Here's WHY Your Hillside Garden Loses Soil Every Summer

In 1986 I ran two short bean rows straight downhill on the first terrace I'd built — not by plan, but because that's the direction the space happened to run. By the end of August those two rows had lost two inches of surface soil to summer thunderstorms. The cross-slope rows six feet away, on the same terrace, in the same soil, under the same rain, had lost nothing measurable. That was the experiment. I've been running everything on contour since. Hillside garden soil doesn't wash away because the rain is too heavy or the slope is too steep. It washes away because downhill rows act as channels — they concentrate water in the center of each row, accelerate it, and carry your topsoil to the bottom of the slope. The USDA Natural Resources Conservation Service has been writing this down since the 1930s in Conservation Practice 330 (Contour Farming) and Practice 600 (Terrace), and the principle is the same whether you're farming three hundred acres of grain or gardening three hundred square feet of Cherokee Purples on a hillside in Buncombe County, North Carolina. This video is about the single most important structural decision a hillside gardener makes: running rows across the slope rather than down it. It's also about the companion practices that make contour gardening work — mulched paths as infiltration zones, perennial strips above retaining walls, and how to level a bed on a slope with nothing more than a four-foot carpenter's level and a wooden stake. I take you through the three scales: a single sloped garden bed, a multi-bed system on a slope, and a full terrace system with retaining structure — and I cash out what thirty-eight years of contour management has built at 2,400 feet on a hillside that was washed-out cow pasture when I bought it in 1985. WHAT YOU'LL LEARN Why downhill rows act as erosion channels and contour rows act as contour structures — the velocity and detention-time physics behind it How to orient any garden bed on a slope: level from side to side, long axis perpendicular to water flow The role of mulched paths (4–6 inches) as infiltration zones between contour bed bands Why a perennial strip above each terrace retaining wall is the anchor the structure depends on — and why comfrey is the right plant The NRCS Conservation Practice 330 and 600 rationale behind terrace design and contour farming The 1986 two-row experiment: what two inches of lost topsoil per season means compounded over a decade What 38 years of contour management, mulched paths, and leaf-mold addition built from washed-out cow pasture: from 6 inches to 14 inches of workable topsoil SOURCES USDA NRCS — Conservation Practice Standard 600, Terrace (PDF) https://www.nrcs.usda.gov/sites/defau... USDA NRCS Texas — "Conservation in Your Backyard: Terracing" (PDF) https://www.nrcs.usda.gov/sites/defau... Iowa State University Extension — "Gardening on Slopes and Hillsides" https://yardandgarden.extension.iasta... CONNECT Drop a comment and tell me about your slope. Are your rows running across it or down it? What's your soil type and what does your erosion look like after a hard rain? If you're in the mountains — Appalachians, Smokies, Blue Ridge, Ozarks, Rockies — I especially want to know what your terrace situation looks like. Tell me the state and county, or the elevation if you know it. I read every one.