XJ-13 cannabis seeds packaging — Royal King Seeds UK
Hybrid
THC 23%
🎨 Creative
HybridFeminisedIn Stock

XJ-13 Feminised

Feminised PhotoperiodSee Lab Report →

Grow XJ-13 Feminised in the UK. Hybrid genetics at 23% THC, known for energetic, happy, relaxed effects.

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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 2026-09-19 on 250 seeds.

Germination rate: 99.1% (n=250)
Last QC test date: 2026-09-19
Indoor yield: 404-552 g/m² (avg across 16 verified grower reports)
Outdoor yield: 650-962 g/plant (avg across 3 verified grower reports)

About XJ-13 Feminised

Will XJ-13 finish outdoors in Britain? Yes, within the April to October season. The balanced genetics cope with what British weather does from one week to the next, from damp air on the west coast to the drier run of counties in the east. Flowering runs 9-10 weeks, which puts harvest in September or October for most of the country.

What yield is realistic? Up to 650 gr./m2 indoors is achievable with competent LED lighting and attention to feeding. Outdoors, Up to 800 gr./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 23% THC with a limonene-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 XJ-13

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 hybrid performs in both; the choice is about what you want out of it.

How does it handle a British summer? Well enough, on hybrid vigour. Keep the root zone under 28°C with mulch or pale pots, and do not transplant into a heatwave. 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 50/50 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 800 gr./plant — at the price of accepting whatever the autumn does. Flowering: 9-10 weeks. Indoor yield: Up to 650 gr./m2. Outdoor yield: Up to 800 gr./plant. Plant height: over 185 cm tall if left untrained. Rated intermediate difficulty.

Flavour, aroma and effect

XJ-13 arrives in stages. The first draw at 23% THC brings a bright citrus edge that lifts off the palate immediately. The energetic, happy, relaxed character follows within minutes, as a head and body effect at once. The mind stays clear while the muscles let go by degrees, which is what makes it adaptable — a small dose carries an afternoon, a larger one turns into an evening. The caryophyllene underneath adds a warmth that keeps the whole thing anchored.

Terpene breakdown

Primary: Limonene · Secondary: Caryophyllene · Tertiary: Linalool. This combination turns up often in cultivars that win things, and it is usually the one growers comment on when a jar is opened for the first time after curing. Limonene anchors the aroma, caryophyllene occupies the middle, and linalool sits behind both — which is the part that separates this strain from others sharing its primary terpene.

Who it suits

Who does well with XJ-13? Indoor growers who want the timeline under their own control. Outdoor growers who want to choose when flowering starts. Anyone with the room and the patience to veg it properly before flipping. Difficulty is rated intermediate, which means a moderate learning curve that rewards attention without demanding a laboratory.

Effects

🤑Energetic
71% of people reported feeling Energetic
😊Happy
65% of people reported feeling Happy
😌Relaxed
58% of people reported feeling Relaxed
🤩Creative
56% of people reported feeling Creative
🤗Euphoric
47% of people reported feeling Euphoric
😎Uplifted
38% of people reported feeling Uplifted
🤤Hungry
34% of people reported feeling Hungry
😴Sleepy
31% of people reported feeling Sleepy
😆Giggly
24% of people reported feeling Giggly

Strain Type

Indica 50%Sativa 50%

Strain Data Sheet

🧬THC23% - 27% (High)
🌿LineageJack Herer × G13 Haze
🔬TypeFeminised Hybrid
🌡ClimateTemperate, adaptable
📅HarvestLate Sept – Oct, UK outdoor (typical)
📏Heightover 185 cm tall if left untrained
⚖️YieldTypical for type
🏠Yield IndoorUp to 650 gr./m2
🌳Yield OutdoorUp to 800 gr./plant
⏱Flowering Time9-10 weeks

Packaging

Resealable +
RK
Royal King Seeds
Photoperiod
Feminised Premium
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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XJ-13 Feminised
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🛡️Aluminium interior lining
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XJ-13 Feminised — 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
F3
Generations
3+
Breeding Programme
F3 Refinement Programme — three-generation selection
Stabilisation Notes — What This Means for Your Grow

XJ-13 runs through our F3 programme. Most of the pack expresses the target pack-to-pack uniformity cleanly; the F3-to-F4 cycle is where we close out the last remaining off-types.

Breeding Goal

Cull off-type phenos in XJ-13 at F3 to lock the cross profile.

Selection Focus

Chosen for terpene profile, vigour, structure and finish-time consistency.

Pollen / Mother Source

Royal King Genetics in-house breeder room — pollen taken from a generation-tracked sibling-male line.

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