Although tilling the garden is often seen as a springtime chore, some gardeners prefer to do it in the fall as part of their preparation for winter dormancy. They might want to till under weeds that got out of hand during the summer, or they want to break ground on a new garden plot.
It turns out that tilling in the fall (or any time of year) isn’t very beneficial to soil. But the good news is that there are other ways to reach the goal of fall garden bed prep.
Unless you are starting a new garden bed in compacted soil, it’s best to avoid tilling at any point in the year. No-till methods of deep mulching, adding compost and organic matter, and preserving soil structure are better practices than routine tilling.
First let’s get into why tilling isn’t usually the best thing for the garden, then I’ll share a couple of alternatives to tilling that will still get your garden ready for the next growing season.
Is fall a good time to till the garden?
Fall is a good time of year for a one-time till to create new garden beds. Although there are no-till methods to break new ground, sometimes compacted soil can benefit from tilling to loosen up the dirt, add amendments, and work in organic matter such as compost.
If you complete this work in the fall, then the worms and microorganisms in the soil will have the winter to break down the additions and start creating fertile soil for spring planting.
It will be essential to cover the soil with heavy mulch to prevent exposure to months of winter weather.
If your area experiences heavy rain through the winter, then bare soil will be more likely to wash out from high spots to low spots, such as from the garden beds into the paths. On any degree of slope, garden beds may also experience soil runoff during heavy rains.
Cover the soil with a thick layer of organic mulch to avoid this. The mulch acts as a barrier to hold the soil in place. Even better, come spring, the mulch will help prevent weed seeds on the surface of the garden soil from sprouting since it blocks the sunlight from reaching the seeds.
Some weed seeds will still work their way through, so it’s not a complete preventative. But pulling the weeds is much easier when they’re rooted in loose mulch and not compacted dirt.
If you’re not sure which mulch would be best for your garden, here’s a breakdown of six popular mulches to help you decide: Best (Free!) Organic Mulches For The Home Garden. PS, woodchips are my preferred mulch.
Established garden beds do not benefit from being tilled in the fall. Tilling will destroy the soil structure and beneficial organisms, and it could take years for them to return. The University of Nebraska studied what even a one-time till does to soil, and they found that it took a few years for the full array of microbes to return to previous levels.
There were many other observations from the study, which you can read here.
A better option is to top-dress with compost and mulch and allow it to overwinter. In the spring, move the mulch aside and plant directly in the bed. I’ll share a few tips on that in a moment.
Natural Resources Conservation Services in Iowa also recommend against tilling established garden plots.
In this article, Barb Stewart, agronomist for the NRCS, states, “Tillage can break up soil structure, speed the decomposition and loss of organic matter, increase the threat of erosion, destroy the habitat of helpful organisms and cause compaction. Each of these potential outcomes negatively impacts soil quality.”
So unless you are breaking up a brand new garden plot, skip tilling this fall and use some no-till methods to start your new garden.
Ways to prepare garden soil without tilling
There are several ways you can improve your soil without tilling so that come spring, your garden is prepped and ready to be planted. These methods are used widely in the no-till gardening community. I also use them in my garden with great success.
Add organic matter like compost to established beds
Organic matter is one of the components of soil, alongside water, oxygen, and minerals. Many things qualify as organic matter, such as plant roots, worms, microorganisms, and compost. These elements add to soil quality by improving drainage, adding nutrients, and fostering soil life.
In a nutshell, adding organic material helps you build high-quality soil for your garden vegetables and flowers. And it’s a simple thing to do. As you’re cleaning up and removing old summer plants in the fall, instead of tilling the beds, add a layer of compost right on top.
A few inches of quality compost, whether purchased or homemade, will eventually work its way down to the soil without needing to be tilled. Worms, birds, and other bugs will churn the soil as they move and hunt for food. When you dig a hole to plant a seedling in the spring, you will also work in the compost.
Even plant roots help mix up soil layers, so don’t feel like you have to till the compost into the soil to get the benefits.
Use cardboard and compost to make new beds
Fall is the perfect time to establish new garden beds, and it’s easy to do without tilling. In brief, cover the new area with overlapping layers of cardboard, then lay down 4-6 inches of compost on top of the cardboard. Cover that with a 2-4 inch layer of mulch, and by spring, your new beds will be ready to plant.
Charles Dowding is considered the “grandfather” of no-til or no-dig gardening. Watch his video to see how he established a new bed right over a lawn without any tilling. He uses the cardboard and compost method, and he follows up with progress reports along the way to show you how successful a garden can be, even without a fall tilling.