around 1150 g per plant in a warm, long-season climate. Strong light, a well-managed canopy, a long season, and patience through the extended bloom are what turn that enormous potential into real weight of classic haze flower. 

Best US Climates for Arjan’s Ultra Haze 1 

Arjan’s Ultra Haze #1 is built for a warm climate with a long growing season, since its 11-12 week bloom pushes the outdoor finish very late. Growers in California, the Southwest, and the warmest Southern states can give it the heat and season it needs to reach full size and ripen outdoors. 

In shorter-season or cooler states, it is best grown indoors or in a greenhouse where you control the environment and can commit to the long bloom and height management. In the humid Southeast, keep strong airflow through its big, airy canopy. For more options, browse our full how-to-grow guide library. 

Common Problems When Growing Arjan’s Ultra Haze 1 

A few predictable, haze-specific issues are easy to head off. 

Extreme flowering stretch 

This is the biggest challenge. Keep veg short, flip early, top, and train hard to a net, or the plant will outgrow an indoor space entirely. 

Impatience with the very long bloom 

At 11-12 weeks it tests patience. Harvesting early sacrifices the classic haze effect and yield, so read the trichomes and wait for a mature finish. 

Short or cool seasons 

Its long bloom needs a warm, long season outdoors. In cooler regions it may not ripen outdoors, so grow it indoors or in a greenhouse instead. 

Airy sativa buds and rot risk 

Long haze colas can trap moisture in humid conditions. Keep strong airflow through the canopy and humidity moderate in late flower. 

Making the Most of Your Harvest 

Do not waste the trim. The resinous sugar leaves make good bubble hash, dry sift, or rosin that keeps the complex, spicy haze character. The stems, roots, and fan leaves compost well and feed your next grow. 

Is Arjan’s Ultra Haze 1 Right for You? 

If you are an experienced grower who loves classic haze and has the space, heat, and patience for a long bloom, yes. Its award-winning quality, complex flavor, and huge outdoor yield make it deeply rewarding. If you have limited height, a short season, or want a fast, easy plant, it is not the right choice. Browse our full how-to-grow guide library for more.

Frequently Asked Questions 

Is Arjan’s Ultra Haze 1 indica or sativa? 

Arjan’s Ultra Haze #1 is a near-pure sativa, listed at 80% sativa and 20% indica, from its Neville’s Haze, Cambodian, and Laos heritage. The high is introspective, focused, and calming in a clear, cerebral way rather than sedative. The plant is tall, stretchy, and vigorous with the long bloom typical of pure hazes. 

How long does Arjan’s Ultra Haze 1 take to flower? 

Arjan’s Ultra Haze #1 flowers in 11 to 12 weeks, one of the longer blooms you will find, typical of pure hazes. With a necessarily short veg, total seed-to-harvest time runs around 5 to 6 months indoors. Outdoors it finishes very late, around late October into November. Judge the finish by trichome maturity, not the calendar. 

Does Arjan’s Ultra Haze 1 need a 12/12 light cycle? 

Yes. It is a photoperiod strain, so indoors it needs a 12/12 light cycle to flower. With a plant this tall and stretchy, flip timing is critical: keep veg short and flip while it is still small, since it can double or triple in height during the long flowering stretch. Outdoors, shortening late-summer days trigger flowering. 

How much does Arjan’s Ultra Haze 1 yield? 

Arjan’s Ultra Haze #1 is a huge outdoor producer, listed at around 1150 g per plant in a warm, long-season climate, reflecting its towering size. Strong light, a short veg, heavy training to control height, a long season, and patience through the 11-12 week bloom are what turn that enormous potential into real weight. 

How tall does Arjan’s Ultra Haze 1 grow? 

Arjan’s Ultra Haze #1 is tall, reaching around 2.05 m, and it stretches dramatically in flower. Indoors this makes height management the defining task: keep veg short, flip to 12/12 early, top the plant, and train hard to a SCROG net. For many growers it is better suited to a greenhouse or outdoors where it has room. 

How strong is Arjan’s Ultra Haze 1? 

Arjan’s Ultra Haze #1 is potent at 21 to 22% THC, listed as medium. The effect is introspective, focused, and calming in a clear, cerebral way, a classic haze high rather than a sedative one. Its award-winning pedigree and complex flavor of fruit, wood, spice, and earth make it a genuine connoisseur’s sativa. 

What does Arjan’s Ultra Haze 1 taste like? 

Arjan’s Ultra Haze #1 has a complex flavor of fruit, wood, spice, and earth from its Neville’s Haze lineage. To protect those terpenes, run a carbon filter in flower, dry slowly at around 60°F with moderate humidity, and cure in sealed jars, burping daily for two weeks. A careful cure keeps the layered haze character full.