I'm always a little surprised when I encounter people with that question, because in my decade of growing vegetables, I never tilled the soil but one time.
And it really wasn't I, but my husband, and he used a hand tiller (a hand tool with three prongs on one end), not a rototiller. The only reason we did that initial tilling was that due to the thick clay soil where we lived at the time, the local organic gardening guru recommended tilling certain amendments into the soil before the first planting.
To his credit, he stated that this was the only time you should till your garden. However, I've discovered since then that even that little bit of tilling wouldn't have been necessary. I'll get to that in a moment.
The reason people till their backyard garden
If you think you have to till your garden every spring, there is one reason for it, and one reason only: it's how farmers have loosened the soil in their fields for millennium. It's the same reason people think they have to separate the crops they want to grow, planting all of one kind of vegetable down a long row.
People see how farmers grew their crops, and think they have to pattern their kitchen garden the same way.
What if I told you that if they were doing it right, not even farmers would need to till their soil? I'm not going to get into no-till farming, but I want to let you know that there is a small but growing movement of farmers learning and applying the no-till method of growing to their large fields.
Why tilling is bad for your garden
Native soil teems with healthy micro-organisms that are eagerly waiting to help plants get the nutrition and moisture they need. It also teems with earthworms.
Good stuff, right? But there's one more thing soil teems with, and it's not so good: weed seeds.
Therefore, when you till soil...
...you disturb the fragile ecosystem within it. And if the micro-organisms can't do their work of delivering nutrients to the plants' roots, the plants won't be as healthy as they might have been.
...you chop up earthworms (that kills them. All those pieces don't magically turn into new worms).
...you compact the soil more than you loosen it (assuming you're using a tractor, rather than a broadfork or hand tiller).
...you bring to the surface weed seeds that would have otherwise stayed buried deep and taken years, even decades, to find their way to the surface and germinate.
The benefits of no-till gardening
The benefits of not tilling, then, are the opposite of all those problems: the soil ecosystem remains intact, the earthworm population (which provides awesome natural fertilizer to your garden) is not depleted, the soil doesn't get compacted by heavy machinery, and you don't end up with a hundred times more weeds to pull.
In addition, you save yourself the cost of a rototiller as well as the annual dreaded chore of tilling.
The final benefit is that you end up with much more nutritious soil, because of what you do instead of tilling to create loose, rich, loamy soil.
The how-to of no-till gardening
There are five steps to creating a no-till garden.
Step 1
Measure out thirty to forty-eight inch wide beds, up to ten feet long. Space each bed one to three feet apart.
You can build a border for these beds with pressure-treated or cedar lumber, or with rocks. Or you can leave them without a border. It depends on your circumstances and preferences.
When you create beds like this with space in between, you won't have to walk on the soil next to the plants in order to work with them. This means you won't be compacting the soil.
Step 2
Soften the soil by piling up organic matter into the beds, then letting it sit and compost for at least six months.
I detail how to do that in this post about building a permaculture raised bed.
Step 3
Leave no area of dirt uncovered. Fill in the spaces between your main food plants with flowers, herbs, clover, or wood chip or bark mulch.
You do this for two reasons. First of all, if you intentionally keep the dirt covered, nature won't work as hard to cover it with weeds. Second, the soil in between plants, even if not covered in mulch, will be shaded and therefore will stay cooler and more moist longer, even during a drought.
Step 4
Always leave some roots in the ground. In other words, at the end of a plant's lifespan consider cutting it off at its base and leaving the root in the ground. This will keep the soil micro-organisms happy. Whether or not you leave a certain root in the ground depends on the plant. For example, tomatoes are notorious for developing fungal diseases at their roots, so it's best to always pull those out at the end of every growing season.
On the other hand, consider leaving the roots of peas, beans, and lentils in the ground, because the nodules at the ends of the roots will continue to put nitrogen back into the soil.
Step 5
Continue to add organic material to the bed. If you get into the habit of using several inches of wood chips, bark mulch, leaves, and/or straw everywhere in the garden, this step will happen automatically.
Another way to add organic matter is to bury kitchen scraps and grass clippings around your garden crops as you accumulate them. Dig a hole six inches deep and with a diameter large enough so that the material you put into the hold can be spread out to a layer no more than two inches deep. Then, cover it back up.
Some gardeners, even those with small plots in a small backyard, will grow cover crops in bare beds, then after a couple of months dig them up and turn them over. A few months later, this material will have turned back into soil.
No-till gardening is a no-brainer!
I hope I've convinced you that no-till gardening is the best way to grow your own food. It may seem more labor-intensive at first, and maybe it is the first year that you build the beds. But as long as you follow the steps outlined above, in the long run this method of growing vegetables will end up saving you time and energy.
And your produce will be a lot more, um, productive. ;)
