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Greenhouse or outdoor tomatoes in the UK

Updated: October 2026

You are deciding where the plants will stand, and the place changes the season more than the brand does. Greenhouse or outdoor tomatoes is a location choice. Under glass you usually get an earlier, heavier crop and you dodge more blight. Outdoors can still crop in a warm, sunny, sheltered spot, and it fails more often in a wet summer. Several packets here never say which they suit. None of them is a blight-resistant variety the RHS names. The [tomato seeds comparison](/hub/herb-seeds/tomato-seeds) holds the eleven packets. Listings were read on amazon.co.uk on 15 October 2026. A qualifying purchase can earn a commission at no extra cost to you.

You are deciding where the plants will stand, and the place changes the season more than the brand does. Greenhouse or outdoor tomatoes is a location choice.

Our top picks

Just Seed Just Seed Sungold F1 tomato seeds

Best overall

Just Seed Just Seed Sungold F1 tomato seeds
9.5/10about £3.65
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Just Seed JustSeed Moneymaker tomato seeds

Best value

Just Seed JustSeed Moneymaker tomato seeds
9.3/10about £2.75
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Meldon Seeds Meldon Moneymaker tomato seeds

Alternative

Meldon Seeds Meldon Moneymaker tomato seeds
9.3/10about £2.95
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On this page
  1. 1.What the greenhouse changes
  2. 2.Outdoors, with a condition
  3. 3.Blight is the outdoor risk
  4. 4.What these listings say about place
  5. 5.12°C on a packet and 16°C on the RHS

What the greenhouse changes

The RHS says greenhouse crops are usually earlier and larger than outdoor ones. You sow a little earlier, you plant while nights are still sharp outside, and the fruit has more weeks before autumn. That is a longer season, not a promise of flavour and not a disease-free room. If you cannot ventilate, a sheltered outdoor spot can ripen cleaner fruit than a sealed tunnel, even though the RHS still expects the outdoor crop to be later and lighter.

Outdoors, with a condition

Outdoor plants need warmth, sun and shelter. They are frost-tender. A heat-holding courtyard meets that sooner than an exposed bed. May is a usual month in these sources, not a date for the north of Scotland. A north-facing fence does not become sheltered because the packet was cheap. The later sowing window exists so outdoor plants are not huge and pot-bound through April. If you already sowed in early February, you will be housing them until that move. The steps for the wait are on how to sow tomato seeds.
Just Seed Just Seed Sungold F1 tomato seeds

Testsieger

Just Seed Just Seed Sungold F1 tomato seeds
9.5/10about £3.65
View offer

Blight is the outdoor risk

The varieties that did well at Wisley in 2021 are 'Crimson Crush' and 'Mountain Magic'. They are not in this set. Do not read Moneymaker, Ailsa Craig, Sungold, Black Krim or San Marzano as those cultivars. This page does not repeat a disinfectant dose. Use the product label. What a wet summer does to the crop is on tomato blight in a wet summer.

What these listings say about place

Meldon's Moneymaker and Ailsa Craig are the clearest. Both say a greenhouse, a polytunnel, grow-bags, pots, or a sheltered outdoor spot. That matches the RHS condition of shelter. It is not a promise that a wet August will spare the fruit. Both are indeterminate, about 1.5 metres and about 1 metre on the listings, so an outdoor plant still needs a stake. Habit clashes are on the buying guide. Black Cherry and San Marzano carry an outdoor attribute. Black Cherry never answers the indoor question. San Marzano's height says 20 inches while the bullets say indeterminate, so “outdoor” there is not a finished plan. The kit, Mar Azul and Montserrat say move plants out only above 12°C. JustSeed Moneymaker, Sungold F1, Gardener's Delight and Black Krim do not state a place. Black Krim's reviews include a London outdoor pot and comments that the fruit rots outside. They do not turn a silent listing into an outdoor variety. If the page is silent, use the RHS condition, not one review.

12°C on a packet and 16°C on the RHS

Do not treat 12°C on Mar Azul, Montserrat or the kit as the RHS planting rule. Keep sowing temperature separate. Meldon's 18–21°C, the kit's 22–28°C and the RHS figure of about 18°C are about sprouting seed, not about the night you plant out. Choose the greenhouse when you want the earlier crop and a lower blight risk, and when you can ventilate. Choose outdoors only for a warm sheltered spot, and do not buy these packets as blight-resistant varieties.

Common questions

Are tomatoes better in a greenhouse in the UK?
Usually, if better means earlier and a heavier crop, which is the RHS comparison. A greenhouse that overheats still gives tough skins and blotchy ripening unless you shade and ventilate. Glass makes blight less likely. It does not make blight impossible, because vents and doors are openings.
Can I grow them outside without a greenhouse?
Yes, in a warm, sunny, sheltered place. They are frost-tender, so the move is after frost, usually in May on Gardeners' World's calendar, once you have hardened them off. The crop is typically later and smaller than under glass. A cheap packet does not create shelter you do not have.
When do I plant them out?
After hardening off, when frost is over. Gardeners' World says usually in May. The RHS says early summer, once temperatures stay reliably above 16°C. Listings that say above 12°C are using their own threshold. Pick one rule and keep to it, including the couple of weeks of hardening off.
Will outdoor tomatoes get blight?
They are at serious risk in warm, wet weather from early summer. The pathogen is Phytophthora infestans. Greenhouse plants are less likely to be infected and can still be infected. Do not compost infected haulms. Green fruit on a badly hit plant may already be infected. The RHS suggests using it at once, for example in chutney, rather than storing it to ripen.
Are any seeds in this set the blight-resistant ones the RHS names?
No. The RHS cites 'Crimson Crush' and 'Mountain Magic' from Wisley in 2021. Those names are not among these eleven packets. Moneymaker, Ailsa Craig, Sungold, Black Krim and San Marzano are not sold here as those cultivars. A familiar salad name is not a resistance claim.
Should I grow potatoes in the next bed?
Gardeners' World says not to plant potatoes close to tomatoes, because they share blight. A gap the width of a path is still close if the foliage meets in a wet July. If you grow both, separate them, and do not compost the remains of a plant that already has the disease.

Related pages

Which tomato seed packet fits you

Tomato seeds

Tomato seeds UK: six checks before you buy a packet

F1 or heirloom tomato seeds: which packet should you buy

How to sow tomato seeds in the UK: month, heat, depth

Sources

Public UK sources named for this comparison. Listings read on 15 October 2026.

  1. RHS, How to grow tomatoes (retrieved October 2026)
  2. RHS, Tomato blight (retrieved October 2026)
  3. Gardeners' World, How to grow tomatoes (23 May 2025) (retrieved October 2026)
  4. Seed Marketing Regulations 2011, Schedule 3 (retrieved October 2026)
  5. GOV.UK, Plant breeders' rights (retrieved October 2026)
  6. amazon.co.uk listings for the eleven packets, read 15 October 2026 (retrieved 15 October 2026)