Lettuce Seeds in Ireland
Lettuce is the closest thing Ireland has to a year round crop from seed. Our summers are rarely hot enough to bolt it the way they do further south, and a winter hardy variety under a cloche will keep cutting when nothing else in the garden is moving. The catch is slugs, and this page is honest about how much of Irish lettuce growing is really slug management.
Sowing and harvest calendar for Ireland
Months shaded below are the reliable windows for Irish conditions.
Quick facts
- Botanical name
- Lactuca sativa
- Difficulty
- Easy, good first crop
- Hardiness
- Hardy, takes Irish frost
- In Ireland
- Cloche or fleece helps
- Germination
- 6 to 12 days at 10 to 20C
- Sowing depth
- 6mm
- Spacing
- 25cm apart, 30cm between rows
- Position
- Full sun
- Containers
- Grows well in pots
- Sowing to harvest
- 6 to 14 weeks
- Harvest
- May to November
Sowing depth and spacing
Drawn to scale from the figures in this guide.
How deep, seen from the side
How far apart, seen from above
The best lettuce varieties for Irish gardens
Picked for how they perform in a cool, damp, short summer rather than for catalogue photos.
Tom Thumb
Heirloom / Mini butterhead
The best lettuce for a container, a small plot or a first sowing with children, and it is ready faster than anything else.
Growing notes and stockistsWebb's Wonderful
Heirloom / Crisphead, iceberg type
The crunch of a shop bought iceberg with actual flavour, if you can give it space, water and a slug plan.
Growing notes and stockistsSalad Bowl
AGMOpen pollinated / Loose leaf, cut and come again
The most forgiving lettuce there is, and the one that turns a single sowing into six weeks of picking rather than ten days.
Growing notes and stockistsWinter Density
AGMOpen pollinated / Cos, winter hardy
The variety that puts lettuce on the table in December and January, and the reason an August sowing is worth remembering.
Growing notes and stockistsHow to sow lettuce seeds
Lettuce seed is small and germinates better with light reaching it, so sow shallow. Six millimetres of fine compost, or a bare dusting of vermiculite, is plenty. Buried deeper than a centimetre a good proportion of the packet will simply sit there.
Modules beat a drill in the ground for most Irish gardens. Fill a module tray with peat free seed compost, water it before you sow rather than after, drop two or three seeds into each cell, cover lightly and keep the tray somewhere between 10 and 20C. Thin to the strongest seedling once the seed leaves have opened flat. A module raised plant goes out at four to five weeks with a proper root ball and enough leaf to survive a bad night, which is the whole argument for the extra tray.
Direct sowing works from late March to August into a bed raked to a fine tilth. Sow thinly along a shallow drill and thin in two stages. Water the drill before sowing in dry weather, because lettuce that has to wait for rain to germinate often germinates unevenly.
Whichever method you use, sow a little and often. Six modules every fortnight will feed a household better than a full packet sown in one go, which produces a fortnight of salad and then a row of bolting plants.
Growing on in Irish conditions
Plant out into ground that has had some compost worked in, firming each plant just enough that a tug on a leaf does not lift it. Space hearting varieties 25 to 30cm apart and loose leaf types 15cm. It looks generous when they go in, and it is the difference between clean plants and rot in a wet September.
Water is the main job. Lettuce is over ninety percent water and roots shallowly, so it feels dry weather long before deeper rooted crops do. In a dry spell give the bed a proper soaking twice a week rather than a daily sprinkle, and aim the water at the soil, not over the leaves, which keeps the crowns dry and gives botrytis less to work with.
Summer sowings are the ones that need thought. Site the tray in shade, sow in the evening, and if you are sowing into a polytunnel in July accept that the tunnel is the worst place for germination even though it is the best place for growing on. Move trays out to a shaded spot outdoors until they have come up.
From October onwards, growth is limited by daylight rather than temperature. A cloche, a low tunnel of fleece over hoops or a corner of a polytunnel bed will not make winter lettuce grow fast, but it keeps the leaves out of the rain, which is what actually kills them here.
Harvesting
Hearting types are cut whole, at the base, with a knife. Cut early in the morning while the leaves are still turgid and they will keep for a week in the fridge; cut on a warm afternoon and they flop before they reach the kitchen.
Loose leaf varieties are picked, not cut. Take the outer leaves from each plant and leave the growing point untouched, and the same plants will keep supplying for four to six weeks. If you would rather cut the whole rosette, leave a 3cm stump and it will regrow at least once, though the second flush is smaller.
Do not wash lettuce until you need it. A dry head in a bag in the fridge keeps far longer than a washed one, which starts to break down almost immediately.
Watch for the centre of a hearting plant beginning to lift and firm up into a point. That is the plant getting ready to bolt, and it is the signal to eat it this week rather than next.
What goes wrong with lettuces in Ireland
Slugs and snails
Signs: Young plants grazed to the stump overnight, ragged holes in outer leaves, silvery trails across the bed in the morning.
What to do: This is the Irish lettuce problem and it is worth planning around rather than reacting to. Raise plants in modules and plant out at four to five weeks rather than direct sowing, because a seedling with four true leaves survives damage that kills a cotyledon. Clear the slug shelter first: boards, weedy edges, long grass beside the bed. Go out with a torch an hour after dark two or three nights running after planting, which removes more slugs than anything sold in a bottle. Ferric phosphate pellets are approved for organic growing and work, but only if the shelter is cleared too.
Seed that never comes up in summer
Signs: A June, July or August sowing where almost nothing germinates, while the same packet worked in April.
What to do: Lettuce seed enters thermodormancy above roughly 25C and simply refuses. Sow summer batches in the coolest shady spot you have, water the compost before sowing rather than after, and never leave a module tray in direct sun. Sowing in the evening so the seed takes up water overnight while it is cool makes a genuine difference. Refrigerating the sown tray for 24 hours also works if you are stuck.
Bolting
Signs: The plant stretches upwards, the centre pushes into a spike, and the leaves turn bitter and milky.
What to do: Less of an issue here than seed packets suggest, but it happens in a hot dry spell or when a plant is checked by drought. Keep water steady, never let a container dry out, and pick before perfection rather than after. Cos and loose leaf types stand longer than butterheads. Once a plant has bolted the bitterness does not reverse, so compost it and cut the next sowing.
Grey mould and rot under cover
Signs: Brown slimy patches at the base of overwintering plants, a fuzzy grey growth, whole hearts collapsing after a wet week.
What to do: Botrytis is the reason winter lettuce fails in an Irish tunnel, not cold. Water in the morning and only at the roots, ventilate on every dry day even in January, space winter plants wider than summer ones, and pull off yellowing lower leaves before they rot into the crown.
Aphids in the heart
Signs: Colonies of green or grey aphids deep in the folded leaves, sticky residue, distorted new growth.
What to do: Under cover aphids build up fast because the predators are outside. Ventilate, squash colonies early, and rinse cut heads well. Outdoors, hoverflies and ladybirds usually deal with them by midsummer if you have not sprayed. Loose leaf varieties are easier to check and wash than tight hearting types.
Tip burn on the inner leaves
Signs: A brown papery scorch along the margins of the young central leaves, mostly on crisphead types.
What to do: A calcium delivery problem caused by irregular watering rather than a shortage in the soil, exactly as with blossom end rot in tomatoes. Water consistently and generously, especially for iceberg types in containers, and avoid heavy nitrogen feeding that pushes soft growth faster than the plant can support.
Where to buy lettuce seeds in Ireland
Irish suppliers that stock this, so postage stays domestic and seed arrives in time to sow. These are plain links, not paid placements.
Order online
- Brown Envelope Seeds Irish Organic seed saved in West Cork, so already adapted to Irish conditions Grows and saves its own certified organic seed in West Cork, so the varieties are already adapted to Irish conditions. Visit Brown Envelope Seeds , Co. Cork
- Quickcrop Irish Sowing and harvest months listed on every packet, ships nationwide Ballymote based, lists sowing and harvest months per product and ships across Ireland. Visit Quickcrop , Co. Sligo
- Seedaholic Irish Heirloom lettuces with unusually detailed packet notes, from Co. Galway Family run in Clonbur since 2005, deep heirloom range with detailed growing notes on every packet. Visit Seedaholic , Co. Galway
Garden centres and mixed retailers
- The Organic Centre Irish Organic salad seed from Rossinver, Co. Leitrim Registered Irish charity at Rossinver with a 19 acre demonstration garden behind the seed catalogue. Visit The Organic Centre , Co. Leitrim
- Mr Middleton Irish The familiar named varieties, posted from Dublin Mail order arm of a long established Mary Street shop, carries the familiar named varieties the organic specialists skip. Visit Mr Middleton , Co. Dublin
- Woodie's Cheapest packets and the only nationwide click and collect Dublin headquartered chain, part of Grafton Group. Cheapest per packet and the only nationwide click and collect option. Visit Woodie's
Common questions
When should I sow lettuce seeds in Ireland?
There is a sowing for almost every month. February and early March sowings go in modules under cover for planting out in April. From late March to August you can sow outdoors directly, though the coldest and wettest weeks are best skipped. August and early September sowings of a winter hardy variety are the ones most Irish gardeners miss, and they are the sowings that give you leaves in December and January. If you want a single date to start with, mid-April outdoors is close to foolproof.
Can I grow lettuce through the Irish winter?
Yes, with the right variety and some cover. Winter Density, Arctic King and Valdor were bred for it and will sit through frost, though they grow very slowly from November to February because of light levels rather than cold. Sow in late August or early September, plant under a cloche, a low tunnel or into a polytunnel bed by October, and cut leaves rather than whole heads. The plants effectively pause midwinter and then put on a burst of growth in February. Expect slower regrowth and be sparing with each cut.
How do I stop slugs eating my lettuce in Ireland?
Accept that you will not eliminate them and aim to get the plants past the vulnerable stage instead. Raise seedlings in modules where slugs cannot reach them and plant out sturdy four to five week old plants. Clear boards, pots, weedy edges and long grass from around the bed, because that is where slugs shelter by day. Night hunting with a torch for the first few nights after planting is the single most effective thing you can do. Ferric phosphate pellets are approved for organic use and work well; beer traps catch a few but also attract slugs in. Copper tape and eggshells do very little in wet Irish weather.
How often should I sow lettuce for a continuous supply?
Every two to three weeks through the season, and only a short row or half a dozen modules each time. A batch of hearting lettuce is at its best for about ten days and then starts to go over, so one big sowing gives you a glut followed by nothing. Loose leaf varieties stretch the window considerably because you pick outer leaves over four to six weeks from the same plant, so a mix of one hearting sowing and one loose leaf sowing each month suits most households.
Can I grow lettuce in pots or a window box?
Very well, and it is often the best answer in a slug heavy garden. Lettuce is shallow rooted, so a 15cm deep container is enough, and a window box on a wall is far harder for slugs to reach than a bed. Loose leaf types and mini butterheads such as Tom Thumb suit containers best. The one rule is never let the compost dry out, because a checked lettuce in a pot bolts or turns bitter quickly. Peat free multipurpose compost is fine; you do not need anything special.
Do I need to thin lettuce seedlings?
Yes, for direct sown rows, and it is worth doing in two stages. Thin first to about 10cm when the seedlings have two true leaves, then again to 25cm for hearting types or 15cm for loose leaf once you can see which plants are strongest. Both sets of thinnings are perfectly good salad. Crowded lettuce does not simply grow smaller, it grows soft and damp at the base and rots, which in a damp climate matters more than the competition for light.