CAMBRIDGE — Many gardeners look on clay soil as a death sentence for plants. It’s compact, solid and seemingly impenetrable to roots and shovels, alike. Sticky in spring, cement-like in summer, this type of soil bedevils Dorchester gardeners, in particular, because there’s so much of it in the county.
But clay holds a number of minerals useful for plant life. The problem is how to make them available to the green community in your garden.
Recently, I sat down with a gardener who did exactly that, using no store-bought chemicals or fertilizers, but only natural ingredients, available to anyone for free.

Before Christiane Williams and her husband Ronnie moved to their home in Cambridge, they lived across the bridge in College Park, on a quarter-acre lot, where Christiane created a prize-winning garden in what started out as pure clay.
“When we bought our place, there was nothing there but a few trees. The soil was pure white clay,” Christiane told me. “Clay is not a bad thing. Clay is good at holding moisture during droughts and for holding the minerals that are necessary for plant growth; but to work with it, you have to amend it. All plants will grow well in clay if you amend it,” she said.
Born in France, Christiane grew up in the Champagne region. She knew what to do in College Park because she’d learned the technique, when very young, from her grandparents who raised vegetables and flowers in their village garden.
“You can’t do a large area all at once. You have to choose a spot where you want to make a vegetable patch, a flower bed, or whatever.” Because you’ll be digging, do the work in spring or fall, when the ground is soft.

To make her vegetable garden, for example, Christiane dug down about a foot deep in the fall. She removed the clay soil and put in home-made compost. Then she replaced the soil and added dry leaves and grass clippings on top. Finally, she covered the area with a black tarp and “let it cook all winter.”
As a child, “I saw my grandparents do it time and time again. By the following spring, you have good soil.” Do this in spring and the soil should be ready by fall.

Christiane makes her compost from dead leaves, grass clippings and kitchen waste – the remains of fruit and vegetables, including coffee grounds and egg shells, but never meat or poultry. How much green stuff to brown stuff? “No particular fraction, just whatever you have.” She shreds the leaves with her lawn mower, otherwise they take much longer to decompose. “Not only my leaves, but my neighbors’ leaves, too,” she said, adding that she asks them first.
You can even let the leaves, grass clippings and kitchen waste sit for only a week, then dig the mixture into the soil.
“Just let nature do its thing. If you have worms, they’ll do the composting for you and aerate your soil. You take advantage of everything that’s natural,” she said.

Use leaves from deciduous trees (that lose their leaves in fall). “I’m not going to use English ivy or any other nuisance plants in compost,” she said.
English ivy, an invasive, should be destroyed. It can grow from a single leaf and will strangle trees, shrubs and anything else growing in its path.
If you want to make quick compost, fill a large trash bag with dry leaves, add about a quart of water – or you can leave the bag open and let the rain “do the job.” In a few months, you’ll have bags of compost.
Some leaves take longer than others to break down. “Oak leaves take longer. Don’t even talk about magnolia leaves. They take forever,” Christiane said.

Some gardeners use straw, nut shells, wood chips, manure, weeds and peat moss in their compost. If you add manure, never put it near plants until it has matured, which takes a year. And think twice about peat moss. It’s acidic (clay soil is already acidic), contains few nutrients and comes from peat bogs formed over thousands of years. Many countries are worried about over-harvesting.
One factor that can hinder you when converting clay to good soil, however, is poor drainage, Christiane said. Her back yard, which measured 100 by 75 feet, had a grading and drainage problem. The neighbors’ yard was higher, so water would seep into the Williams’ property from the back and the side.

To remedy the situation, Christiane made a French drain. She dug a trench 1-1/2 feet deep around the edge of the yard, put gravel at the bottom, then perforated pipe and soil.
At the side of the yard, she staggered branches along the ground to slow down the water and keep it from washing away her soil. Later, she dug a pond 16 by 8 feet and built raised beds for flowers and vegetables.
It took three or four years to convert the clay to good garden soil. Most of the garden consisted of flowerbeds. They contained: Azaleas, larkspur, day lilies, peonies, kalmia, foxgloves, dogwood, a fringe tree, bay laurel, hydrangeas, seven or eight sorts of hosta, anemones, roses, ferns, phlox, wild ginger, wild milkweed, a snowball bush, wood poppies, bleeding heart, columbine and more. “Name it, I had it,” Christiane said, “It was very lush and there were lots of wild flowers that came back every year.”

Asked if it took a lot of work to maintain the garden, she said, “I didn’t have a lot of work, my yard was self-contained, made so I didn’t spend my life in it. Things like bleeding heart and columbine re-seed themselves. I worked at it in spring, mowed in summer and raked in fall.”
In the end, she had about a foot deep of rich, dark, garden soil, with clay underneath. Christiane also won a prize for Wildlife Habitat and Organic Gardening from the Better Environment Committee of the City of College Park.
Her achievements and love of nature offer inspiration to those of us who wrestle with clay soil. In the meantime, happy gardening!
Editor’s Note: Laetitia Sands is a master gardener in Dorchester County.