My soil has been turned to soup!

Asked January 13, 2016, 8:33 PM EST

I had my sewer line replaced and two major areas of my yard, where I have been carefully developing soil for the past 15 years, were dug up and then refilled during all the downpours of rain. The soil looks horrible and I fear the structure has been totally ruined and my micro organisms have been destroyed. It looks like whipped milk chocolate. What should I do? Put down a layer of straw, sand and compost and let it sit, and then add the layers again? Wait till Spring? Plant a spring cover crop of legumes? Help!

Multnomah County Oregon soil and fertility issues

1 Response

It’s difficult to respond to your question because of the unique conditions. Even so, I suggest you use a combination of techniques to repair and or/salvage what you can.

Yes, you can add compost and straw now but I suggest you not dig it in until the soil dries considerably. In fact, you could employ the so-called lasagna technique where a deep layer of organic material is applied to the surface, and then topped with compost. Come spring, you will need to decide if you can plant a garden in some of that area or if you should rely on a cover crop for the most seriously affected areas. One resource is “Lasagna, Anyone?” http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=15845

Don’t add sand. Contrary to popular wisdom, sand doesn’t improve drainage unless you add at least 60 percent, perhaps more, by volume. “The myth of soil amendments – sand” http://puyallup.wsu.edu/wp-content/uploads/sites/403/2015/03/soil-amendments-2.pdf

If you have an area you consider beyond repair, consider using raised beds which you’ve filled with a commercial planting mix commonly available where soil and bark dust is sold. See “Raised Beds” http://cru.cahe.wsu.edu/CEPublications/FS075E/FS075E.pdf and “Raised beds to try” http://extension.oregonstate.edu/gardening/six-raised-beds-try-if-you-have-bad-soil

Please let me know if you have additional questions.