If you are like me, older and of Anglo-Saxon heritage, you probably would have been brought up with the notion of lettuces as a summer vegetable, Peter Rabbit in Mr. McGregor’s garden and all that. But while in England lettuces might be a summer vegetable, here in the Oz they are arguably more suited to spring, autumn and possibly, in mild coastal areas, Winter.
Lettuces are in fact good at handling cold conditions. While their leaves might look delicate, they are frost tolerant. Her in Ballarat two weeks ago we had a couple of late autumn frosts. While the lettuces in my garden were well and truly hit by frost by mid morning they looked like they had never been frosted. In contrast, a nearby pumpkin vine was well and truly clobbered.
So, does that mean they are a winter vegetable? Well, not really really. They will grow in Ballarat (cool mountainous region) in winter, and from what I hear they can do well in Victoria’s coastal climate. But here they tend to struggle in the winter, producing poor quality leaves that are often ravaged by slugs and snails. In winter I grow my lettuces (along with rocket and peas) in my greenhouse.
But come the mildly warm weather of spring and autumn lettuces thrive. It is easy to grow good quality sweet lettuce then.
However, when the hot summer weather hits, increasingly* I have found it harder to grow decent lettuces. They are quick to develop a bitter taste and to bolt. These days my strategy to counter this is to grow them under 50% shadecloth in summer. It works, but I still do not get as good lettuces as spring and autumn grown ones. More and more each summer I am reverting to Greek salads as cucumber and capsicum is much easier to grow in summer than lettuces.
Yes, I know there are lettuce varieties that have been bred for summer conditions, but I have found that even these are best grown under shadecloth in summer.
* I say “increasingly” because when I first started growing lettuces in Ballarat thirty years ago I was able to grow good lettuces in summer without covering them with shadecloth. While I accept the science of climate change, due to the complexity of the climate I am reluctant to attribute single events as signs of global warming. However, me no longer being able to grow good lettuces in full sunlight in summer may in fact be a small sign that the planet is warming up.
One of my lettuces that morning with its leaves covered in frost.
By ten that morning the same lettuce looked like in had never had a frost.
Just a few metres away my Jap pumpkin plant was well and truly hammered by the frost.
These days I grow my summer lettuces under 50% shadecloth. The bird netting is to stop sparrows picking at the leaves. They can do a lot of damage to lettuce and silverbeet leaves.