The Grand Illusion
For the past month and a half the temperature here hasn’t dropped below freezing even at night, and the high temperature has been in the high 70s [Fahrenheit] or low 80s almost every day. It’s also been not only warm, but dry, and I had to turn on the sprinklers a month ago to keep the lawn from turning to straw.
So, last week, I got to thinking that perhaps, just perhaps, I could plant my tomatoes. I don’t do gardening, except for a single modest flower bed, some perennials… and the tomatoes. The tomatoes are because my wife truly loves garden-fresh tomatoes. So we have a moderate sized tomato garden, and I thought that planting them a week or so earlier would mean they’d be ripe a week or so earlier.
When I mentioned this, she shook her head. “Not until a week after Mother’s Day. That’s the local saying.”
Ignoring that bit of folk wisdom, I made the mistake of saying, “We’re suffering global warming.”
She gave me a look that chilled the local warming, and I deferred on planting the tomatoes.
Two days after Mother’s Day, the temperature dropped 45 degrees, and it snowed on and off for two days. As I write this, it’s forecast to freeze again tonight.
But the forecast for the weekend is warm and sunny. I might plant the tomatoes early next week, more than a week after Mother’s Day.
If “folk wisdom” is simply anecdotal evidence reconfirmed over generations, then even if it’s subject to occasional exceptions or special cases, it’s probably useful, even though certainly not an absolute rule of nature.
The only distinction is that absent a rigorous procedure and rationale how the conclusions were reached (or subsequent rigorous examination) “folk wisdom” needs to be treated with skepticism.
Surely until quite recently, medicinal plants (genuinely effective in many cases) were discovered by accident rather than purposely looking for them, and what worked was passed on. However, details like interactions and contraindications were rarely determined, let alone passed on.
Medical matters, therapy, and diet, are areas where safety calls for particular skepticism before acting on folk wisdom; but planting times seem a reasonable category for giving it consideration; long-term change is often overwhelmed in the short-term by other variations.
For historical novels, there’s a lot of details to get right to avoid anachronisms, know the actual moon phase at the time of a battle, etc. For other fiction, there may be internal explanations for seeming anachronisms.
Mother’s Day in the US – which is at a very different time of the year than in other countries – has only been in existence since 1911, so there hasn’t been much time for the folk to get their wisdom together. Also, given that the vagaries of climate (and let’s stay away from micro-climate), mean that this wisdom would only apply to a specific part of of southern Utah at your elevation, not many wise folk to generate it either.
A hundred and six years is a long time in a small community.
May 15th is informally called ‘Ice saints’ in Dutch, and the four saints who’s days are 12, 13, 14 and 15 May are the ice saints. I’m not Catholic so I forget their names and don’t know why they are called the ice saints, except that meteorologically the chance of a night frost becomes less than 1% after May 15th in most of the country (in my coastal area it’s a bit earlier).
Folk wisdom is not to plant out frost-sensitive plants and seedlings until the ice saints are past.
If Mothering Sunday is recent, maybe an older tradition just co-opted that name once it became established on a relevant day, instead of an older saints-day or something like that, that had become obscure and forgotten.
With regard to global warming, my understanding is that you should expect such unusual cold snaps to happen *more* often. The reason, apparently, is that the jet stream that runs across the northern US and southern Canada, which ran straight across from west to east, is now taking a much more wavy path. Because the jet stream effectively blocks cold weather from the Arctic (and warm weather from the south), much colder air can descend on your location and the rest of the northern US than before (often followed in northern locations by unusually warm weather as the next part of the wave allows warm weather further north).
This new weather pattern is in fact thought to be part of global warming: the reason for the new waviness is that Arctic air has warmed more dramatically than mid-latitude air (as predicted), giving Arctic winds greater energy to displace the jet stream. However, underlying the turbulence is an overall increase in (average) temperature of more than 1 degree F in summer, 5 degrees F in winter. As temps continue to climb, this will eventually overcome the low-temperature effects of jet stream “waviness”, so that 30-40 years from now most of the unusual temps (at least compared to 40 years ago) will be on the upside.
So you’re right about global warming leading to earlier planting seasons on average (there’s a fascinating time series on Japan’s cherry trees dating back to about 800 AD showing that recent blossomings are about a week earlier than a century ago), but your wife is right about the risk 🙂