When I gardened in Ireland, I never held much hope for a winter crop. I was too cold and too lazy to plant anything in the autumn, and when the freezing temperatures, hit I did not much mind what happened to the garden. Springtime would come and I'd start again.
Here it's different. If I'm careful, I can have stuff growing all winter that I couldn't grow in Ireland. But the question is, what will survive the frost and what won't? I'm looking froward to the Master Gardeners program to get a more definitive answer to that question.
Last year, I took precautions when we had the one and only frost warning of the year in December. I put bubble wrap over the lettuce, and they did really well surviving well into the hottest part of the summer before bolting. I'd heard that if peppers are protected from the frost they can be perennial, so I decided to wrap them in bubble wrap - some of them still had fruit on them. I also wrapped up the egg plants too, more as an experiment than anything.
they blossomed! It is still growing strong, and I'll move it, and three others like it, in Janurary.
Why is frost and low temperatures so damaging to some plants?
Well, when water freezes it swells, so if a plant freezes the water within the cells expands, bursting the cell walls. That is why when the plants thaw out, they just flop over.
The night before last the temperature dropped to 28F. The zucchini wasn't covered and it bit the dust.
website with great tips on frost protection (which you can read for yourself by clicking the link) that said to avoid covering with plastic - perhaps the bubble wrap was not as clever a plan as I had thought.
But the arugula was thriving.
But wait a minute - I forgot to re-cover that patch of lettuce last night - so how did it survive the low of 29F? After a garden fence clinic, (which usually occurs when I catch Al in his garden and quiz him on gardening matters over the fence) it transpires that, in fact, the lettuce is fairly frost resistant. This was totally unexpected. I turned to the internet for a second opinion and discovered that lettuce does survive a light frost. So, was all my nurturing in vain - those varieties that died were doomed - and covering those that were not susceptible, a waste of time?
Not necessarily - the BBC website suggests covering lettuce when a frost is likely. Admittedly, British frost and Californian frosts may drastically differ, but if it does get cold enough, damage will be done.
So, what makes a plant frost resistant? Apparently if a plant has a high content of salt in its cells, it is more frost resistant. This makes sense as adding salt to water lowers its freezing point. That why it is used on roads in the winter - not just to make them taste better for crazy people who may want to lick the road!
One thing I love about researching a question is that I tend to pick up lots of other useful titbits along the way. From the same website I read,
- Winter salads traditionally have a strong, robust flavour that can sometimes be a little bitter. If you find that your salad leaves are too bitter for your tastes, try blanching the leaves by covering the plants with an upturned flowerpot.
- Left like this for a few days before harvesting, the leaves will become paler and less bitter."
I'm going to try this with my arugula.
As for my kale forest - yummy - frost should sweeten the leaves! A silver lining in every cloud.