As daylight starts to dwindle from the June solstice onwards, thoughts are more of growing and harvesting than of sowing. Yet the later summer months, August and September, alongside those of early autumn, are still bright enough for growing a handful of hardy crops.
Lettuces, quick-maturing and tolerant of cool temperatures, are a good example. Certain varieties can be started now for a late autumn or early winter harvest. Others, like the well-known “Arctic King” or the cos variety “Winter Density”, can be sown in September and October for lush spring pickings.
I’m gardening in a ruthlessly small urban space. I have about fifteen pots, a metre by half-a-metre raised bed, and a mini greenhouse. Most of that space is now standing bare. So in this blog I want to share some advice about the lettuces I’ll be starting from seed. The hope is for a harvest before, and soon after, the year’s end…one that also makes use of all those leftover plastic pots!
What & When to Plant Lettuce
There are four main types of lettuce: cos, butterhead, loose-leaf, and crisphead. Cos and crispheads – the most popular variety in the UK is “iceberg lettuce” – both form tight hearts and take longer to mature. The butterheads, so named for their waxy leaves, and loose-leaf varieties tend to be quicker growing and can often be harvested in as little as ten weeks after sowing.
I’ll be growing cold-weather tolerant butterhead and loose-leaf varieties for a late autumn crop (October through November), and winter varieties of crisphead lettuce for an early to mid-winter one (December through February). Other slower growing varieties, like Robinson’s, Winter Gem, and aforementioned Arctic King, can be planted now and will mature in time for spring.
Lettuce for a late autumn crop (Oct-Dec): Any cold-resistant, fast-growing butterhead or loose-leaf. I’ll be trying Tom Thumb, All the Year Round, Marvel of Four Seasons and Valdor. I’m also going to see how Lollo Rosso fares.
Lettuce for early/mid winter crop (Jan-Mar): Crisphead varieties able to withstand cold temperatures, like Robinson, Match and Winter Purslane.
Lettuce for an early spring crop: Slow-growing and cold-hardy: Arctic King, Winter Gem, Winter Density.
Lettuce in cloches
Because I’m mainly growing outdoors, I’m a little wary of the colder weather that can set in from September onwards. My simple home-made cloches are comprised of bamboo canes and polythene sheeting held together by twist ties.
I think a lot of people hear the word “cloche” and immediately think of an overly-expensive contraption. Making one at home is a simple task. Otherwise, you can buy cheap “tunnels” online. Equally, I’ll be adding some netting to protect against birds and caterpillars. Monty Don recommends it…so it must be right!
Growing Lettuce Indoors
If you’re growing indoors, on a north, west or east-facing window sill, then you obviously don’t need to worry about either cold or pests. Make sure to water regularly, as the need is greater indoors.
Getting the Soil Just Right
They like it moist, fairly nutrient-rich (but not overly so), and non-acid. I’m using the old soil in my pots so I’ll be adding about a third of fresh compost, a few handfuls of vermiculite and perlite to assist with moisture retention and drainage, and a half-strength slow-release fish, bone and blood-meal fertilizer. After about eight weeks (six weeks is normally given), if you haven’t added any fertilizer, you will need to start a feeding regimen. Remember that, because of the waning light, growth will be slower. Use a slightly more dilute version than usual.
Composted manure, because it’s high in nitrogen, which is responsible for stimulating foliage growth, is also a good alternative to compost. A high nitrogen medium will be an obvious benefit to any plant grown for their leaves.
All of that said, if you can only get your hands on is a bag of multi-purpose compost that will do the job. I’ve grown lots of plants, including lettuces, using the simple bagged compost from B&Q. My main worry is about is about not having the roots stand in cold water, as the roots can freeze.
Lettuces with tight hearts (the crisphead and cos types) should be harvested in one go by pulling. Loose-leaf and butterhead varieties can be harvested with a “cut and come” approach, in which leaves are snipped off about half an inch above the soil level, from which new growth emerges. With later-season growing, I’ve found it’s not always a good idea to take this approach, because light levels won’t stimulate much additional growth. I find it better to let the whole plant grow as big as possible then harvest in one go.
You can find other fantastic salad crops to pair with your lettuce at our salad hub page, alongside our best how-to guides and variety recommendations.