You've heard about Epsom salt, rock salt, copper nails, bleach, and motor oil. Some of these work. Some are myths. Here's the honest breakdown of every stump-killing method—and whether it's worth your time.

First: Why Kill a Stump?

Killing a stump stops it from sprouting suckers and speeds up natural decomposition. A live stump can send up dozens of shoots and takes much longer to rot. A dead stump decomposes in 3–7 years on its own.

Methods That Actually Work

1. Chemical Stump Killer (Potassium Nitrate)

Effectiveness: High | Timeline: 4–8 weeks to kill, 1–2 years to decompose

Products like Spectracide Stump Remover use potassium nitrate, which accelerates wood decomposition. Drill holes in the stump, pour in the granules, add water. The stump becomes spongy within 4–6 weeks and can be broken apart with an axe. This is the most effective non-mechanical method.

2. Triclopyr Herbicide

Effectiveness: High | Timeline: 2–4 weeks to kill, 2–5 years to decompose

Applied to the freshly cut stump surface or drilled holes, triclopyr (found in products like Ortho Groundclear or Brush-B-Gon) kills the root system effectively. Apply immediately after cutting for best results. Excellent for species prone to resprouting (Bradford pear, black locust, tree of heaven).

3. Covering/Smothering

Effectiveness: Moderate | Timeline: 1–3 years

Cover the stump with a black tarp or dark plastic secured tightly. No light = no photosynthesis from any sprouts. Combined with chemical treatment, this accelerates killing and decomposition. Works but takes time.

Methods That Are Mostly Myths

Epsom Salt

Effectiveness: Low | Why people believe it: It's "natural"

Magnesium sulfate (Epsom salt) can desiccate a stump over time if applied in very high concentrations, but requires repeated application for 6+ months and doesn't kill deep roots. You'd need to drill dozens of holes and fill them weekly. It's not worth it versus proper herbicides.

Copper Nails

Effectiveness: Negligible | Why people believe it: It's old lore

The idea that copper is toxic to trees is real, but the amount of copper from a few nails is far too small to harm a living tree or stump. This is a persistent myth with no meaningful effect.

Rock Salt (Sodium Chloride)

Effectiveness: Moderate, but damaging | Caution: Damages soil and nearby plants

Salt will eventually kill a stump, but it also sterilizes the soil around it, kills nearby grass and plants, and can leach into the water table. Don't use it.

Bleach / Motor Oil

Effectiveness: Minimal | Environmental concern: Yes

Neither effectively kills a stump and both contaminate soil. Avoid.

The Honest Bottom Line

None of these methods replace stump grinding for speed and cleanliness. Chemical treatment is useful if you want to stop regrowth after grinding, or if you have a small stump in an area where you can wait 1–2 years for decomposition. For most homeowners who want the stump gone, grinding is faster, cleaner, and often cheaper than years of DIY treatment.