Fill your salad bowl with late winter lettuce

Lettuces are an essential crop for every garden – easy and quick to grow, and perfect for pots or small spaces. Plus there’s a huge range of varieties worth planting, so pack your plot, and fill your salad bowl, with frilly, oak leaf, hearting and loose-leaf lettuces in all shades of green and red!

When to sow: August to April in warmer areas; September to March in cooler areas

When to transplant: All year round in warmer areas; August to May in cooler area

Position: Full sun

Harvest: 10-12 weeks

Good for pots

Good for beginners

While we might think of lettuce in terms of refreshing summer salads, this leafy crop generally prefers cooler temperatures and tends to bolt to seed if it gets hot or dries out. Grow it in your vege beds as a shoulder season crop in spring and autumn, then confine it to containers in summer and winter, as you can keep them in the shade when it’s hot and move them into the most sheltered spot or even under cover when it gets cold.

Lettuce seed will germinate in relatively low temperatures (from about 10C) so you can sow direct or in trays from late winter to mid-autumn in temperate regions and early spring to early autumn in cooler ones. You can plant lettuce seedlings pretty much all year round in mild, temperate regions and from early spring to late autumn further south.

Lettuce seed is small and photodormant, which means it needs light to germinate, so sow thinly on the surface of the soil, or on the top of seed-raising mix if growing in trays, and just barely cover.

You can sow lettuce direct but it’s easier to protect them from slugs and snails if you start them in trays or jiffy pots for later transplant.

Keep the seed tray or newly planted seed just moist and you should see signs of germination in 7 days.

If your seedlings look crowded, it means you’ve been a bit heavy handed while sowing seeds. Worry not – just thin when 2-3 true leaves have formed. Or, leave them for another week, then eat the thinnings as microgreens.

If you are starting in trays, seedlings can be planted in the garden in about 3-4 weeks.

Give lettuces a spot in full sun from autumn to spring, but afternoon shade in the hottest part of the year. You can grow them on the shady side of a row of beans or a block of corn to keep them cool.

Prepare the spot with plenty of compost and sheep pellets as well as a dusting of lime.

Lettuces are shallow-rooted, so can dry quickly even in the ground. They will perform best if the soil stays consistently moist – mulch around this crop to keep the available water in the soil. A short period of drought stress, even if it does not cause the plant to bolt to seed, will mean the leaves start to taste bitter.

However, you don’t want to overwater either, as they also dislike wet feet and waterlogged soil.

And overhead watering (where you wet the leaves rather than the soil) will leave them prone to various fungal infections. If your soil is heavy and prone to becoming waterlogged, grow lettuces in pots to give them the drainage they need. Liquid feed weekly with worm tea or a liquid fertiliser at half strength.

Lettuces are a great crop for growing in pots, and if you opt for cut-and-come-again varieties, a couple of big pots is enough to provide you with salad greens for several months – just harvest leaf by leaf and plant a few new seedlings every three or so weeks.

Choose a decent sized pot (the smaller the pot, the faster it will dry out). Use a good potting mix that contains a well-balanced slow-release fertiliser and a moisture retaining agent that will help hold water in the soil.

Position your pot in a warm, sunny north-facing spot that’s out of the wind and, in places with hot summers, somewhere in afternoon shade over summer.

Irrigation is key to success with lettuces, so if you have a tendency to be slap dash about watering, invest in a self-watering pot with a built-in reservoir so the soil is less likely to dry right out.

Growing lettuces in pots means you can, with a bit of planning, keep growing lettuces all winter, although you’ll need to move the pot into a conservatory or tunnelhouse down south, as lettuces can’t take more than a tickle of frost.

Lettuces can loosely be divided into four groups.

Crisphead Batavian varieties such as ‘Iceberg’ and ‘Great Lakes’ and ‘Winter Triumph’ (a good choice in colder regions) have crisp leaves that wrap over each other to form a heart. Grown under the right conditions and at the right time of year, the leaves are super crisp and sweet. But they need more space than upright, cut-and-come-again varieties, and are slower to mature and more exacting in their cultural requirements – prone to rotting from the centre out in cold, wet conditions; bolting to seed if it’s hot and dry (although plant breeders have been working to develop varieties which will heart up reliably in summer); and will turn to mush immediately if faced with a frost.

Cos or romaine lettuces such as ‘Rouge d’Hiver’ and ‘Little Gem’ have upright elongated leaves that form a loose heart at the centre. The ribbed leaves are essential for Caesar salads and sturdy enough to fill with Thai- or Mexican-style mince mixes, plus you can harvest these varieties leaf by leaf.

For something a little different, ‘Silvia’ is a glamorous little red cos with a sweet taste and a buttery texture. As with most salad plants, the red colour is deeper in cooler weather, though it can handle a range of growing conditions. Pair it up with ‘Paris White Cos’ for a gorgeous colour combination both in the garden and on your plate.

Loose leaf lettuces such as ‘Lolla Rossa’, ‘Lollo Bionda’ and ‘Drunken Woman Fringed Head’, are also excellent as cut-and-come-again crops, with the soft leaves growing as rosettes rather than forming hearts. They are very fast to grow, maturing in less than two months (and you can start picking the baby leaves after just a month) and they come in a huge range of varieties, textures and colours to keep your salad bowl looking swish. ‘Green Salad Bowl’ produces a large rosette of wonderfully tender, bright green leaves; again, if you like playing with colours, pair it with ‘Red Salad Bowl’, an organic variety.

Finally, butterhead lettuces such as ‘Buttercrunch’ and ‘Summer Queen’ form an open but bunched rosette at the centre, surrounded by a fan of soft loose leaves. Butterhead lettuces probably cope best of all lettuces with warm weather, but still perform best as a shoulder season crop and need some shade during the hottest time of the day in summer. ‘Merveille des Quatre Saisons’ is an heirloom variety in this group. It has a great flavour, and well lives up to its name (which translates to Marvel of Four Seasons) by performing well throughout the growing seasons.

Another attractive heirloom is ‘Perella Rougette Montpellier’ which is green at the base, shading to cranberry-red on the outer edges of the leaves.

If you can’t decide, sow a packet of mixed lettuce seeds or a gourmet salad blend.

If your lettuce seeds aren’t germinating, the most likely culprit is the lack of light. Lettuce seed will also fail to strike if conditions get too hot (below 21C is preferable).

Once they are up, remember that pretty much everything finds lettuce delicious! Slugs, snails and birds will all make short work of this crop, especially when newly planted.

A cloche is a good way to protect them from pest predation, as well as offering some shelter from unexpected cold spells. (You’ll often see it suggested that beer traps are a good control for these gastropods or that slugs and snails won’t crawl over coffee grounds or broken up eggshells.

NZ Gardener trials found none of these pest control methods effective, but they didn’t seem to us to do any harm either so if they work for you, go ahead!)

Lettuces can also succumb to the attentions of the lettuce aphid (Nasonovia ribisnigri). Native to Europe, these pests are a nightmare for crisphead lettuces, as once they get to the heart of the lettuce, they can wreak havoc, sight unseen. If this is a problem, sow the aphid-resistant iceberg-type hybrid ‘Bug Off’.