To till, or not to till—that is the question.

1. Sowing Weeds

Did you know that there are 140 weed seeds, if not more, in a pound of dirt? Some even call this amount a “conservative estimate.” Farmers often till their fields at night to combat germination of these seeds, but grasses and large-seeded broadleaf seeds sprout well at any time of day. It only takes a breath of air to awaken these seeds! If you till at night be sure that you don’t have any light at all: small-seeded annual plants can germinate in moonlight or even the light from a flashlight.

But what about existing weeds, you ask? The trouble with existing weeds is that they’ve got roots, and all plant energy is stored in the roots—that is why you can hack a bush or tree to pieces and watch it regrow within months. These roots are chopped up when you till; being chopped sends what is left of a plant into a sprouting tizzy. This is why you cannot get rid of dandy-lions without getting that cursed taproot. I admit that you may kill a lot of weeds this way and add to your organic matter a little, but it is still counter intuitive.

But this is hardly the worst.

2. Soil Structure

Tilling destroys the natural structure of the soil. I understood this beforehand, but my books fortified this. Abandon the industrial farming paradigm and think about the natural process for a few minutes.

I’m imagining a tall pine tree, join me. What do you see at the base of the tree? I find pine needles in a mat as thick as three inches; these needles decompose slowly to nourish the tree in the future. This is a pristine picture of recycling: anything unused by the tree for reproduction is reused. Nevertheless, only the topsoil is enriched, and no wonder. This is precisely why plants spread their roots through the topsoil for nourishment; deep roots merely add support to the plant.

Tilling destroys the value of the topsoil by mixing it with the layers below. The sudden influx of oxygen causes a huge increase in the aerobic bacteria’s population, but without access to the surface oxygen they will slowly smother. Without the aerobic bacteria organic matter is digested only by the anaerobic bacteria, because their population is smaller within the topsoil it takes much longer to take over the process.

What Happens Over Time?

I am sad to say that tilling does have a short term benefit, otherwise no one would ever till their field. After tilling, when the aerobic bacteria go wild, there is a burst of incredible nitrogen production. This production is so much faster that the organic matter is reduced faster than normal. Over time the organic matter in the topsoil, and the topsoil itself, is reduced by this process. The prairies in the USA were some of the richest soils in the country, but after seventy years of tillage the organic matter has fallen to 1/5^th of its former level. One day this may worsen to the point that the southern deserts grow northwards.

How to Aerate Your Garden Correctly

The hand-made Gulland Forge Broadfork; click the image to visit their website. (Photo © by Gulland Forge.)

I use a broadfork to aerate my garden without disturbing the composition of the soil. A broadfork is an interesting tool with a few uses: aeration; harvesting of root vegetables; and some stress relief. To use it, just set it in your garden and step on the crossbar; in clay soils, like mine, you may have to jump on the crossbar (but thankfully this broadfork can take it). Once the heavy tines are in the soil you pull back and rock it forward. Done! Move down the bed without stepping in the soil, if possible, to avoid compaction. You may have to work perpendicular to the edge of one side of your garden and make two passes to avoid compacting the soil (which wastes your effort), but it is easy to do even for beginners like me.

I am not affiliated with Gulland Forge, and make nothing if you choose to buy their product. Harvey Ussery suggests the use of a broadfork, and has a very good article on the Soil Food Web, and it was there that I found this product. I know the price is somewhat steep on the broadfork from Gulland Forge, but it has taken all the punishment I’ve given it without showing a sign of stress. In addition, it can help with harvesting of carrots, potatoes, and beets.

Save your topsoil by using broadfork instead of that old rototiller.