A lot of my cool season seedling packets tell me to “Plant as soon as the soil can be worked in spring” without any further instruction.
Obviously, I’m not going to dig in frozen or snow-covered ground. But otherwise, as soon as it’s thawed, is it good to go?
Definitely not, according to the garden resources I checked. Soil that is too wet from melting snow and spring rains will compact easily when you walk on it. Dig into it with all of the energy of a New Englander who’s been cooped up all winter and your soil will break up into an uneven mess of clumps and air pockets.
Compacted soil. Clumpy soil. They don’t even sound good, and in fact, both are bad environments for your seedlings and transplants. Ideally, your soil should contain about 50% open pore space–that’s 25% water and 25% air. Luckily, no one is expecting you to measure the pore space; I’m only mentioning it to help demonstrate what can happen if you mess too much with your soil structure. Working your soil, especially when it’s too wet will alter the pore spaces, affecting water and air movement and how well all of the seeds you planted will develop roots and emerge as seedlings.
What’s the right moisture level for working the soil? Information on Rodale’s website suggests that if you can squeeze your soil into a ball that can be easily shattered by pressing into it with your finger or dropping it from a height of three feet, you should be okay. On April 1 of this year, I felt okay about prepping my bed at Perkins Park; the next day when it snowed was a different condition altogether. The point is, conditions can change from day-to-day.
Let’s say your garden’s moisture level is ideal for prepping it for planting. Time to get out the shovels and pitchforks and hoes and rototillers? Hold on…the more I’ve been reading and learning about soil, the more convinced I am that the less you work your soil, the better. Here is one case where laziness–no more back-breaking double digging–might be better for the long-term health of your garden.
Tom Akin, agronomist and State Resource Conservationist at the USDA’s Natural Resources Conservation Service in Amherst, MA promotes a minimal tillage approach to growing. I heard Mr. Akin speak last fall at an Urban Gardening course I was taking through the Trustees. Tillage alters your soil structure even under ideal moisture conditions– not just on top, where you’re digging, but deeper below, too. Soil that’s been heavily tilled tends to have compacted layers below the depth of the tilled space.
Also, disturbing the soil brings dormant weed seeds to the top where they’ll germinate and compete with your garden plants until you pull them out. AND, the more you dig around in the soil, the more you disrupt all of the beneficial living organisms in your soil–not just the obvious ones like earthworms, but also bacteria and fungi.
Now, having said all of that, some crops with fine seeds grow better in soil that’s been more finely loosened. Carrots and lettuce, for example, benefit from a fine bed. Hand-tilling is better. Do the least amount of digging necessary.
Bottom line, what’s the best spring treatment for your soil and you?
- Be kind to the pores in your soil. Check your soil’s moisture before you do anything in your garden. Hold off if it’s too wet, no matter how much you want to get in there. Organize the tools in the shed instead.
- Give the back-breaking, labor-intensive approach to garden bed prep a rest. Think less CrossFit and more meditation, if you like. Dig only as necessary.
- Consider getting your soil tested if you’re new to a space or haven’t had it done in a few years.