planting peas, with mendel in mind
PLANTING PEAS—that first traditional first task of each new food-growing year—took on new significance this spring. I’d just finished watching a lecture on Gregor Mendel and his pea-breeding experiments in an online biology class I’m taking, when the snow finally melted and the soil warmed enough—well, almost enough— to have at it. The peas I like best, and how I plant them, all with a new reverence for the genetics built into a single Pisum sativum seed:
Turns out Mendel started his scrupulous research by simply going down to the market in Brno (in the Moravian region of what is now the Czech Republic) and buying 34 varieties of peas from several seedsmen. (Makes me a bit less self-conscious that I ordered eight kinds to grow in my garden.)
It was no accident that Mendel chose peas as his subject, I also learned recently: They didn’t take up much space in the confines of the monastery garden, and most important: The structure of a pea flower, with its enclosed fertilizing organs, means that random cross-pollination isn’t likely.
Like a good gardener (and “an amazing scientist,” said Professor Eric S. Lander of MIT, who’s teaching the free EdX online class I’m auditing and himself one of the principal leaders of the Human Genome Project) Mendel didn’t rush into things. He was patient enough to first set up his controls.
He bred the 34 peas “to see if they transmitted their traits faithfully,” said Dr. Lander, which took two years, and resulted in 22 of the 34 making the cut for the actual experiments that followed—the ones about wrinkled and smooth seeds, and short and tall plants and so on that we all learned about in school.
In the current “class” of Introduction to Biology: The Secret of Life, we even read Mendel’s 1865 paper on his pea experiments (translated to English, of course, but nevertheless rather hard going). The intro course (its promotional video is at the bottom of this page) has been taught by the dynamic Dr. Lander for 20 years, but this is its–and his–first time online. The 2013 “classroom” is a room full of MIT undergrads and some 40,000 of us unseen virtual types around the world.
from classroom to garden: time to plant my peas
AND THEN, thanks to a few sunny days, it was time to plant some peas in my non-virtual life. I cultivated the soil along the edge of two of the raised beds—choosing the side that won’t cast shade on the rest of that bed when the peas are up on trellises, so I can use the other space, too. I made a wide furrow a couple of inches deep with a hoe in the loosened soil, then sprinkled legume inoculant (below) into the furrow very lightly. (You can also moisten the seeds slightly in a bowl and sprinkle the powder or granules onto them, mixing with a spoon, before planting.)
I read the details on the packets while sitting on the edge of one bed in the strengthening March sunshine, making my labels. Some promised tall vines; some short ones that would require no staking. Some of my plants will have purple flowers, others white. Among the seeds were those whose coatings are yellowish, some green, and one favorite variety—‘Schweizer Riesen’—are a distinct rosy-green (that’s its colorful flower in the top photo; it’s one of two peas I always grow that are are profiled here). Mendel would have noted every detail.
A few varieties I grow are for shelling, another one or two snowpea types. In Mendel’s garden–even among his 34 peas–he would not have had peas that become plump, edible-podded “snap” types, a discovery that wasn’t to make it to the seedsmen’s shelves until about 100 years after his time. It was made by a sharp-eyed plant breeder not in Moravia, this time, but in Montana, when Dr. Calvin Lamborn of Gallatin Valley Seed Company crossed a tight-podded rogue pea with a snow pea…which eventually led to the famous ‘Sugarsnap’ (Lamborn’s 1979 All-America Selection medal winner). Others had tried before, but failed, to perfect and popularize that tasty blend of genetic traits. (Lamborn made “People” magazine that year for his delicious achievement.)
THINKING WITH GRATITUDE about plant breeders–those working in the name of science, and of commerce, and of just plain good eating–I planted my peas in thick rows, a few inches across and an inch or so between seeds in all directions. I don’t get all precision-gridded about it; I just sprinkle. Years ago, I used to make a perfect grid in the cultivated soil with my dibber, poking inch-and-a-half-deep holes every inch or 2 apart, dropping one seed into each hole. Once more measured and controlled, I’ve lately become a scatterer (scattered?); you can be tidier if you like. The peas seem cooperative either way.
Once the seeds are in, I rake the soil that was dislodged by making the furrow back into place over them, tamp it down with the head of an iron rake (above) so they’re covered about an inch and a half below the surface, and pray the chipmunks don’t notice what treasure I have just buried in their neighborhood. I usually pin down netting over the bed, right on the soil surface, until the peas are well up, when keeping woodchucks or rabbits at bay instead will become my primary task.
In 60-something days the first of my eight varieties of peas will flower, and start to produce, and I will soon after–forces willing–have a few weeks of precious harvest. In the fall I’m registered to audit a class not on genetics nor even horticulture, but on the chemistry of food, called Science and Cooking: From Haute Cuisine to Soft Matter Science, given at Harvard and offered as the biology one is via the EdX system. Maybe I’ll learn what’s really happening when those peas take the next step out of the earth, toward the stove and table?
the promo video from mit’s intro to biology, via edx