Underground Bait Station

Quick Answer

Underground bait stations place zinc phosphide pellets directly in the tunnel where gophers feed. Anticoagulant baits like diphacinone used to be the other option, but they’re prohibited for residential use in California now — see the legal note below. When done right, it works — zinc phosphide is lethal after a single feeding, per UC IPM. When done wrong, you poison a neighbor’s dog or a hawk that eats the carcass. Read this whole page before you touch the bait.

The Gear

• Registered underground gopher bait (zinc phosphide pellets — check the label lists pocket gophers)
• Soil probe
• Trowel or bait applicator tube
• Nitrile gloves
• Mask (for zinc phosphide — it off-gasses)
• Marker flags

The Process

1. Use a soil probe around fresh mounds to locate the main lateral tunnel — you’ll feel the probe drop 2–4 inches when it hits the void.
2. Open a small access hole with your trowel — just wide enough to insert the applicator.
3. Place the labeled dose of bait inside the tunnel, not at the entrance. Gophers are suspicious of openings.
4. Plug the hole completely with soil or a clod. UC IPM’s instruction is simply to cover the hole so light doesn’t get in.
5. Flag the location. UC IPM’s benchmark: if new mounds appear within 2 days of baiting, rebait or switch to trapping.

Bagger Pro-Tip

Diphacinone used to be a common choice for gopher bait. It’s now prohibited for residential use in California, so for a homeowner here zinc phosphide is what’s left. It’s temperamental: I’ve had it fail in damp soil, and you have to respect the off-gassing. Work slowly, follow the label, and accept that it’s a worse day than setting a trap. I also won’t use bait at all on a property where dogs are working — the risk from a bait-killed gopher is real, and no placement trick removes it.

What the Research Says

Two things from UC IPM’s pest notes matter before you buy anything. First, the anticoagulants — chlorophacinone and diphacinone — “are no longer legal for residential use in California.” That’s the whole ballgame for a homeowner here. Second, baits containing 2% zinc phosphide are available, with exemptions for home use, so that’s the one still open to you if the label lists pocket gophers. (Source: Baldwin, R.A. — UC IPM Pest Notes: Pocket Gophers, 2025)

On carcass risk the two classes differ: zinc phosphide isn’t stored in the animal’s tissue, while anticoagulants persist in the liver. Anticoagulants are the class California restricted. Don’t read that as pet-safe. Zinc phosphide is acutely toxic, and a dog that eats the bait — or a freshly killed gopher with bait still in its stomach — can be poisoned. It is the remaining legal option for a California homeowner, not a safe one. Either way, if something on your property might eat a poisoned gopher, trap instead.

Safety Warning

Keep all bait away from children and pets. Never place bait in open boxes or above ground. If a dog, cat, hawk or owl might get at the treated ground or a poisoned carcass, use traps instead. On the legal side: anticoagulant baits including diphacinone have been prohibited for residential use in California since January 1, 2024, and products labelled for the prohibited uses can only be sold to an end user by a DPR-licensed pest control dealer. Check your local regulations and read the label — it’s the legal document.

Get the Gear

The products in this category are written up on their own pages: the gopher bait I’d actually use, and how the poison options compare if you’re weighing the stronger stuff. Shop Underground Bait Applicator on Amazon →