How to - Gardening Basics
To till or not to till
Just how much should you cultivate your soil in the spring and fall?
There aren’t many controversial issues amongst gardeners. As long as you don’t get into a chemical versus organic debate, we’re an easygoing bunch. But lately I’ve noticed some polarization over the issue of tilling. Some claim the less you touch the soil the healthier it will be. Others insist that cultivation is the only way to keep a light, well-drained, weed-free soil, especially in larger spaces. So, who’s right?
Angela Sommers, a landscape architecture technologist in the Calgary area, and owner of Heron’s Nest Landscape Design, leans heavily to the “do not disturb” approach, but allows that tilling is needed in certain situations.
The case against tilling
Sommers says in most cases, “what we want to create is what’s in nature,” which is topsoil covered by humus-rich, decaying plant life, with an insulating blanket of fallen leaves. By spreading amendments on top of our soil and covering it with mulch, we imitate that natural layering.
In the soil itself, a structure of air pockets, root systems and water channels, exists, allowing nutrients from above to get where they need to go. Tilling upsets this structure, undermining the soil’s natural resiliency.
Furthermore, there are millions of microorganisms that keep the soil balanced and healthy. When you till, these microorganisms are oxidized, or in other words, killed off. The soil’s initial fertility goes up because there is a surge of organic matter, explains Sommers, but soon drops off. “There’s nothing there building the soil.”
As far as tilling for weeds, Sommers says the reality is any weed problem will likely get worse if you do nothing but till. Dormant weed seeds are turned up, ready to grow now that they have air and light. Anything growing from rhizomes will be chopped up, actually helping them perpetuate. Building up soil fertility is the best way to fight even the worst weeds, says Sommers.
- Page 1: The case against tilling
- Page 2: When tilling may be necessary