Frost does not need to Bite!
The latter part of January is usually the coldest time of the year in this country. The temperature level usually fluctuates around the 0o degree level , often with a night frost just below freezing point and as the short day wears on, the mercury creeps up a few degrees plunging down again as the sun sets.
Gardeners on these shores have long learnt to cater for frost and know well that the dahlia tubers have to be lifted otherwise they will be a soggy mess at the end of the winter, the greenhouse has to be heated if we are growing tender plants, and it is not worth planting out any non frost hardy plants until all risks of frost has passed , which varies from mid April in the south West and around the coast line, and can be as late as mid May for Scotland and the central spine of England. In fact, coastal South western tips, can be spared of frost altogether in some years.
Different plants reactions to frost
It all depends on the constitution of the plant, some plants will die above ground but their roots can withstand frost and they will regrow next spring, some plants the frost will damage their roots as well, whilst others are frost hardy and will show no signs of distress at all.
Understanding RHS frost labelling codes
Talking of frost hardy plants, next time you buy a plant you might find some odd letters on them and you will thing they are part of a barcode but really they are the ‘new frost labelling codes’ set out by The RHS.
For generations, plants have been split into 4 categories to denote their ability to withstand frost. This has been illustrated with asterisks where * is the least hardy and **** is the most frost resilient plant. In 2013 the RHS changed the star system and split plants into 7 categories, an H7 plant is one totally frost hardy. A plant that will withstand an average winters in most parts of the U.K., which used to be indicated with two asterisks will now carry the symbol H4.
On the brighter side of things – lets look at some of the advantages of frost.
1] Although gardeners today like to see their plots as flat as a bowling green all the year round, when digging over in the autumn and winter there is no need to break up and smooth out the clods of earth, when the clods of earth thaw after a hard frost they will automatically break up into small particles.
2] The taste of parsnips and other root vegetables are said to get sweeter after a frost. Now I do not posses a Brix refractometer to measure my parsnips on the Brix scale of sweetness before and after the frost but I think there is some truth in it. I wonder if it would enhance the sweetness of the parsnips you buy all the year round, if you were to put them in the freezer for a few hours?
I also think that the frost adds an extra twist to my horseradish.
3] Frost is also said to kill many of the germs in the air. It will also kill the eggs of several of our garden enemies like slugs and snails.
4] I love the frost because it kills the weeds. There are always parts of my allotment that remain neglected towards the end of the summer due to lack of time. These usually get overgrown with annual weeds – when the first frost comes I can reclaim my plot as they die down. I also had a bramble playing havoc through the currants, now as the frost has killed of the weeds I can see the trees from the wood and I know where to dig it out!
This is all besides the wonderful picotee edge beloved by photographers that the frost carefully draws on the edge of evergreen leaves.
When I was a kid we still noticed jack frost on the window panes when we got out of bed, but now the first time you will greet him is when you go out to your car! So whilst you stand there de-icing and scraping your windscreen on a freezing cold morning, think about a few of the advantages of frost and it will make the job lighter and easier!
Good gardening ,
Boris Legarni .