A couple of months ago I read Jeff Lowenfels’ Teaming with Microbes. This book describes the microbiome of soil and the various living organisms that make up a healthy garden soil. He outlines the bacteria, fungi, archaea (organisms that were first classified as bacteria but later classified as a separate group of prokaryotes in 1977 – a new class of organisms to me!), arthropods, insects, and worms that are all a part of a healthy soil system. With all of this life going on under the surface of the soil, it got me thinking about how I garden.
Like a lot of gardeners, I’ve always assumed that you needed to have a nice, soft, fluffy bed of soil in order to plant seeds and grow plants. In order to achieve this, it means using a rototiller every spring to stir up the soil in order to create this desired texture.
But Lowenfel got me wondering if this is really necessary or even beneficial. There aren’t many farmers that plow their fields like they used to in the past – they just plant directly into the soil without any preparation. So could it be that this no-till approach is something that I should consider in the garden? After exploring a lot of sites devoted to soil and rototilling, I’ve come to the conclusion that there are some pros and cons to tilling the garden.
- It can break up heavy, compacted soil.
- Large amounts of organic matter can be incorporated into the soil to improve its texture and tilth.
- Tilled soil dries out and warms up more quickly in the spring.
- If the soil’s pH needs to be adjusted, tilling distributes the lime, aluminum sulfate or sulfur throughout the soil and lead to an even adjustment of the pH.
There are also problems that tilling causes:
- Stirring up the soil disturbs communities of microorganisms as well as shredding earthworms.
- The incorporation of a lot of oxygen into the soil leads to a rapid breakdown of organic matter and the release of a lot of CO2.
- While tilling will kill surface weeds, it brings buried weed seeds to the surface where they can germinate and grow.
- Quicker drying in the spring means that there’s less water in the soil later in the season.
I had always thought that you needed to till in order to open up the soil and allow for easier water absorption and root penetration. But I now see that in a healthy soil, decaying roots, tunnels created by worms and the hypha of fungi all provide avenues to allow water to enter the soil. Also roots are strong and while they can’t break through a hard dead-pan, they can easily make their way through the average soil.
Many think that fertilizer or compost needs to be mixed into soil in order for the plant to be able to absorb the nutrients. However, this isn’t the case. The majority of feeder roots of plants are close to the surface and the natural process of leaching will bring the needed nutrients to the plants. Side dressing plants with compost or fertilizer will work well and limit the amount of wasted fertilizer.
After a lot of reading, research, and thinking, I’m moving in the direction of not tilling. This year I left a couple of beds untilled to give it a try. I find that the untilled beds have more moisture in the soil than the tilled ones. While the soil might not warm as quickly, here in south central PA, untilled soil warms quickly enough. When I planted seeds, I just used a hoe to loosen the soil a little and the seeds germinated well.
The biggest challenge to planting in untilled soil was a mental one. I’ve come to expect that garden soil should be as loose and fluffy as a bag of potting mix. It seemed a little strange to plant in soil that was more firm and dense. So far, the plants don’t seem to mind the difference so this is probably something that I need to get over!
Now don’t get me wrong – I’m not saying that I’ll never till again. If I was preparing a new site for a garden, I’d till the soil. If I planned to add a lot of compost or peat to the soil, I’d till it in. If I had pH issues, I’d rototill the lime or sulfur into the soil. And if this no-till experiment doesn’t work, I’ll certainly go back to using the rototiller.
But for now, no-till gardening seems like a good idea. It preserves the communities of life within the soil. It appears to maintain soil moisture better. And let’s face it – it’s a whole lot easier!
So, to till or not to till? The question is still open, but I’m going to see how the not-to-till option works for me.