A gopher probe is a simple rod you push into the ground to locate pocket gopher tunnels hidden below the surface. Finding those tunnels is the critical first step in any gopher control effort, whether you plan to set traps or apply bait. The probe works by feel: as you push it through soil, you’ll notice a sudden drop in resistance when the tip breaks through into an open tunnel, typically 4 to 12 inches deep.
What a Gopher Probe Looks Like
At its simplest, a gopher probe is a solid metal rod about 1/4 inch in diameter and long enough to reach at least 12 inches into the ground while leaving plenty of handle above the surface. The key design feature is an enlarged tip, slightly wider than the shaft, which makes it easier to feel the distinct “drop” when you hit an open tunnel. Without that wider tip, the probe can slide into dense soil pockets and give you false readings.
You can buy commercial probes or make your own from a metal rod or even PVC pipe. A piece of rebar works in a pinch, though a smooth steel rod moves through soil more easily. Commercial reservoir-type probes combine the locating function with a built-in bait dispenser. These have a hollow shaft and a trigger mechanism that releases a measured dose of bait directly into the tunnel once you find it. They’re designed for people managing large areas where stopping to hand-place bait at every tunnel would take too long.
How to Read a Gopher Mound
Before you probe, you need to know what you’re looking at. Gopher mounds are crescent or fan-shaped with a visible plug of soil on one side. That plug marks where the gopher pushed dirt out of its tunnel and then sealed the opening. Mole mounds, by contrast, are volcano-shaped with a roughly circular margin and no obvious plug. If your mounds are round and symmetrical, you’re dealing with moles, and your approach will be different.
The plug is your landmark. The main tunnel runs past the mound, and its location is predictable relative to that plug. On a fan-shaped mound, the main runway is generally found 4 to 18 inches from the plug side. That’s where you’ll aim your probe.
Step-by-Step Probing Technique
Start at a fresh mound, one with dark, moist soil that indicates recent gopher activity. Locate the plug on the crescent-shaped mound. Stand on the plug side and begin probing 4 to 12 inches behind it, pushing the rod straight down into the ground.
Push slowly and steadily. You’ll feel consistent resistance as the probe passes through packed soil. When the tip enters an open tunnel, you’ll feel a distinct drop of a couple of inches as the rod suddenly moves freely. That sudden give is unmistakable once you’ve felt it a few times. The main feeding burrows sit 6 to 12 inches below the surface in most soil types, though nesting chambers can be much deeper.
If you don’t hit a tunnel on the first try, pull the probe out and try again a few inches to either side. The tunnel can curve, so working in a small arc behind the plug usually finds it within a few attempts. Harder, drier soil makes probing more physically demanding and can muffle the drop sensation, so probing after rain or irrigation, when the soil has some moisture, gives you a clearer feel.
What to Do Once You Find a Tunnel
Setting Traps
If you’re trapping, use the probe hole as a guide to dig down and open the tunnel. You’ll place traps inside the main runway facing both directions, since you won’t know which way the gopher will approach. After setting traps, cover the opening to block light, which gophers avoid.
Placing Bait by Hand
For hand baiting, enlarge the probe hole by rotating the probe back and forth. Drop a small amount of grain or pelletized bait through the opening into the tunnel. A funnel helps get the bait down cleanly. Then cover the hole with a dirt clod or small stone to keep light out and prevent loose soil from burying the bait. Place bait in two or three spots along the same tunnel system for the best results.
Using a Reservoir Probe
Reservoir-type hand probes speed up the process considerably for larger properties. Once you feel the probe drop into a tunnel, you simply pull a trigger and the device deposits a pre-measured amount of bait directly into the runway. You don’t need to withdraw the probe, enlarge the hole, or handle bait separately. One important maintenance note: check the probe tip periodically, because soil can clog the dispensing mechanism and prevent bait from releasing properly.
Tips for Better Results
Focus on the freshest mounds. Gophers constantly extend their tunnel systems and abandon older sections, so probing near old, dried-out mounds often leads to empty, collapsed tunnels. A single gopher can create dozens of mounds, so a yard full of mounds doesn’t necessarily mean a large population.
Probe on the right day. Soil that’s moderately moist from recent rain or watering is ideal. It’s easier to push the probe through, and the walls of active tunnels hold their shape better, giving you a cleaner drop when you hit one. Bone-dry summer soil or waterlogged ground both make probing harder and less reliable.
Work systematically. If you have multiple fresh mounds, probe at each one and mark the tunnel locations with small flags. This gives you a map of the active tunnel network so you can place traps or bait at several points along the same system, which dramatically improves your odds of contact with the gopher using that runway.