My Tree Has Bad Soil – How To Improve Soil Around An Established Tree


When trees aren’t thriving in a backyard, homeowners – and even some arborists – tend to focus their attention on the cultural care the tree is getting and pest or disease issues. The vital role the soil plays in a tree’s health can easily be overlooked.
When a tree has bad soil, it cannot establish roots and grow well. That means that improving soil around trees can be the most important part of tree care. Read on for information about the effects of compacted soil around trees and tips on how to improve the soil around an established tree.
If Your Tree Has Bad Soil
A tree’s roots uptake water and nutrients that allow the tree to produce energy and grow. Most of a tree’s absorptive roots are in the topsoil, to a depth of about 12 inches (30.5 cm.). Depending on the tree species, its roots can extend far beyond the tree canopy dripline.
If a tree has bad soil, that is, soil that is not conducive to root growth, it won’t be able to function. One particular problem for urban trees is compacted soil around trees. Soil compaction has a very negative impact on the health of trees, stunting or preventing growth and leading to pest damage or diseases.
Construction work is the number one cause of soil compaction. Heavy equipment, vehicular traffic, and excessive foot traffic can press down the soil, especially when it is clay-based. In compacted clay soil, the fine soil particles get tightly packed. The dense soil structure prevents root growth and limits air and water flow.
How to Improve Soil Around an Established Tree
It is easier to avoid soil compaction from construction work than it is to correct it. Using thick, organic mulch over root zones can protect a tree from foot traffic. The thoughtful design of a worksite can direct traffic away from established trees and make sure that the root zone is not disturbed.
However, improving compacted soil around an established tree is another matter. For treatments to be effective, you have to address all of the problems that compaction causes: soil too dense to allow roots to penetrate, soil that does not hold water or allow it to enter, and poor quality soil without many nutrients.
If you are wondering how to improve the soil around an established tree, you are not alone. Many arborists have come up with techniques to treat compacted soil, but few of these are effective.
Two simple things you can do to start improving soil around trees are mulching and irrigation:
- Apply a 2- to 4-inch (5-10 cm.) layer of organic mulch a few inches (7.5 cm.) from the trunk to the drip line and reapply as necessary. The mulch immediately conserves soil moisture. Over time, mulch protects against further compaction and enriches the soil with organic matter.
- Proper amounts of irrigation are essential to a tree’s development but hard to determine when the soil is compacted. Use a moisture sensing device and an irrigation system to provide optimum moisture without the risk of excessive irrigation.
Gardening tips, videos, info and more delivered right to your inbox!
Sign up for the Gardening Know How newsletter today and receive a free download of our most popular eBook "How to Grow Delicious Tomatoes."

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.
-
8 Ideas For Decorating With Poinsettias This Holiday Season
When you’re decorating with poinsettias, consider experimenting with different varieties and fun holiday ideas.
By Mary Ellen Ellis Published
-
How To Pick A Perfectly Ripe Watermelon
Pick the the ripe watermelon from the bunch every time.
By Amy Grant Published
-
Best Trees For Carbon Sequestration And Climate Change
Let’s keep planting trees. They are our best bet for capturing carbon and may help with our global warming issues.
By Teo Spengler Published
-
6 Invasive Trees You Should Never Plant In Your Yard
What are some invasive trees you should never plant in your yard? Click here to find out.
By Teo Spengler Published
-
How Close Can You Plant A Tree To A Stump?
Looking to plant new trees near old stumps or where stumps have been removed? Click here to learn how.
By Teo Spengler Published
-
Messiest Trees That Drop Debris Everywhere
Want to know which trees will create the biggest messes in your home landscape? Click here to find out.
By Amy Grant Published
-
How To Get Rid Of Tree Sprouts In The Yard From Nearby Trees
Learn the simple way to keep pesky tree seedlings in your lawn from becoming saplings.
By Teo Spengler Published
-
7 Common Tree Care Mistakes That Kill Trees
Are you accidentally killing your tree? It's easier than you think, if you're committing one of these common mistakes. Click here for more.
By Teo Spengler Last updated
-
How To Tell How Old A Tree Is
Ever wondered how to calculate the age of a tree? Click here to learn all about it.
By Teo Spengler Last updated
-
When To Remove Tree Stakes From Saplings
A newly planted tree may grow strong when it’s staked, but don’t forget to remove the stakes when it’s stable.
By Teo Spengler Published