Tuesday, May 14, 2013

A Close Call

After over two weeks of warm and sunny weather, the last two nights have been very cold and produced a crisis of the kind northern gardeners have to face at least once most springs: a frost warning when many things are already up and growing. Our worst night was last night when the gods decided to remind us we live in Canada.

Empty pots covering plants to protect them from frost

It is a miracle that plants survive the month of May. In fact they gamble their very lives. They cannot wait too long before starting to grow, or they risk not having enough time to reproduce. If they grow too fast, too early, they run the risk of being killed or severely damaged by a late frost. What is a plant to do?

The problem is the same for us gardeners who, whether we like it or not, have to gamble. If you wait long enough, none of your plants will be endangered by a late frost, but then you will get fewer vegetables and things that could have started to bloom in summer will only appear in the fall. Some of these gambles are easily managed. For instance, I start my tomato plants from seed and grow at least twice as many as I will need. I planted out a few last week, well aware that it was too early and that a frost might come. The gamble is, if they do not freeze, a few of my plants will start producing earlier. If the frost kills them, like a general I have more bodies waiting to replace the fallen ones.

A frost warning, especially after a long warm period as we just had, necessitates a “branle-bas de combat”, in other words, a managed commotion where all available “covers” are called into service. Lots of things can be used: old sheets that kept you warm and are now requested to keep the plants cosy, floating row covers, pots, even wheelbarrows (in this case tipped over some lilies) can be put to good use.

The important thing is to know what to cover. A lupine is tough and cold resistant. An emerging lily is very cold sensitive. The frost is unlikely to kill it, but will deform the plant and the flowers. My approach is cover everything I can think of that seems fragile and let the tougher plants fend for themselves. These last two nights I mostly covered lilies, some annual seedlings and, of course, Mrs Slocum (see previous post), over whose pot I put a sawhorse on which I draped nothing less than a sleeping bag with a plastic sheet on top. The plastic is to prevent the sleeping bag from getting wet. In itself, it offers hardly any protection against frost. There was a little bit of frost on the plastic sheet on Monday morning, but Mrs Slocum was untroubled and had spent a good night in her sleeping bag.

Lotus Mrs Slocum covered with a sleeping bag to protect if from the frost

As it turned out, clouds moved in during the night, and temperatures last night did not dip below +2°C, and all this covering was a case of better be safe than sorry.

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