Although traditional gardening advises tilling away old roots and dead plant debris to prepare for the following year’s crops, there might be a better way to end the season. See, a few years ago, I dove into the concept of no-till gardening, and it turns out there are some compelling reasons to try a season of planting straight through last year’s crops instead of tilling them under.
When you plant through old roots in your garden, instead of removing them, you leave old fungal networks in place to continue growing and building good soil structure. The increased soil health will result in stronger crop performance the following growing season.
Time to get your hands dirty exploring why. You’ll learn about beneficial fungi and soil texture with tips straight from the pros. Then you’ll get the advice you need to plant around leftover root systems.
Three reasons you should leave old roots in the garden
Aside from saving on labor, there are a few soil-improving and back-saving benefits to leaving plant debris in the soil.
1. Dead plants add organic matter to the soil
During the growing season, your crops work hard to absorb nutrients from the soil and store them in the root system for later. If you allow those roots to stay in the ground for the next season, they will slowly decompose and release the nutrients back into the soil for new crops to absorb more efficiently.
Not only will your plants be able to capture nutrients left by last year’s roots, but your soil’s composition will slowly build up organic matter. Organic matter helps your soil hold more moisture and resist compaction, resulting in the need for less water and fertilizer.
Conserving resources while cultivating ecosystems sounds like a win-win to me!
In this video, Famer Jesse of No-Till Growers describes why he leaves as much plant debris in the soil as possible. He even shows you the math of how much organic matter you remove from the soil when you pull out old plants:
Note that the video will start a few minutes in, where he talks specifically about leaving plant roots in the ground.
2. Old roots leave behind beneficial soil fungi
Fungal networks lurk below the surface of our gardens, closely entwined with plant root systems. Although some fungi can be harmful to your garden, most of them are beneficial.
These beneficial fungi, called mycorrhizal fungi, live on plant roots in a mutually beneficial relationship. The mycorrhizal fungi improve the plant’s ability to reach and absorb nutrients and water in the soil. In return, the roots feed the fungi the sugar they create during photosynthesis.
Here’s a helpful video to see how plants and mycorrhizal fungi work together:
To help their gardens, some gardeners even buy packets of mycorrhizal fungi to innoculate their garden with at the start of the season, hoping for more robust and healthier plant growth than in previous years.
If only they knew that by leaving their old plants in the garden to break down, they could have homegrown mycorrhizal fungi right in their backyard (and save their money).
When winter rolls around, the fungi try to survive by producing spores in the soil that go dormant in the cold. The spores glean nutrients from the plant roots, storing energy like a bear does before winter hibernation.
If the roots these spores feed from are pulled out before the onset of fall and winter, then the fungal networks may not have enough time to fully prepare to overwinter, meaning that they won’t be able to survive until the following spring, leaving your garden without an established beneficial fungal system.
Instead, allow plant roots to overwinter to encourage the survival of the mycorrhizal fungal networks. Doing so will set up next year’s crop to have vigorous and healthy mycorrhiza, ensuring better water and nutrient uptake for your plants.
Not all plants can make connections with these beneficial fungi. You will want to ensure not to plant too many incompatible crops in the same space for many successive seasons, or else beneficial fungi may die out or become dormant in your garden from lack of a proper host.
Oklahoma State University gives us a list of plants that are not compatible with mycorrhizal fungi, which include,
- Brussels Sprouts
You can still plant these crops; just be sure to rotate the locations occasionally to let the soil refresh and reset.
3. Leaving old plant roots means less physical labor for you
Not removing old roots before you plant your next crop ultimately means less work.
I have spent many a season pulling up flowers, cucumbers, tomatoes, and more at the end of the season, trying to prepare a clean garden for myself. While none of those plants were difficult to pull out of the ground, the physical labor still adds up.
As a gardener, there will always be tasks that require you to get down low and bend over frequently. So use this opportunity to skip one set of laborious chores. Instead, chop the plants off at the soil level, and your job is done.
If you want to go hard-core passive in your garden this fall, leave the entire plant in the garden. Birds and bugs will come to take care of any leftover produce or flowers, and the roots will happily decompose into the soil over the winter months.
While you’re skipping the chore of clearing and tilling your garden beds, chances are you can also skip rotating your crops, especially if you’re growing flowers. Read more in this article, Do Garden Flowers Need To Be Rotated? (What You Need To Know)
How do I plant around old plant roots in the garden?
Planting your seeds or transplants into ground occupied with dead roots is a straightforward process. Here are two ways to go about it:
- Plant seedlings right through the old root systems. Make the hole a little bigger than the seedling’s rootball so you can backfill the hole with loosened soil. That will stop the seedling’s tender roots from bumping up against tougher old roots while it’s transitioning to the garden bed.
- If the old roots are particularly dense, you can shift the row or new plant hole to the side by a few inches to find looser soil.
- To direct seed in a bed where you didn’t remove the roots, you can sprinkle a half inch of fine soil on top of the bed to make a fluffy seedbed for the direct-sown crops.
All in all, leaving old roots is beneficial to your garden. It is a practice that allows good ecosystems to thrive in your garden. The benefits of beneficial fungi, improved soil texture, and less manual labor should be enough to convince you to give old roots a try.
If you want to learn more, I highly recommend checking out the No-Till Growers YouTube channel or picking up a copy of his book, The Living Soil Handbook: The No-Till Grower’s Guide to Ecological Market Gardening. Even though it’s aimed at market gardeners, the information is fascinating, and you’ll learn a lot.