Digging up roots effectively depends on your goal — for corn rootworm assessment, dig a 1-foot soil cube and wash the roots; for removing tree roots, trench, cut with a serrated tool or reciprocating saw, and pry out with a demolition bar.
One wrong cut can kill a tree or hit a buried utility line. Whether you’re scouting a cornfield for rootworm damage or clearing roots from a backyard planting bed, the method and the tool determine whether the job goes smoothly or turns into hours of frustrating work. Here’s how to dig up roots the right way — with the exact steps for both agricultural and residential situations.
Corn Root Dig: The Professional Method for Assessing Rootworm
The most common agricultural reason to dig up roots is checking for corn rootworm feeding damage. This process follows a five-step procedure used by agronomists and crop scouts.
Select five consecutive roots from four different areas of the field. Leave a 1-by-1-foot cube of soil around each root. Chop off the plant top and use the remaining stem as a handle for pulling. Shake off the loose soil, then dunk the root mass in a bucket of water for 2 to 5 minutes — rootworm larvae will float to the surface. Spray the roots with a hose or pressure washer to remove trapped soil. Rate the damage on the 0 to 3 node-scale (0 means no damage, 3 means three or more nodes are damaged). Look for discoloration, scarring, and channeling on the roots.
Digging Up Tree Roots: The Step-by-Step for Landscaping Jobs
Tree root removal follows a different set of rules. These steps apply whether you’re removing a single troublesome root or preparing to transplant an entire tree.
Before any digging, call 811 at least three business days before starting. Utility companies will mark gas, electric, and water lines. Stay 18 to 24 inches away from those marks depending on your state’s regulations. Calculate the tree’s Protected Root Zone (PRZ) using this formula: trunk diameter in inches measured at 4.5 feet off the ground, multiplied by 1.5 feet, multiplied by 2. Do not cut inside the PRZ.
Excavate soil around the target root. Mark where the cut will go to protect the tree’s structural and feeder roots. Cut the root with a saw, then fill the hole with dirt or organic mulch. Monitor the tree afterward for leaning, illness, or decay.
Root Digging Tool Specs: What to Look For
Using a lightweight shovel on heavy roots wastes time and energy. The table below shows the best tools matched to each situation.
| Tool Type | Best For | Key Spec |
|---|---|---|
| Serrated root shovel | Sawing through thick woody roots | High-strength steel blade, serrated edge |
| Nursery spade (all-steel) | Defining root balls for tree transplanting | Heavy all-steel construction, sharpened edge |
| Reciprocating saw (Sawzall) | Cutting underground roots in tight spaces | Pruning blade, insert blade before battery |
| Demolition bar | Prying roots out after cutting | Long steel bar for leverage |
| Radius Garden Root Slayer | Multi-purpose root cutting without extra tools | Award-winning serrated design |
| Home Depot Root Assassin (RA-003-21) | Large-scale root removal in yards | 60-inch handle, comfort grip |
| Pressure washer | Washing corn root balls after digging | Removes trapped soil without damaging roots |
When the job requires a dedicated digging tool, the right shovel is the difference between a quick extraction and a back-breaking struggle. If you’re ready to buy a serious tool for this work, check out our roundup of the best shovel for digging up roots that cuts through the market to find models that last.
Digging a Large Tree by Hand: The Transplant Method
When removing an entire tree for transplanting, timing and root ball size matter most. Start the work before spring budding, as soon as the ground thaws during the dormant season. For every 1 inch of trunk diameter measured 6 inches above ground, dig 11 inches of root ball.
Dig a trench around the tree, tapering inward as you go deeper. Use a heavy all-steel nursery spade sharpened before use to cut the roots cleanly. Work the tree up to ground level by pulling side-to-side and adding dirt underneath the root ball. Slide the tree onto a tarp or garden slide for transport. If the problem isn’t life-threatening — for example, the tree isn’t threatening a house — consider leaving it alone.
Common Root Digging Mistakes and How to Avoid Them
Most people make one of four errors that turn a root-digging job into a disaster. Failing to call 811 before digging can result in hitting live utility lines. Cutting inside the Protected Root Zone can kill the tree by destroying structural and feeder roots. Using lightweight shovels that bounce off roots wastes time — always use a heavy, all-steel tool such as a nursery spade. Cutting roots for purely aesthetic reasons without a serious structural problem damages the tree without justification.
Safety also matters when using power tools. When operating a reciprocating saw, always insert the blade before installing the battery to prevent the saw from starting accidentally if bumped.
Serrated vs. Standard Shovels: Which Digs Better?
Serrated shovels have become a popular choice for root work because their toothed edges saw through roots that a standard blade would bounce off or snap at. Standard flat-blade shovels work fine for loose soil and small roots but struggle with thick woody roots. For the toughest jobs, professional landscapers sharpen the edge of a standard spade with a grinder or file to slice through big roots cleanly. The right tool depends on root thickness and soil density.
| Blade Type | Root Thickness | Best Scenario |
|---|---|---|
| Serrated | Up to 2 inches | Sawing through roots without switching tools |
| Standard (sharpened) | Up to 1 inch | Clean slicing in softer soil |
| Nursery spade | Over 2 inches | Root ball trenching and tree transplanting |
| Reciprocating saw | Over 3 inches | Underground roots in confined spaces |
Whether you’re digging a 1-foot soil cube in a cornfield or trenching around a backyard oak, the method is straightforward once you have the right tool and safety steps in place. Start with the 811 call, know what you’re cutting and why, and pick a shovel that matches the root size.
FAQs
Can I use an axe to cut tree roots?
An axe can work on large surface roots but it is less controlled and more dangerous than a serrated shovel or reciprocating saw. The blade tends to bounce off woody roots, increasing the risk of injury. A dedicated root tool is safer and more effective.
How deep do roots typically go in a residential yard?
Most tree roots grow in the top 6 to 24 inches of soil. The majority of feeder roots are within the top 12 inches, which is why shallow trenching often hits them. Deep structural roots can go several feet down depending on the species and soil conditions.
What happens if I cut a root inside the Protected Root Zone?
Cutting inside the PRZ can destabilize the tree, interrupt nutrient and water flow, and make it vulnerable to disease or windthrow. The tree may die or lean dangerously within one to two years. Always calculate the PRZ before cutting.
Is it better to dig roots when the ground is wet or dry?
Moist soil is easier to dig because it is softer and less compacted. Very wet soil can collapse back into the trench, and dry, hard soil stresses tools and your back. The dormant season — early spring or late fall — usually provides the best balance.
How long does it take to dig up a large tree root by hand?
A single large root (3 to 4 inches thick) in average soil takes 20 to 45 minutes with a serrated shovel and a pry bar. A full tree transplant with a 24-inch root ball can take 2 to 4 hours depending on soil type and root density.
References & Sources
- Bayer Crop Science. “How to Perform a Root Dig.” Step-by-step procedures for corn rootworm assessment.
- Best Pick Reports. “A Guide to Digging Up Tree Roots.” Utility calling, PRZ calculations, and safety guidelines.
- Mike’s Backyard Nursery. “Digging a Large Tree by Hand.” Root ball ratios and dormant-season transplanting methods.
- Radius Garden. Root Slayer product page. Multi-purpose serrated root cutting shovel.
- The Home Depot. Root Assassin 60-inch shovel (RA-003-21). Specifications for consumer-grade digging tools.