Frozen Broccoli and Maple Syrup
What does frozen broccolli and Maple Syrup have in common? Genetics.
I’ve been waiting patiently all winter to prepare my small space garden for Spring, then along comes Siberian weather conditions so it hasn’t quite worked out as planned, and we now have a second wave of snow and frost in mid-March to contend with.
In Febuary I bought a plastic greenhouse thinking it would at least provide a sheltered space for my seed trays. My “greenhouse” is not the super cheap variety, and it does have a bit more in the way of durability and strength in the fabric at least, as well as some guide ropes to hold it in place. However, it was not quite designed with Siberian storms in mind. With winds and snow driving in from the east to blanket our little seaside town in subzero temperatures and road blocking snowdrifts.
I know that most seeds require a period of cold and dormancy as they prepare to germinate, but this was a bit much to ask of any living thing expecting no more than a chilled morning mist and light frosts with warming spring sunshine. I’m still not sure how this story will end because the weather and spring shoots across the country are only just beginning to recover.
An unexpected saving grace perhaps was that it was so cold, the compost within the individual seed tray compartments had also frozen, and although scattered to the floor as the greenhouse broke it’s moorings, the pods remaind mostly intact. All I had to do was pop them back into the compartments before they began to thaw. Which I did. The tiny shoot and seed survival is yet to be determined though.
So, post rescue mission, now inside, in the warm with a good book I got to wondering about plants with an apparent natural coping mechanism to the cold and freezing temperatures. The Purple Sprouting Broccoli not only looks good in the snow, it’s still growing, supplying the dinner table with delicious purple florrets and greens for the pigeons. The broadbeans are full of potential and the garlic spears are rising. The Kale is also quite the survivor.
How do plants survive cold seasonal temperatures?
Seasonal winter temperatures in the UK are typically between -1°C (30°F) to -12°C (10°F) depending on location of course. They can create ground frosts which may severely effect the roots and stems of plants, or an air frost which although bitterly cold for the foliage and flowers is unlikely to be fatal, especially if the ground is mulched. (Mine is not)
So how do plants cope with all that winter has to offer? I believe it’s important to understand at least the basics of plant chemistry, not least because we now have to cope with unseasonal shifts in weather temperatures caused by global warming. So a bit of online horticultural biology research had a few answers which I shall happily share with you here.
Trees in winter and Maple Syrup
In autumn and winter the leaves on most deciduous trees change colour and fall off, (a process called abscission. The leaves change colour due to a loss of chlorophyl, the natural chemical responsible for turning leaves green and an essential element in photosynthesis and in producing oxygen for all living things on Earth. This is a natural transistion which also helps the trees prepare for the diminishing daylight hours and subsequent reduction in the amount of photosynthesis.
Nutrients from the leaves are drained into the stems and branches to provide a store of energy to keep the tree alive until spring when the temperatures rise and daylight hours lengthen triggering new growth for, you guessed it, photosynthasis.
But that’s not all, by shedding the leaves, the tree is effectively protecting itself from the stress that would be caused from the cells in the leaves being frozen. The cells within branches and the trunk of the tree are protected from freezing temperatures by replacing the water from inside the cell with a liquid high in sugar becoming more resistant to freezing. A prime example is the Maple tree sap used to make Maple Syrup. Clever Stuff.
Evergreens and other non-decidiouse trees such as fir trees have a different technique to protect themselves against the frost. They replace the water in their cells with their own antifreeze compound and retain the needle like leaves. This creates insulating layers from the cold. They also tend to grow in a shape which makes it easy to shed the snow if it gets too heavy. Even cleverer.
So how do smaller plants like broccoli survive freezing temperatures? To cut a long biology lesson short, it’s all to do with a combination of carbohidrates, CO2, ethenol and the amount of light a plant gets, and a bunch of long sciency words. All resulting in the reduction of the amount of compounds and fluids that are effected by freezing temperatures. It’s all about natural chemistry.
So, what does frozen broccolli and Maple Syrup have in common?
Trees and broccoli etc have over millenia developed genetically coded instructions on how to survive natural seasonal temperature changes. Global warming however is forcing changes in agricultural behavour and natural environments around the world, simply because the evolution of the natural world just can’t keep up with consumerism. Even though some of the industrial and political leaders of today choose to ignore it. Perhaps one day they’ll begin to change their attitude when the Myple Syrup turns sour.
Back in the small space garden
So lets talk about the plants that are naturally engineered to survive the normal temperatures of winter months, and even a few unseasonal changes especially those on the vedge plot.
My top 5 winter hardy vegetables
Broadbeans, make sure you get the overwinterng kind. I’m growing the Sutton variety which can be sown throughout Spring and early summer as well.
Garlic, all kinds including Elephant Garlic bulbs can be planted from October through to January
Broccoli, sown in May, my favourite is the Purple Sprouting kind but other varieties can be planted throughout the year.
Cabbage, Planted between April and June, can take up a bit of space, but the homegrown flavour is well worth it
Kale, Black Magic Kale can be sown between March and June and harvested all the way through August to the following March.
Hardy winter vegetables such as Kale and sprouting broccoli will produce a sweeter more intense flavour during the slower growing months, which I can certainly verify based upon the rich flavours of the steamed Kale and sprouting broccoli I had with my dinner the other day.
This also got me thinking about our friends over in Canada, they have propa snow every year. But actually, the list of hardy plants that can handle even your snowplough weather is about the same as that in the UK believe it or not. The root vegetable known as Rutabaga in Canada got me curious for a moment though, until I found out that it’s just another name for a Swede. Another fab winter warmer. Don’t forget that you can also eat the leaves.