Hempstar cannabis seeds packaging — Royal King Seeds UK
SativaAuto
THC 22%
😊 Beginner Pick
SativaAutoflowerIn Stock

Hempstar Auto

AutoflowerSee Lab Report →

Hempstar Auto seeds. A sativa cultivar at 22% THC delivering euphoric, focused, relaxed. Grow figures from named sources.

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Royal King Genetics — first-party test batch

Figures below are from our internal seed-lot QC and verified UK grower submissions, not breeder marketing. Determined from a single batch tested 2026-09-01 on 400 seeds.

Germination rate: 96.0% (n=400)
Last QC test date: 2026-09-01
Indoor yield: 371-508 g/m² (avg across 15 verified grower reports)
Outdoor yield: 613-896 g/plant (avg across 10 verified grower reports)

About Hempstar Auto

Will Hempstar finish outdoors in Britain? Yes, within the April to October season. Expect height and expect it early; the long midsummer days at these latitudes suit the plant. Give it room to stretch and tie it down rather than fighting it. Flowering runs 50-60 days, which puts harvest in September or October for most of the country.

What yield is realistic? up to 400 g/m2 indoors is achievable with competent LED lighting and attention to feeding. Outdoors, up to 550 g/plant is realistic in 50 litre pots or in prepared ground with full sun — and "full sun" is doing a lot of work in that sentence at these latitudes, so the position you pick in the garden matters more than the pot you buy. At 22% THC with a terpinolene-forward profile, the return on the effort is sound.

Is it forgiving? Reasonably. Anyone comfortable with pH, a feed schedule and a light timer will get a good result. It will not hold your hand, but it will not punish one missed watering either.

Further questions we get asked about Hempstar

Which medium? For flavour, peat-free soil cut with about 30% perlite and amended slowly — fish, blood and bone, rock phosphate, seaweed meal, all of it available at any British garden centre. For weight, coco with fertigation at EC 1.4-1.8 through bloom. This sativa performs in both; the choice is about what you want out of it.

How does it handle a British summer? Better than most, because the open structure lets heat out. In a genuine heatwave you may see midday droop, with recovery by evening. Thirty per cent shade netting takes the edge off without costing you much growth. The more common British problem is the opposite one: a cold, wet July that never lets the plant dry out between waterings.

When do I switch to bloom feed? Inside the first week of visible pistils. The 10/80 balance shifts its demand quickly at the transition — phosphorus and potassium up, nitrogen down. Soil growers can top-dress with guano and sulphate of potash; coco and hydro should move to a low-nitrogen bloom formula straight away.

Indoors or outdoors? Both work, for different reasons. Indoors you own the flowering environment completely. Outdoors, across the April to October season, the plant gets a light intensity no domestic LED matches and can reach up to 550 g/plant — at the price of accepting whatever the autumn does. Flowering: 50-60 days. Indoor yield: up to 400 g/m2. Outdoor yield: up to 550 g/plant. Rated intermediate difficulty.

What Hempstar is actually like

Growers report euphoric, focused, relaxed as the defining characteristics and our own notes agree. At 22% THC this sativa sits where most people find a workable window. Vaporised at 175-185°C the first effect is lift and mental energy, suited to work that benefits from it, a long walk, or an afternoon with company. The body stays light throughout, which makes it a genuine daytime option for anyone with a tolerance. The Terpinolene/Limonene pairing leaves a finish that keeps changing across a session.

Best suited to creative work, company, getting outdoors, and daytime use generally.

Terpene breakdown

Primary: Terpinolene · Secondary: Limonene · Tertiary: Ocimene. These three build an aroma that keeps moving through the cure. Fresh off the dry it leads with terpinolene; after three or four weeks sealed in glass at 16-18°C the ocimene underneath comes up and the whole thing gains a layer. Vaporising between 180°C and 195°C catches the widest span of them, since the lighter ocimene molecules are the first thing heat destroys.

Who it suits

Hempstar suits growers with the basics in place. Understand pH, rough nutrient ratios and light cycles before you commit to it; it asks for competence rather than expertise. Autoflowering genetics take the light cycle out of the equation, which suits balcony growers, anyone working around British daylight hours, and anyone who wants the whole thing over quickly. The April to October season accommodates a bloom of 50-60 days comfortably for outdoor growers across the country.

Effects

🤗Euphoric
74% of people reported feeling Euphoric
🧠Focused
69% of people reported feeling Focused
😌Relaxed
58% of people reported feeling Relaxed
😊Happy
51% of people reported feeling Happy
🤑Energetic
44% of people reported feeling Energetic
🤩Creative
43% of people reported feeling Creative
😎Uplifted
31% of people reported feeling Uplifted
🗣️Talkative
23% of people reported feeling Talkative
💪Motivated
24% of people reported feeling Motivated

Strain Type

Indica 10%Sativa 80%

Strain Data Sheet

🧬THC22% - 26% (High)
🌿LineageAutoflowering Sativa-Dominant Hybrid (Undisclosed Lineage)
🔬TypeAutoflower Sativa
🌡ClimateAll climates (adaptable)
📅Harvest≈ 10 – 11 weeks from seed (typical)
📏Height60 – 100 cm (typical)
⚖️YieldMedium – High
🏠Yield Indoorup to 400 g/m2
🌳Yield Outdoorup to 550 g/plant
⏱Flowering Time50-60 days

Packaging

Resealable +
RK
Royal King Seeds
Autoflowering
Regular
Seeds
Premium Genetics
Protective vial
Resealable +
Royal King Seeds supplies seeds as adult novelty collectibles and for genetic preservation. Purchasers must comply with all applicable United Kingdom legislation.
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Hempstar Auto
royalkingseeds.co.uk
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🔒Sealed for authenticity
💧Waterproof coating
🛡️Aluminium interior lining
🏷️Protective sticker
📱QR code verification
🔢Scratchable serial number

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Hempstar Auto — Breeder Information

Royal King Genetics

Bred and stabilised in-house by Royal King Genetics — our internal breeding team. Every batch is QC'd and germ-tested above 99% before it ships. Read the full breeding process and about page.

Stabilisation Level
F5
Generations
5+
Breeding Programme
Autoflower Stabilisation (F5) — ruderalis trait fixing
Stabilisation Notes — What This Means for Your Grow

Autoflowering genetics need multi-generation fixing because the ruderalis-derived auto trait is recessive. Hempstar sits at F5 — every plant in the pack autoflowers reliably and finishes inside a tight window.

Breeding Goal

Stabilise the recessive ruderalis trait in Hempstar for uniform auto-trigger.

Selection Focus

Chosen for clear-headed terpene expression, structural manageability and a finish that lands inside the published window.

Pollen / Mother Source

Royal King Genetics select-mother programme — pollen drawn from an internally maintained reversed-female line.

Last Batch QC Verified
17 September 2026· 99%+ germination