How to Improve Your Garden Soil

Garden soil

Gardeners know that dirt is and should be treated like, well, dirt. We also know that dirt is not synonymous with soil, and it is typically what winds up under fingernails and what’s tracked in by shoes — essentially dead soil. Soil, on the other hand, is a living ecosystem and we should give it the reverence it deserves because we know that healthy soil produces vigorous leaves, healthy crops and an abundance of flowers. With that said, here are top ways to boost your soil and reap the benefits.

Garden soil
Allison Krivoruchko

In the Field

“I use cover crop SCM120, ordered from Peaceful Valley Garden Supply in Grass Valley,” says Allison Krivoruchko, a Marin Master Gardener and soil expert. “I plant it in October and then cut it down at the end of March when the cover crop flowers are 50 percent in bloom, then put compost over it for a month before planting.” She also recommends using compost tea from Harmony Farms once a month during the growing season.

The Goal

Strive to build up the existing soil so that air, water, and nutrients are easily accessed by plant roots. Adding organic matter to the mix is a superior way to give roots more opportunity to penetrate the soil.

Test Time

Learn what’s in your soil and you’ll discover whether organic material or nutrients/fertilizers should be added or if the pH should be altered (you can purchase a soil test kit at your local garden store). It is important to test before starting a new garden or if your garden’s health is declining.

Garden soil

Much About Mulch

Enrich your soil with a layer of mulch to help conserve moisture, add organic matter and suppress weeds.

Got You Covered

Consider planting a cover crop that includes vetch, clover and fava beans over bare winter soil, then cut it down and chop it up directly into the soil. This process loosens the soil, transfers the nitrogen from the atmosphere into the soil and adds significant organic matter. Cover crops also protect soil and control weeds in the off-season.

Like Us

Soil has the same basic needs as we do: food, water, air, and shelter. But unlike us, soil always needs nitrogen because nitrogen feeds plants and soil organisms. Good sources of nitrogen are manures and green grass clippings added as amendments.

Do’s and Don’ts

Avoid digging, walking on or rototilling wet soil, especially clay, because it compacts the soil structure and squeezes the air out, leaving limited room for root growth or for organisms to breathe.

Worm Business

Instead of breaking your back digging, add worms and let them do the hard work while you are sheet mulching (putting a layer of material like cardboard over an area to kill weeds before planting). Worms leave nutrient-dense manure castings and help aerate the soil.

The Basics

For most purposes, add a complete organic fertilizer and apply as recommended. Organic (not synthetic) is best because the nutrients and minerals occur naturally.

This article originally appeared in Marin Magazine’s print edition under the headline: “Dirty Secrets.


Kier Holmes

Kier Holmes is a native, Marin-based landscape designer who works at M2 Design and Construction, for over 15 years, has artfully designed and created sustainable gardens that are dynamic year round. She also writes for Gardenista, is an elementary school garden educator, a garden speaker for adults and leader of the Garden Club for kids at the Mill Valley Library. Holmes readily admits that she is a nerd about all things plant related, and can geek out on a dinner-plate dahlia like nobody’s business. Her natural habitat is among flowers and her hands are almost always dirty.