Saturday, May 2, 2015

Gardening at the Boundary

That day, maybe a week ago, it really came down.

I know nothing about late spring snow. Nothing. When I was a child, in New York, it snowed during our Easter break -it was early April. The day prior was warm, even the day it snowed it was warm, so much so that I was out riding my bike in the street with my brother. Although it was cloudy, the big, wet flake snow came without warning.

This snowfall is different, intermittent pellets and flakes. It was windy too, driving the pellets hard. As is often the case, the snow did not stick. The snow was not the trouble at all. It was the cold that presented itself the following night. 

I woke to find a frost on the little wetland.

 Crystals coated all the leafed out, saturated-looking plants in the early sun.

The parsley I had just planted showed crystallization along its veins (interesting that this happens, no?).

The  cilantro.

The Virginia Wetleaf succumbed (but recovered) to the eight or so hours well below freezing.


The last frost date for our location is roughly May twenty. I do not think anyone would suggest that the last two months have had ordinary temperatures, we haven't. Since March, we have had days that topped out at 10ºF and 82ºF, although most have been in the forties through the sixties. Our March monthly average high temperature was nearly 46ºF and the April average so far is 59ºF. Daytime temperatures have long suggested I should be growing things that California is having trouble providing. Think twice. I watch the trees and the vegetable gardens. Only this week are the oaks beginning to show the chartreuse of spring and there has been zero garden activity.

Warm air masses, heated by their descent from the Rockies and Great Plains, move in from the south and west, and locally there is sunlight warming the thermal mass of land without the cooling influence of great bodies of water. The day warms nicely. At night, however, without the moderating influence of clouds, radiational cooling is strong. I recall a typical temperature differential in NYC to be about 15 degrees. Here, in Minnesota, I have seen 20+ as the norm. Beyond nightly cooling, there is always the threat of a cold airmass coming down from the north whenever the jet stream decides to do something funky. Minnesota is the common entry point for cold air, it is the reason people think this state is cold. 

Which brings me to another weather detail. I noticed the window box of just planted pansies was bone dry. What? I had watered it in, deeply, just the day before. Hmm. Something unusual had happened -dry air, exceptionally dry air. Two days after the snowfall, and the day of the overnight freeze, our relative humidity had dropped to 12%, twelve percent! Our dewpoint was nearly 1ºF by the late afternoon. Meanwhile, our high temperature was 55ºF and the winds were up. The water simply evaporated. Despite this, the pansies toughed out the freeze and drought, as those in the pot above attest.

The dry air, the sudden cold from the north, the high temperatures, the wind, no rain, and of course, heavy rain are all typical. We live at a climactic boundary with little to moderate each influence. This is the education of a gardener.


  1. I just moved back to Alberta after living in NYC for 4 years and I feel your pain. On the one hand it has been a gift to have an exceptionally early spring since it lessens the pain of having no magnolias. But I also have to counsel myself daily not to do something rash like plant anything out because we're at least 3 weeks ahead of when I would normally stop worrying so much about frost. And don't get me started about late snows. Even in June we get them... It's not a great climate to become an emotionally invested gardener. May you have better luck than me!

    1. Snow in June! May as well live in the mountains. I do think we are past major frost threat but one never knows. Good luck to you and your garden in Alberta!

  2. Maybe what fourists describes above explains part of why, in the late 1930's, my father moved from the rolling plains of central Alberta to Seattle, then on south to Portland. Here in the northern Willamette Valley, we (usually) have more moderate weather than Mound's, but predicting it is made interesting by being located at the western edge of the Columbia Gorge, as well as between two mountain ranges and near the Pacific Ocean. As a new gardener in the last 15 years, I have had to learn more about weather and have found it fascinating enough to tempt me (for about a day) to begin academic study of meteorology. Instead, I'm learning from what is all around. One recent kick: monitoring, in real time, the flight data from my son's recent trip from New York to Seoul, where the a/c flew a great arc up to within 15° of the North Pole then west and south over the northern seas and central Siberia before heading east to that it could best avoid the easterly jet stream winds...and then three weeks later, monitoring his return flight, which had two hours' less flight time because the a/c rode the jet stream east. I sure do enjoy your reports from Mound, Leslie in Oregon

    1. Leslie, as you tell it I well recall my brief time in Portland. Love the region and all its varied topography, ecosystems, and weather. It's a lovely place to garden. Too boot, meteorology is a favorite of mine. When I was in high school I briefly considered going into the field.