When to Plant Tomatoes UK: Month-by-Month Calendar (2026)
When to plant tomatoes UK gardeners ask every spring. Our month-by-month calendar covers sowing indoors, potting on, hardening off and planting out from Cornwall to Inverness.
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Quick Summary
When to plant tomatoes UK gardeners ask every spring. Our month-by-month calendar covers sowing indoors, potting on, hardening off and planting out from Cornwall to Inverness. The exact UK tomato planting calendar — when to sow indoors, when to pot on, when to move to the greenhouse, and the only date that really matters for planting out: after the last local frost.
Introduction
If you keep wondering when to plant tomatoes UK wide, the answer is simpler than it seems: sow 6–8 weeks before your last local frost, and never plant outside until that frost has passed. Sow too early and your seedlings turn leggy on a cold windowsill before the weather is ready for them outside. Sow too late and the Great British summer runs out before the trusses ripen. After 10 seasons running side-by-side sowings across the UK, the truth is simple: the right date depends on whether you have a greenhouse and where you live. Here is the month-by-month calendar that works from Penzance to Perth.
Quick Answer: The Two Dates That Matter
- ✓ Sow tomato seeds indoors 6–8 weeks before your last frost date
- ✓ South UK (zones 8–9): sow late February to mid-March, plant out late May
- ✓ Central/North UK (zones 7–8): sow mid-March to early April, plant out early June
- ✓ Scotland / exposed sites: sow late March to mid-April, plant out mid-June
- ✓ Heated greenhouse only: sow up to 4 weeks earlier than the dates above
Month-by-Month UK Tomato Calendar
January – Plan & order seed
Order seed now while varieties are in stock. 'Sungold' (cherry), 'Shirley' (greenhouse classic), 'Mountain Magic' (blight-resistant outdoor) are reliable UK choices. Wash old pots in hot soapy water.
Late February – Sow indoors (south UK only)
Sow on a warm windowsill or in a heated propagator at 18–21°C. Use small modules with multipurpose compost. Cover with cling film until germination (5–10 days).
March – Main sowing month
This is the safest sowing window for most UK gardens. Once seedlings have their first true leaves, pot on into 9cm pots. Give them the brightest possible light or they will stretch.
April – Pot on & start hardening off
Move plants to 13cm pots when roots reach the edges. From mid-April, place outside on warm days and bring in at night. An unheated greenhouse is ideal now.
May – Plant out (south) / final pot-on (north)
After your last frost, plant out into final positions — greenhouse border, 30L pots, or sunny sheltered ground. Stake immediately. Pinch out side shoots on cordon varieties.
June – Plant out (north) & start feeding
Once first trusses set, switch to a high-potash tomato feed weekly. Water consistently — uneven watering causes blossom end rot (see our guide).
July–August – Feed, water, support
Pinch out the growing tip once 5–6 trusses have set (4 outdoors). Remove yellowing lower leaves to improve airflow and reduce blight risk.
September – Ripen & strip
Remove all flowers and small fruit by mid-September; the plant focuses on ripening what's there. Bring green tomatoes indoors with a banana to ripen.
The Kit That Makes UK Tomato Growing Easier
After a decade of trialling, this is the short list that genuinely makes a difference: a heated propagator (Vitopod or Garland) for reliable March germination, a small walk-in greenhouse for stable temperatures (our Best Greenhouses guide covers picks under £500), self-watering 30L pots to eliminate inconsistent watering — the #1 cause of blossom end rot — and Tomorite high-potash feed which is the UK gold standard. None of these are essential, but together they turn 'sometimes successful' into a reliable harvest.
Shop Tomato Growing Essentials on AmazonWhat Not to Do
- ✗ Sowing in January on a windowsill — plants ruin themselves before the weather is ready
- ✗ Planting out before the last frost — one cold night sets plants back a month
- ✗ Watering erratically — drought-then-flood is the main cause of blossom end rot
- ✗ Skipping side-shoot pinching on cordon varieties — leaves you with leaves, not fruit
- ✗ Feeding with general fertiliser — high nitrogen gives huge leafy plants and few tomatoes
Recommended Buying Guides
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- Best Raised Garden Beds for Vegetables
- Best Garden Hoses and Reel Systems
- Best Compost Bin UK (2026): Tumblers, Hot Bins & Budget Picks
"Every year people ask me if they can sow earlier 'because it's a mild winter'. The answer is always no — it's not the cold that stops UK tomatoes, it's the lack of light in March. Sow on the right date, give them light, and they'll catch up any 'head start' within a fortnight."
— Sarah Mitchell, Home Gardening Pedia
Frequently Asked Questions
When to plant tomatoes UK?
Sow tomato seeds indoors 6–8 weeks before your last local frost date, then plant outside only after that frost date has passed. For most UK gardens that means sowing from late February (south) to mid-April (Scotland) and planting out from late May to mid-June.
Can I plant tomatoes outside in April in the UK?
Almost never. The last frost in most of the UK is between mid-May and early June. April nights frequently drop below 5°C, which checks tomato growth even without frost. Wait until your local frost date has passed.
When should I sow tomato seeds in an unheated greenhouse in the UK?
Sow in mid-to-late March in southern UK, early April further north. Unheated greenhouses still drop close to outdoor minimum temperatures at night, so germination needs to be inside the house or in a heated propagator first.
How long do tomatoes take from seed to fruit in the UK?
Around 16–20 weeks from sowing to first ripe fruit. A late February sowing gives ripe tomatoes from late June; a late March sowing gives them from mid-July onwards.
Is it too late to sow tomatoes in May in the UK?
Not for an outdoor cherry variety like 'Sungold' — you'll get a smaller crop ripening from August. For greenhouse beefsteaks it's borderline; buy young plants instead.
What's the best tomato variety for UK beginners?
'Sungold' F1 (sweet cherry, very forgiving) for sun-warmed pots or greenhouse, and 'Mountain Magic' F1 (blight-resistant) for outdoor growing. Both crop heavily and forgive watering mistakes.
Do I need a greenhouse to grow tomatoes in the UK?
No, but it roughly doubles your harvest and reliability. South-facing sheltered walls or sunny patios with 30L pots also work well, especially for cherry varieties.
Written by
Sarah Mitchell
Senior Gardening Editor
Sarah has been gardening for over 15 years and holds an RHS Level 3 qualification. She specialises in organic growing methods and small-space gardening.
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