Down to Earth

Soil-building is a marathon, not a sprint.

Story by Josh Volk

Building good soil is a long-term proposition, not something that happens at the beginning of every season before you plant your seeds. Soil-building takes years. Adding soil amendments like lime, feather meal, and compost can speed up the soil-building process, but soil can only absorb so much at once, so don’t push it too fast or you’ll do more harm than good — like running too fast at the start of a marathon instead of pacing yourself.

Yes, you can buy soil, but in almost every case, it’s not necessary. Are plants growing in the current soil – even if it’s just weeds? If so, that’s a good indicator that you have something to work with.

Test soil for plant nutrients

Taking a soil sample is a simple and relatively inexpensive way to get crucial information. Take a sample once a year, at the same time every year, and send it to a lab to get it tested. The cost is about $35, depending on the lab and the exact test. I recommend a complete soil-nutrients test. The first year, you’ll get recommendations for what amendments to add (ask for organic recommendations for mixed vegetables unless you have something else in mind). In subsequent years, you can see if what you did improved the soil. 

I’ve used A&L Western Laboratories for many years, but there are many other labs out there and plenty of resources for how to take the sample and how to read the results. Use the same lab every year to make sure you’re comparing apples to apples when looking at your soil test.

Note: There are also soil tests to identify soil type and contaminants. Knowing the soil type isn’t critical, and for contaminant testing, you need to know what you’re looking for, as these tests are quite a bit more expensive and are specific to each potential contaminant. In urban gardens, a lead test is the most common contaminant test, but knowing the history of your garden soil is the best indicator of what to test for. 

Weeds make the best compost

Weeds are incredible scavengers of soil nutrients, water, and sunlight, and that’s what makes them so tenacious in your garden beds. It’s also what makes them a logical base for making your own compost. A simple heap of weeds practically composts itself if left to sit for a few months. Whenever I weed in the garden, I rake up all the weeds and toss them on the compost pile, along with a little garden soil and whatever food scraps I have. Six months to a year later, I have beautiful compost to spread back in the garden, and anything that was too big to break down the first time just goes back into the new pile to inoculate it.

Soil moisture is key

Trouble digging? Almost any soil will feel too compacted to dig if the soil moisture level isn’t right, and you’ll do as much damage as good by working the soil when it’s too dry or too wet. If you can make a walnut-sized ball of soil that holds together but cracks apart easily when dropped, the soil is probably at a good moisture level for working. 

Improve soil with compost and roots

After rain, or irrigation, different soil types act differently. Clay soil needs more time to dry out after rain or irrigation and has a narrower window of time for working before it becomes too dry. Sandier soil can dry out very quickly and has a wider window. Increasing organic matter over time by adding compost, and continuously growing plants so that their roots can help open up the soil — while at the same time holding it together — are the best ways to increase the window of time when the soil moisture is just right in any mineral soil.


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