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Outdoor Cannabis Seeds — Weather-Tough Genetics for UK Conditions

These strains are handpicked for outdoor resilience across the UK's diverse climate zones — from the milder, longer season of the south coast to the short, cool, wet run in Scotland and upland Wales. Outdoor growing harnesses free sunlight and open space to produce the largest individual plants possible, with top genetics yielding well over a kilogram per plant in ideal conditions. Browse our outdoor-optimised collection for weather-resistant, pest-tolerant genetics that finish on schedule in your region.

All strains in this collection are bred & stabilised in-house by Royal King Genetics

603 strains available

Per-Plant Yield250–1000+ g
Harvest WindowMar–May (Aus)
Light SourceNatural Sunlight
Ideal ForLarge Plants & Open Space

Best Strains For Outdoor Growing catalogue at a glance

Our best strains for outdoor growing collection currently holds 603 strains in active inventory with verified THC content ranging from 1% at the low end to 33% at the high end (median 21%).

Strains
603
THC range
1-33%
Median THC
21%
Auto / Photo
0/602
  • Feminised photoperiod: 602 strains (100% of the catalogue) — single-flip genetics with the largest single-plant yields.
  • Sativa-dominant: 186 — cerebral effects, taller plants, Limonene-Pinene-Terpinolene profiles common.
  • Balanced hybrid: 417 — mixed indica/sativa lineage, ranges from 60/40 to 50/50 splits depending on phenotype.
  • Alphabetical lineup starts with: $100 OG, 13 Dawgs, 24k Gold — see the full grid below for filters, lab data and grower reports.

Best Strains For Outdoor Growing — Browse All Strains

Qualities of a Reliable Outdoor Strain

Outdoor genetics need to handle what nature delivers: wind, rain, temperature swings, pests, and mould pressure. The best outdoor strains carry natural resistance to botrytis and powdery mildew, tolerate temperature variation without stalling, and finish flowering within your local season window. In the UK, the primary outdoor growing calendar runs from late April to October, and the decisive part is the wet end of it. Tropical and subtropical sativas thrive in the warm north, while fast-finishing indicas and autoflowers are the reliable option in cooler southern states.

Outdoor Strains Matched to UK Regions

Southern England (mildest, longest season): the widest choice, and the one region where a longer photoperiod is a fair outdoor bet — Sour Diesel, Jack Herer and taller sativas belong indoors here. The Midlands and Wales (temperate): Northern Lights, White Widow, Blue Dream, and mould-resistant hybrids. SA and WA (hot, dry): nearly any strain performs with adequate irrigation — ideal conditions for sativas and landraces. Scotland and northern England (cool, short season): autoflowers and fast-finishing indicas such as Critical Mass beat the early frosts. Across all regions, autoflowers guarantee a finished harvest before cold weather arrives.

Picking Outdoor Seeds for Your UK Postcode

Season length is the primary filter. Count the warm weeks available between your last spring frost and first autumn chill — that is your outdoor window. Photoperiod strains must complete flowering within that window, so check listed bloom durations carefully. Autoflowers only need ten to twelve weeks regardless, making them viable almost everywhere. Factor in local humidity: wet autumn conditions demand mould-resistant genetics or early-finishing strains. Shorter, bushier plants attract less attention than towering sativas — a practical consideration for discreet outdoor cultivation.

Why Grow Outdoors

Sunlight is the most powerful and spectrally complete light source on the planet — no artificial fixture fully replicates it. Outdoor plants can grow to massive proportions and yield accordingly. There is no electricity bill, and natural air movement keeps plants healthy without fans. The trade-offs: a single annual harvest window (unless using autoflowers), exposure to weather and pests, and less environmental control than an indoor setup. Many serious growers maintain both indoor and outdoor operations to capture the strengths of each.

Outdoor Growing Tips for the UK Climate

Start seeds indoors under a grow light in September and harden off seedlings before transplanting outdoors in October, once frost risk has passed. Position plants in a north-facing spot for maximum solar exposure (south-facing receives the most light in the UK). Prepare the ground with compost, worm castings, and amendments ahead of planting. Fabric pots or raised beds improve root aeration and drainage. Protect young transplants from possums, rabbits, and slugs. Monitor for mould from late February onward as humidity tends to rise. Harvest when trichomes are cloudy — do not delay if rain is approaching. Our regional outdoor guides detail the specifics for each state.

Frequently Asked Questions

When is the right time to plant cannabis outdoors in the UK?
Start seeds indoors during September. Transplant outdoors after the last frost date, which falls in October across most of the country. Autoflowers can be planted later in the season and still finish in time. Harvest typically runs from early September to mid-October depending on strain and how far north you are.
Which outdoor strain performs best in the UK overall?
Blue Dream, Northern Lights, and Sour Diesel are consistently top-rated outdoor performers. Blue Dream offers balanced effects and natural mould resistance. Northern Lights finishes early for southern growers. Sour Diesel excels in warm climates with massive outdoor yields.
How much does an outdoor plant produce?
Outdoor harvest weight ranges widely: 250 grams to over a kilogram per plant depending on strain, climate, soil, and technique. Under ideal indoor conditions, experienced growers regularly surpass 800 grams per plant with yield-bred genetics.
Can I grow outdoors in Scotland or northern England?
Yes — choose fast-finishing strains or autoflowers. Northern Lights, Critical Mass, and auto varieties complete their cycle before autumn cold sets in. Starting seeds indoors and transplanting after frost extends the effective growing window.
How do I prevent mould on outdoor plants?
Start with mould-resistant genetics. Space plants well for airflow. Shake water off buds after rain. In humid climates, favour strains with open bud structures over dense indica types. Harvest promptly if conditions deteriorate rather than risking the crop.
How much water do outdoor plants need in the UK?
During peak summer heat, outdoor plants in the ground need 4–12 litres per day depending on size and soil type. Container plants require even more frequent watering. Mulching the soil surface conserves moisture significantly. Water early morning or late evening to minimise evaporation losses.

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