Home & Garden Columns

The Dirty Lowdown on Working With Our Lowdown Dirt

By Ron Sullivan
Friday August 11, 2006

One of the hardest things for new gardeners here—both experienced gardeners who move here and long-time locals who get inspired by the goddess Flora—is our dirt. Most of us have to garden on clay soil here, and those of us in the flatlands generally have the heaviest, the historically most stomped-on and sometimes most-contaminated clay.  

It’s ruff, it’s tuff, it’s so heavy you might think you’ve been teleported to Jupiter (assuming there’s soil on Jupiter at all, which I doubt) and it sticks to your spade like massed molecular bulldogs. People get desperate and rototill their whole yards, or double-dig beds. That’s OK if you’re young and you want some resistive exercise, and it does give immediate, fluffy results.  

It’s not the only way, though, and skip rototilling if you have trees in the yard. In heavy soil, their roots are likely to stay in the top couple of feet of soil because they need oxygen.  

If you can use the soil you’ve got, you have some advantages. Clay retains nutrients well. Use organic matter—compost, chips, sawdust with nitrogen added. Treat it as an ongoing need. 

If you have soil so compacted it’s like concrete, well, here’s what has worked for me.  

I started with gypsum—scratched it into the clay with a stiff rake, watered it, repeated rake and water every few days for a week or so in the fall. It dissolved slowly, milkily. After that week, the soil was beginning to yield just a bit, so I planted starters. In one plot, those were rescued and discarded fortnight lilies and freeway daisies; in another where I took a longer view, I planted native shrub salvias in back and some laterally spreading odds and ends I got from a friend in front.  

I worked the first plot hard; I was young then. I waited only till the following spring to start planting natives, and in a couple of years I had a thriving garden that included things like flannelbush that need good drainage. I could throw a spade into it spear-style and it would go in to the hilt.  

The second plot, I took my time, after two of us hurt ourselves on an attempted asparagus bed. Near that was a gravelly bit that had been a parking space. Nobody who scratched at that accomplished much, and it was of course nastily contaminated.  

I did the gypsum trick and planted those salvias and for a decade they’ve provided cover for our towhees, finches, and robins, and scent for our home. They also took up some of the crap the parked cars had left behind, and sequestered it harmlessly. The soil’s more permeable under them than elsewhere in the yard, and more like its old self.  

The other castoffs, just shallowly planted at odd intervals whenever I got them over the years, rendered the front tillable in that same time. It didn’t have to run that long, so don’t think this works only for the very patient. Some pioneer plants and minimal sweat will work where the most grimly determined attacks on clay will just let you grow the one thing we all do—tired.  


Ron Sullivan is a former professional gardener and arborist. Her “Garden Variety” column appears every Friday in East Bay Home & Real Estate. Her column on East Bay trees appears every other Tuesday in the Daily Planet.