UK hardiness lookup
Oldham (OL) — RHS hardiness H6
Oldham, England · 148-day frost-free season
Frost dates and growing season for OL
| RHS hardiness rating | H6 |
|---|---|
| Average last spring frost | mid-May |
| Average first autumn frost | early October |
| Growing season length | ~148 days |
| Temperature range (C) | minimum -20 to -15 °C |
| Temperature range (F) | minimum -4 to 5 °F |
| USDA equivalent | Roughly USDA zone 6. |
UK frost dates come from Met Office regional climate averages (1991-2020). Frost pockets, valleys, and exposed elevation can shift Oldham-area gardens a full band colder than the regional figure. Coastal and urban gardens run a band warmer.
What grows at RHS H6 in Oldham
Cold-resistant plants that shrug off hard Scottish and northern winters. Suitable for upland and exposed gardens.The RHS rates plants — not regions — so check the rating on each plant's tag against this H6 baseline. Anything rated H6 or hardier (numerically higher) should overwinter reliably in a typical Oldham year.
- Picea, Pinus, Abies (conifers)
- Sorbus aucuparia (rowan)
- Birch (Betula pendula, B. utilis)
- Highland heathers (Calluna, Erica)
- Vaccinium (blueberries, bilberry)
- Rugosa roses
- Astrantia
- Lupins
- Cold-tolerant fruit — apple (Discovery, James Grieve), gooseberry, raspberry
- Vegetables — kale, cabbage, leeks, swede, parsnip, broad beans, early potatoes
When to plant in Oldham
Sowing, transplant, and harvest dates for the most common edible crops, calibrated to RHS H6 timing:
- When to plant tomatoes at RHS H6
- When to plant peppers at RHS H6
- When to plant basil at RHS H6
- When to plant garlic at RHS H6
- When to plant lettuce at RHS H6
- When to plant bush beans at RHS H6
- When to plant cucumbers at RHS H6
- When to plant summer squash at RHS H6
- When to plant peas at RHS H6
- When to plant carrots at RHS H6
For a one-shot starting point: tomatoes go outside from the mid-May window onwards; garlic goes in 4-6 weeks before early October; brassicas and salads can run on either side of the frost window with fleece in cold snaps.
Local microclimate notes
Postcode-area ratings are a baseline — your actual garden can sit a band warmer or colder. Urban heat-island effect lifts inner-city gardens; frost pockets at the bottom of slopes drop them. If you can record your own lowest winter temperature for a couple of seasons, that beats any regional average for planning.
For US gardeners reading UK references: RHS H6 is Roughly USDA zone 6. — see the matching USDA Zone 6 guide for the US-side planting calendar.
Source and methodology
Hardiness rating from the Royal Horticultural Society hardiness rating scale. Frost-date averages from Met Office UK climate averages (1991-2020), matched to the nearest representative regional station for postcode OL. Plant recommendations curated by the Growli editorial team. Last review 2026-05-19.
Other postcode areas in England
- EC1 — London (Clerkenwell) (RHS H4)
- EC2 — London (City) (RHS H4)
- WC1 — London (Bloomsbury) (RHS H4)
- WC2 — London (Covent Garden) (RHS H4)
- W1 — London (Mayfair / Soho) (RHS H4)
- SW1 — London (Westminster / Belgravia) (RHS H4)
- NW1 — London (Camden) (RHS H4)
- N1 — London (Islington) (RHS H4)
- E1 — London (Whitechapel) (RHS H4)
- SE1 — London (Southwark) (RHS H4)
- SE10 — London (Greenwich) (RHS H4)
- SW19 — London (Wimbledon) (RHS H4)
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