Digging shallow

This week I skimmed off some more lawn, this time to make space for new sun-loving pollinator plants. I ordered the plants last fall, including a false aster (Boltonia asteroides) and a northern blazing star (Liatris novae-angliae) for this particular spot.

Boltonia should flower profusely in August and September

    When I last visited this topic, I was despairing of being able to plant this year because of the depredations of our puppy, Lola. Fortunately, her daycare has reopened to all comers, so I’ll have some Lola-free days for gardening. That will make this project a lot easier and less aggravating.

    The planting area I’d chosen surrounds our little garden pond. The pond is an artificial creation, an 800-gallon black molded plastic tub sunk into the ground within a circle of lawn in one of the sunniest parts of the garden. When the pond was installed in 1997, the contractor edged it with bluestone. He also set randomly placed bluestone squares and rectangles into the lawn around the perimeter. 

Bluestone around the pond before sod was laid down to make the lawn in 1997

I’ve always liked the pattern he created, but now those stones are taking up space I want to use for attracting native insects.

    I used a crowbar to pry up three stones at one corner, between a spreading Japanese maple (Acer palmatum) and a dwarf Colorado blue spruce (Picea pungens ‘Globosa’). 

Then I carved away the sparse grass—mostly moss—that had grown around the stones and trundled it to the compost pile in the wheelbarrow.

Clods of grass and soil will make good compost

    The soil in this area is quite sandy. There’s a temptation to turn it and dig in soil amendments such as compost and composted cow manure to give the new plants’ roots a soft, cushy bed. I’m holding myself back, though.

    Scientific testing has proved the conventional wisdom about “improving” the soil before planting to be wrong and counter-productive. If I turn the soil, I’ll disrupt the top few inches where most of the biological activity takes place, the soil stratum called the rhizosphere. I’ll break up the architecture created by soil inhabitants such as fungi, bacteria, nematodes, earth worms, and insects. 

Electron micrograph of soil microbes-courtesy of Pacific Northwest National Laboratory

I’ll slow the work they’re doing breaking down organic material into nutrients that my plants’ roots can use. I’ll also bring weed seeds to the surface to germinate, and I’ll introduce a rush of oxygen that will burn through organic material. 

    If I needed to add amendments to this bed, I should use the no-till approach and layer them on top. Soil organisms would incorporate them in their own time. For now, though, I’m not going to try to make rich, ideal garden soil for these native plants. It’s not what they’re used to, and it’s likely to give the advantage to their competitors, such as nonnative weeds.

Why give the weeds a leg up?

    Instead, I just spread the soil that I’d separated from the clumps of grass over the 5-by-5-foot area, covered it with some landscape fabric to discourage weeds until planting time, and surrounded the newly dug area with another hopeful construction of metal posts and wire fencing. Puppy proof? I hope so.

Ready for planting

 

Full circle in a lifetime

My generation has lived through a sea change in how we conceptualize soil and fertilizer. We’ve come a long way from uncritical acceptance of chemical products after World War II.

       Today every school child hears about how the soil cycle works.  In undisturbed fields and forests, nature returns nutrients and organic material to the soil through a continuing process. Plants use sunlight, water and soil components to grow. Dead leaves and branches fall to the ground, decompose, and feed soil organisms that in turn provide nutrients for the next generation of plants. 

Leaves decompose into soil

    To understand how soil can be improved, New England school children learn that the Wampanoags added a fish to the hole when planting their hills of squash, beans and corn. As the fish decomposed, it fertilized the plants.

    So why didn’t I hear about building soil when I was growing up? It was because of something that happened between New England’s bucolic past and my birth in the Baby Boom.

    In the early twentieth century, German chemists invented an industrial process for fixing nitrogen from air, ushering in a radical change in the way farmers and gardeners thought about soil fertility. For a while it seemed as if synthetic fertilizer would replace traditional soil amendments such as manure and composted plant material. 
 
    During the twentieth century, the combination of manufactured high-nitrogen fertilizer, new high-yield grain varieties, and potent pesticides like DDT enabled the developed world to increase food production. Starting in the 1960s, a Green Revolution followed for areas of the Third World where famine was a chronic killer.

      I didn’t know it when I first encountered chemical fertilizer at age four, but I was living in a unique era in gardening history. Because I grew up with them, I thought those bags of 5-10-10 had always been around. Before the slogan became a joke for druggies, I remember a DuPont poster in my tenth grade chemistry classroom touting “Better Things for Better Living . . . Through Chemistry.” 
 
    But there was a dark side to farming with the new chemicals. Starting in 1962, Rachel Carson’s Silent Spring awakened Americans to the dangers of indiscriminate use of pesticides, exposing how DDT spread its lethal effects up the food chain. Meanwhile, soil scientists were noticing that intensive crop production with chemical fertilizer did not maintain soil fertility, and soil and water were being poisoned by over-fertilization and overuse of irrigation.

    As Americans questioned conventional ideas in the sixties and seventies, J. I. Rodale’s magazine Organic Gardening started to gain traction. Rodale had founded his magazine in 1942, with Albert Howard, a British pioneer of the organic movement, as associate editor. Organic techniques hadn’t completely died out with the advent of chemical fertilizer, of course, but there had been enough mass forgetting that the ideas Rodale proselytized were initially regarded as somewhere between cranky and dangerous. As the counterculture grew, his message found receptive readers.

    Seventy-four years after OG’s birth, there’s organic food available in every supermarket, and gardeners like me aim to improve soil without chemical fertilizer. Living through such a radical change in point of view makes me wonder what shibboleths the next generation will find to be dangerous and unjustified.