The almost complete guide to growing lettuce
Written by Cab
Cab (with input from some other downsizers) tells you all about lettuce. How to grow it, and which sorts to grow.
How to Grow Lettuce
Of all of the food plants you can grow, none are more rewarding than lettuce. Sounds silly, I know, I mean, what is there to a lettuce? Isn’t it the boring green stuff that pads out a salad? Well, no. A well grown, fresh lettuce is the sweetest, tastiest, crunchiest melt in the mouth part of a meal. And best of all, its dead easy to grow too!
Okay, give me the condensed version!
First, buy some seeds. Get some compost, fill pots or seed trays with it, scatter the seed on thinly, and cover over with more compost. Water it, and wait. Soon enough (within a week or two) there will be plenty of seedlings there. Give them till there are three or four leaves, put them outside during the day to harden them off, and then plant them out in the soil. They like almost any kind of soil, as long as they don’t get too waterlogged or they don’t dry our entirely, and that’s it. You’ve grown your lettuce!
Hang on a minute, it isn’t that easy is it?
Yes, it is. It really is. Of course, there are things that can go wrong, but we’ll deal with them presently…
AHA! I knew it wasn’t that easy!
Well, no. Not quite, but pretty close. Lets go through this properly now.
Lettuce likes a rich soil, and it doesn’t want it too acid. So if your soil is very low pH then grow your lettuce somewhere limed recently. Lots of organic matter is good, as that holds on to moisture. Here we have the cultivated lettuces other main requirement, it likes the soil to stay damp. Never let it fully dry out if you can help it, it’ll soon wilt then it’ll go to seed.
Oddly enough for a crop you associate with summer salads, lettuce also doesn’t like it too hot. If the temperature stays above 20C, it’ll sulk and refuse to germinate. That leads to what many of us find to be an infuriating ‘lettuce gap’, in late summer, when you haven’t been able to persuade your lettuce to germinate.
Sow direct or in trays or pots first?
You can sow direct as soon as the ground has warmed up a bit. Actually, lettuce would prefer not to be moved, you’ll get your best specimens from sowing direct. While they like a bit of sunlight, they’re handy little plants in that they’ll put up with a bit of shade too.
One thing lettuce hates is being overcrowded. Sow quite thinly, and keep thinning them out as they grow (eat the sedlings in baby leaf salads) until they’re about 30cm apart.
If you prefer, sow the seeds in modules or in a seed tray, planting out when they’ve got three or four leaves. Harden off as you normally would, and plant them out. Try to get them out with as little root disturbance as you can, and you’ll get better lettuces for it. Never plant them deeper than the lower leaves.
How do I choose a good lettuce variety?
There are HUNDREDS of varieties of lettuce to pick from, so you’re spoiled for choice. Some favourites picked out by Downsizer members are listed at the bottom. But first you need to know what all the lettuce jargon is about.
You’ve got four basic types of lettuce.
Cos lettuce are upright, crispy, tallish and tasty. Fabulous, but they’re a bit slower to grow than some of the others.
Butterheads have soft hearts. They’re a doddle to grow, tasty, but not the crispest of creatures. Probably the most tolerant of poor conditions of all of the lettuces, and the easiest ones to form hearts.
Crispheads have the tighter heads associated with some of the harder supermarket lettuces (‘iceberg’). More resistant to bolting than butterheads, but a little pickier. Crispheads and butterheads are both refered to as ‘cabbage type&rsquo.
Loose leaf lettuces don’t form heads, which means you can pick off a few leaves here and there and leave the rest of the lettuce intact. They’re the easiest to grow, and they make ideal ‘cut and come again’ lettuces.
Now you know the basic language of lettuce, its all about selecting based on colour, shape and flavour. Pass the seed catalogue!
What goes wrong with lettuce then?
There is no such thing as a totally problem free crop. And things do go wrong with lettuces. Here’s my personal top 5 lettuce problems, and how to solve them:
(1) Slugs and snails.
Well, no way to avoid them entirely, But you can lessen their impact in a number of ways. Crumbled up eggshells or sharp sand around the lettuces can help. Old fashioned beer traps are good, as are the assorted organic tools at your disposal (copper stip barriers, nematodes, organic slug pellets, etc.
I personally find that planting spring onions in amongst them helps, but you have to plant the onion seeds first to let them grow a bit.
(2) Downy mildew, grey mold and other irritating forms of mankiness.
You get this sometimes if the weather is cool and wet. Often water gets into the heart and then you get a kind of rot setting in. It’s a good idea to water around the plants rather than on top when they’re hearting, and to sow a mix of varieties including some looseleaf ones (which are usually less prone) so that you’re not wiped out. But usually, at worst, this will only take a few of your lettuces.
Sodding starlings. Damned pigeons. They’ll strip out a whole row of lettuces in spring sometimes. Hang a few old CD’s on bits of string around your lettuce, or some strips of plastic, anything ‘fluttery’ to scare them away.
You might find the occasional lettuce starts wilting or just falls off from the stem. That’ll be cutworm. Little caterpillars, come out at night and eat the stem away. Hoe around the plants, pick up and squish any caterpillars you find.
(5) Aphids and other crawling or flying gits.
Yep, you get them on lettuce like you do on everything else. Soapy water spray does for them usually, unless the infestation gets really bad. The worst I’ve seen was a lettuce completely covered in blackfly, themselves being farmed by ants. I don’t mind admitting that I dug that one out and drowned the beasties, and I sprayed the lettuces around them to save the rest of the crop. That’s a rarity though, for the most part you can get away without such drastic measures.
Lettuce seeds are cheap. Most varieties seem to come in never ending seed packs with thousands of seeds in them, and if you get the occasional gardening mag in summer you’ll probably end up with freebies too. But that doesn’t make saving your own seeds a bad thing to do, especially if you’re fortunate enough to get one of the rare varieties (such as any of the varieties from the HDRA heritage vegetables library) or even just if you’re looking to save a few pennies.
As luck would have it, saving seeds from lettuce is a doddle. My standard method is to let one variety go to seed at a time, it’ll throw up a seed stalk that you can ignore, and unless theres another variety close by in bloom too you just have to wait till the seed heads get fluffy, rub them off the stems and allow them to dry before storing till spring. Or, if you’re even lazier, leave them on and wait till baby lettuce plants start springing up all over that bit of garden. I can’t quite put my finger on why, but self seeded lettuce plants seem more hardy and better able to survive through winter than any I’ve sown myself, and they don’t lose any flavour or sweetness for being allowed to grow all on their own.
If you want to ensure that you get only the variety you’re after then get a bit of string and a paper bag, and tie the bag over the seed flower head as it forms. Lettuce is self fertile, so although you’ll miss out on the chance of crossing (so you’ll not get much of what they call ‘hybrid vigour’), you’ll still get true seed. This is more appropriate if you’re saving multiple varieties or if you’re growing on an allotment site where there may be other lettuce plants in flower.
Lettuce Growing Calendar
February- Make early sowings of lettuce indoors, under glass. Most strains of lettuce will do okay at this time of year; recommended varieties include amorina, little gem and webs wonderful.
March- In warmer areas, make protected sowings outdoors (cold frame or cloche). Once the soil has warmed up, most varieties will germinate well. Loose head types are best suited to early outdoor sowings.
April-May- If it looks like the risk of a frost has passed, and your soil is becoming warm, direct sowings outside are possible. Make sure that seedlings are spaced out sufficiently and well watered. Plant earlier seedlings out when its safe to do so, or keep them in pots or trays as ‘cut and come again’ lettuce. Now is the time to start successional (every couple of week) sowings to ensure a continual supply.
June-August- In warmer areas, sooner or later you’ll enter the ‘twilight zone’, when those few lettuce seeds that germinate seem rather wilty and unwell. That’s all to do with the seeds struggling to get going at high summer temperatures. Counter that by either refrigerating seeds for three days prior to planting, or keep your seed trays in cool, shady spots out of the sun.
September-October- As temperatures start to fall, its time to make sowings of winter hardy lettuces. ‘Valdor’ and ‘winter king’ are both good, but you’ll find that many varieties of lettuce do surprisingly well all through winter, if you give them a bit of protection. So if you’ve got a cool greenhouse, a sunny window ledge or a bit of cold frame space, you can continue growing these lettuces (or at least keep the ones you’ve grown sweet and tasty) well into the dark, dark, gloomy month of January
November-January- Now its all a bit gloomy, so unless you can keep fresh sowings of lettuce reasonably warm it just isn’t worth sowing them. If you have any lettuce left outside, get some cover on them; fleece will help, a cold frame is better. If you’re feeling brave, and you’ve got a good, sheltered spot in the garden, you might get away with over-wintering them uncovered. In a mild winter I’ve managed this with the variety ‘freckles’ in a warm corner of my garden in Cambridge.
Varieties, as reccomended by Downsizer contributors...
"Freckles is a superb lettuce, being a soft leaved, cos types taking its name from the red flecks all over its light green leaves. Sweet flavoured, easy growing and slow to bolt, good for lettuce heads or cut and come again. The only down side is that if it gets really heavy rain it can tend to rot in the middle, but thats quite a common problem with cos type lettuces."
"Amorina is a vibrant red and extremely curly variety, and I'd say its one of the most useful lollo rosso type lettuces I've grown. Slow bolting, never seems to suffer mildew or rotting, and its also somewhat cold tolerant. And best of all, if you sow one tray early in the season you can plant seedlings out over a long period, they form nice, compact heads when you give them the space to do so. Also less bitter than some other lollo rossos."
"Great lakes is a popular American variety, and I grow it because its both tasty and versatile. I sow it thickly, taking the thinnings out for use as baby leaves, leaving only a few to produce big, round, crisp green heads. Dependable, really, a nice change from Webbs wonderful."
"loose leaf lettuce "revolution"-Sensational deep red to almost black colour, good size, vigour, slow to bolt and good flavour. Can be grown under glass or outside."
"lettuce "Habana"- The darkest leafed butterhead with pale yellow hearts."
"Standard lettuce "Lakeland" boring to some but reliable and tasty"
"I love good old "Little Gem", small and sweet and tasty, and because of its' heart it doesn't tend to get full of bugs or dirt!"
"Sherwood - a romaine lookalike that appears to be ignored by slugs. Grows quickly, doesn't mind being transplanted if you sowed too thickly and is very slow to bolt. Sweet, crunchy and very tasty leaves. Definitely my desert island lettuce."
"Romana which is a classic Romaine lettuce used for making Caesar salads."
"Green Salad Bowl, pretty ruffled leaves."
"Webbs Wonderful, haven't grown this before and haven't cut one yet for tasting. But the idea is that these will give a nice closed head of lettuce."
"All Year Round, a butterhead type of lettuce, good for growing through colder months too. "
"Celtuce - Gorgeous stuff. Basically a chinese lettuce, its a bit more like a wild lettuce and the leaves have a very slight bitter touch to them, rather reminiscent of radiccio or chicory. The leaves picked young are great in a salad, but as it grows up and flowers it throws up a thick flower stalk which you can slice up and stir fry. A nice little multi-purpose vegetable, I've got three of them sitting in amongst some lettuces. Whereas the lettuces are all a trifle snailed (on that patch it would be sherwood, freckles and northern queen) the celtuce is untouched."