This lettuce, sometimes sold under the name ‘Romaine’, is easily spotted by its compact, tall, ribbed leaves. It is the robust nature of its leaves that make it so good for salad as the leaves will not wilt when a dressing is added.
You can either grow cos lettuce from seed, or plugs are readily available at garden centres. Have to admit, I go for the latter. Once planted they mature in about two months and are slower to bolt, i.e. go to seed, than other lettuces.
They are easy to grow outside here and actually are supposed to taste better than ones grown in tunnel houses. All salad crops need some protection from the Wakatipu sun, so site your lettuces where they get shade at some point during the day.
Although the darker outer leaves are actually the most nutritious and sometimes used by restaurants, they are no way as delicate and tasty as the paler, inner leaves and can have a bitter taste, or taste of absolutely nothing.
Whole heads of cos lettuce will store for seven to 10 days in a sealed bag or container but only wash the leaves when required as storing washed leaves can encourage bacterial growth.
Good for the waistline, the cos lettuce has a high water content but not a lot of calories and is a better source of Vitamin C than many other lettuces.
And a new tip I have just discovered. Apples and cos lettuce are not good companions as the ethylene gas the apples give off turns the lettuce leaves brown.