As a child, I remember Grandpa saying that tomatoes don’t like to get their feet cold. He was patient and would never set plants out before June. By then, there was not a chill in the air, even at night. My parents rarely started tomatoes inside, and claimed their volunteer ‘German Pink’ tomatoes came up and outgrew those plants anyway. No one ever heard of soil thermometers. They relied on common sense and experience. Just as mothers would not let their children go out in the winter without a coat, Mother Nature knew when it was safe for her little sprouts to be above ground.
Today, I witness this orchestrated plan for all the self-seeding annuals each spring at Heritage Farm. Seeds dropped in the fall, reliably self-sow and weave their way through my garden at just the right time and place. Grandpa Ott’s morning glory and other self- seeding annuals bide their time until conditions are perfect, never getting themselves frozen. Violas appear early and profusely once the coast is clear. Love-in-a-mist and ‘Radio’ calendula sprout like weeds. I can always expect later appearances from borage, dill, verbenas, vining petunias, night-scented tobacco, and kiss-me-over-the-garden-gate.
Unfortunately, I can’t claim to be as responsible as Mother Nature. As I’m looking at empty raised beds in the display garden feeling the strong heat from the May sun, I am convinced freezing temperatures are a thing of the past. The plan begins innocently with setting out a few eggplants and tomatoes, then thinking marigolds and purple basil would make a good-looking border combination—bam—before I know it, my garden is on its way. But inevitably there is another frost, and some morning my plants will have turned into clumps of withered stems with brown burnt leaves. Blooming in the path nearby, however, are bright little pansies that took care of themselves looking up at me with smug, cheerful smiles. What these little pansies knew was it’s not the air temperature, but the soil temperature that makes it safe. The ground that time of the year is always cooler than the air temperature, making it ideal for violas but not for tender annuals.
But really, how often is the soil temperature a topic of conversation. Gardeners want to talk about the fun stuff, like the latest gardening tool, growing tomatoes upside down, or a new greenhouse. It is easy to forget about the basics, like soil temperature.
Ironically, as I am writing this, outside my window a Seed Savers Exchange staff person is walking by carrying a flat of bright green tomato plants—a beautiful sight. We have been sending tomato and pepper transplants out to gardeners since March. No wonder it is tempting to forget about the warmth of the soil, when transplants are readily available.
But this year I will not be fooled by that first warm day. I will instead take my cues from Mother Nature.
Photo: Diane Ott Whealy
Photo of Diane: Jim Richardson