In the last post, we talked about switching to no-till in order to preserve the soil’s micro-biome, which is crucial for bringing crops to their full nutritional capacity. This post focuses on another reason not to till: weeds.
If you’ve ever grown a garden yourself, you’ve probably found that when you come out with your seeds in the spring, your garden plot is covered with debris, including plants you didn’t put there. The easiest way to get rid of that mess is to rent a Roto-tiller, which turns the surface of the soil under and brings a lower layer to the top. It looks great: loose and clean and ready for your spinach seeds. But three weeks later, your row of spinach is engulfed by thousands of invaders. Where did they come from? You planted spinach, not chickweed!
They came from that lower layer, which is full of dormant seeds that pop to life when you turn the soil and expose them to the warmth of the sun.
That same process takes place on a much larger scale when you till a 40-acre field with a tractor. Industrial farming solves the problem by spraying the field with Round-up, which kills everything but plants genetically engineered to tolerate it. Well, we don’t use Round-up, so we had to pull those weeds by hand, which takes a long time.
But when we stopped tilling the soil, we stopped bringing those seeds to the surface, so they stopped germinating.
There’s a trade-off: it’s hard to sow seeds directly onto un-tilled soil because of all that debris, including left-over weeds. So instead of turning under that debris, we cover it with compost. After a couple of years, most of the weed seeds are pretty well buried. And as long as we don’t turn over the soil, they stay that way.