Crops › Lettuce (Cos/Romaine)
How to grow Lettuce (Cos/Romaine)
in the UK
Sow March to July, plant out August, harvest June to October. About 60 days from seed to plate.
Cos lettuce, or Romaine as some call it, is a proper cracking salad crop, you know. It's really easy to grow and always comes in handy for a fresh sarnie or a nice side salad. You can get a fair bit from a small space, which is always a bonus on the plot.
Sowing
You can get started with Cos lettuce from March right through to July, which is grand for a continuous supply. For an early start, sow a few seeds indoors in modules or trays, about 1cm deep. Once the danger of hard frost has passed, usually mid to late May up here in the North, you can start sowing direct outside, planting seeds about 15cm apart, or in rows, then thin them later. Like I say in the app, do a little bit every couple of weeks, and you'll always have some coming along.
Growing on
If you've started your seeds indoors, prick them out carefully into individual pots once they've got their first true leaves. Give them a good few weeks to harden off outside before planting them out on the plot, about 30cm apart. They don't need any special support, and lots of the smaller varieties do really well in pots or containers if you're short on space, like on a patio or balcony.
Looking after it
Cos lettuce likes a steady supply of water, especially when it's warm and dry, so keep an eye on them. A bit of general purpose feed won't go amiss if your soil's a bit tired, but it's not usually essential. Keep the weeds down around them, and that's pretty much it, to be honest. No fancy stuff needed.
What goes wrong
Slugs are probably your biggest headache with Cos lettuce, they love a good munch on those crisp leaves. Keep an eye out and pick them off if you can. Aphids can sometimes be a bother too, especially on the undersides of the leaves; a strong jet of water often sorts them out, or just squash them with your fingers if it's only a few.
Harvest
You're usually looking at about 60 days from sowing until your first harvest, so June right through to October is your window. You can either take the whole head, roots and all, or you can pick the outer leaves as you need them, letting the plant carry on producing for a bit longer. Best eaten fresh, though Cos does keep a bit better than the loose leaf types in the fridge for a few days.
I always try to plant a few onions or radishes nearby; seems to keep some of the nasties away, and it's a handy way to use the space.
Dates for your plot
Type the first half of your postcode and the plant-out advice shifts to your area's typical frost dates.
Varieties, and whether the club would grow them again
| Variety | Club verdict |
|---|---|
| Little Gem This is a cracking little mini cos, perfect for a quick snack or a side salad. It's an early crop and doesn't take up much room, so great for beginners or small gardens. | No club votes yet |
| Lobjoits Green Cos A proper traditional Cos lettuce, stood the test of time for a reason. Great flavour and reliable, if you're after a classic that does well outdoors. | No club votes yet |
| Parris Island If you're worried about your lettuce bolting in the summer heat, this one's a good bet. It handles the warmer weather better than most, so you can keep harvesting. | No club votes yet |
| Winter Density This hardy variety is perfect for extending your salad season well into the colder months. It's quite tough and can handle a bit of a chill, so you can get a late crop. | No club votes yet |
| Freckles A bit different this one, with lovely red speckles on the leaves, making your salads look proper fancy. It's a tasty addition and a bit of a talking point on the plate. | No club votes yet |
| Cos Antonella This maincrop Cos is known for its really sweet flavour, a real treat from the allotment. It produces good, solid heads that are a joy to eat. | No club votes yet |
| Valmaine A tall, dark green Cos that gives you a good amount of leaf from each plant. It's a reliable maincrop variety that's always welcome in the kitchen. | No club votes yet |
| Chartwell Ideal for growing in pots or smaller spaces, this one keeps a nice compact shape. It's also got a lovely sweet flavour, so you don't miss out on taste. | No club votes yet |
| Corsair If you've had trouble with diseases in the past, give Corsair a go, it's bred to resist them. This means less worry for you and a better chance of a cracking harvest. | No club votes yet |
| Lobjoits Cos Another cracking heritage variety, this Lobjoits Cos grows tall with lovely crisp leaves. It's a proper traditional choice for a tasty, crunchy salad. | No club votes yet |
| Pinokkio This mini Cos is super quick to mature, so you won't be waiting long for your first harvest. Perfect if you're keen for an early crop or just a bit impatient like me sometimes. | No club votes yet |
| Jericho A really good choice for those warmer summer months, as Jericho is known for being resistant to bolting. It means you get more time to harvest before it tries to go to seed. | No club votes yet |
| Paris White Cos This old French heritage variety produces tall, elegant heads of crisp lettuce. It's a real classic for a reason, offering great texture and taste. | No club votes yet |
| Rosalita Add a splash of colour to your salads with Rosalita, a lovely red Romaine lettuce. It's a heritage variety that's both crisp and visually appealing on the plate. | No club votes yet |
| Nymans If you're wanting fresh lettuce in the colder parts of the year, Nymans is a cracking option. It's bred to be tolerant to the cold, so you can often get a winter harvest. | No club votes yet |
Votes are members rating varieties in their Seed Tin, one vote per gardener. Tap a variety for the full page and where to buy.
Buy Lettuce (Cos/Romaine) seeds
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Cook the harvest
San choy bow is one of those dishes where the lettuce is absolutely load-bearing — it is the bowl, the crunch and the freshness all at once. The filling is a deeply savoury stir-fry of minced pork, water chestnuts and shiitake mushrooms seasoned with oyster sauce and a little sesame oil, then scooped straight into crisp cos cups at the table.
27 min · easyThe real thing — crisp cos lettuce in a punchy, creamy anchovy and Parmesan dressing with golden croutons fried in butter. This is the salad that made cos famous, and when you grow your own, you understand exactly why. Make it with leaves that were in the ground this morning and it is genuinely a different dish.
28 min · easyCrisp cos leaves make the perfect vessel for a fragrant, punchy filling of minced chicken with lemongrass, fish sauce, lime and chilli. This is fast, light and genuinely exciting to eat — the contrast of warm, herby filling against cold, crunchy lettuce is one of those combinations that never gets old. Great for a quick weeknight dinner or to share as a starter.
25 min · easyThe wedge salad is a genuine classic that deserves more respect than it gets. Thick, cold quarters of cos are drenched in a punchy, creamy blue cheese dressing and topped with crispy golden shallots, sweet cherry tomatoes and chives. The structure of cos means every bite has a proper crunch, and the lettuce stays cold and firm all the way through the salad.
30 min · easyWatch for, and grow alongside
Questions people ask
When do you sow Lettuce (Cos/Romaine) in the UK?
Sow Lettuce (Cos/Romaine) from March to July. Plant out August, after the last frost.
How long does Lettuce (Cos/Romaine) take from sowing to harvest?
Roughly 60 days, with the harvest June to October.
Which Lettuce (Cos/Romaine) varieties do gardeners grow again?
Club members rate every variety they grow. This page shows the grow-again votes for Little Gem, Lobjoits Green Cos, Parris Island, Winter Density and more.
Track your Lettuce (Cos/Romaine) from packet to plate
Sowing reminders and harvest forecasts for your own frost dates, the Seed Tin, Scan Centre for any label or packet, and the Potty Mouth Garden Club. Free to start.
Allotment keeper in the North East of England, the voice behind the Tony C Smith YouTube channel, and the gardener who built GrowMore CookMore. Club numbers on this page update as members log their plots. Last updated 3 September 2026.