Making bad soil better: Decompacting and composting

November 29, 2016
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Montgomery County residents are fortunate to have a fair amount of natural resources right in their own backyard. Great soil, however, is not always one of them.

Heavy clay content in the region’s soil can make it difficult for plants to thrive. This is particularly true when the soil compacts, squeezing out vital spaces where seeds take root, or where nutrients can filter down to the roots of existing plants.

“We have a lot of clay soil in this area and it compacts to the same level as concrete,” said Sharon Bradley, a landscape architect and principal with Bradley Site Design, based in Washington. “Roots need air and water, and when soil is compacted it eliminates air voids between the soil particles where air and water can trickle in. So if the soil is compacted it takes all that away.”


What to do with compacted soil

Growing plants in this soil is certainly still possible, but loosening or decompacting that soil is an important way to improve growing conditions for plants. It’s especially important for rain gardens and other special plantings that rely on soil to help absorb stormwater before it carries pollution to local waterways.

Adding compost can be a good way to create new, higher-quality soil. Taking advantage of these two processes is just a matter of knowing the right tool for each job, doing it the right way, and knowing when and where to go for help.


How to Decompact Your Soil

Even when plants do establish themselves, stunted growth means the soil is compacted. Not sure if your soil is compacted? There’s an easy way to test.

“Can you get a shovel in the ground? If not, it’s compacted,” Bradley said. “If you need a pick to plant, that’s not a good sign.”

Here are some rules of thumb from Bradley on how to effectively decompact soil:

  • Till soil so it’s loose to a certain depth. Two feet down is ideal for trees, 18 inches for shrubs, 8-12 inches for perennials and ornamental grasses, and 4-6 inches for lawns.
  • When you till, try to dig laterally, in addition to simply up and down
  • A professional can do some or all of a tilling job, but it’s also possible to do it yourself if you are physically up to the task. A small roto-tiller is often enough to get the job done. Hand augers can work, but “you also want to add width, not just depth,” Bradley advised.
  • It’s not too late to get started on decompacting.  Early spring and fall are the best times, however, and “the earlier the better,” Bradley said. The best time to decompact is before you plant your shrubs and perennials.

Yard trim composting

Yard trim composting

Adding Compost to Your Soil

Composting is a huge help in creating fresh layers of fertile soil. You can create your own compost, but according to Bradley, “You can’t just throw rotting vegetables on the ground.” For the unseasoned composter, buying mature compost may be the way to go.

Different types of compost

Different types of compost (Image by UMD Extension)

  • For DIYers, Montgomery County has its own composting program, which is free to all county residents and business. Pick up a yard trim composting bin at one of 13 pickup locations around the county, then get started composting leaves and other yard trim. The County offers instructions on what and how to compost.
  • Another option are private services that pick up compost and return soil to your door. One local provider is Compost Cab, a self-described “urban composting” service. For $32 a month, the service picks up a resident’s organic materials. After six months, users are eligible to receive soil. All users have to do is discard their eligible waste in the collection bins provided by the company, leave it on the curb, and let the service do the rest.
  • For those who don’t have the space or ability to compost, you can head to your local home improvement store to pick up a bag of compost.  Leafgro compost is made from the leaves collected in the county during the fall.


To start, mix the compost into your soil at a rate of 1” depth compost to 9” depth soil.  It takes 8 cubic feet of compost to cover a 100 square foot garden to a depth of one inch.  There are 2 cubic feet of compost per bag at the store, so that would be 4 bags of compost.

“This actually saves on maintenance, because you’ll have healthier soil and healthier plants,” Bradley said. “You won’t have to worry as much about how your plants are doing because they’ll be strong.”



By Scott Harris.  Scott is a freelance writer who lives in Montgomery County and covers the environment and other topics. Scott may be reached at


Graphic of the RainScapes LogoThe RainScapes program offers technical guidance and financial rebates to Montgomery County residents and businesses who install rain gardens and other special projects to help prevent stormwater runoff in our local environment. For more information, visit the RainScapes website.


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