After brewing coffee, let the grounds cool slightly.
Sprinkle the damp grounds in a thin line around entry points, windowsills, baseboards, or anywhere ants are gathering.
Replace the grounds every 1–2 days, especially if they dry out or start to develop mold.
Notes
Extra Tip: Used coffee grounds can also be sprinkled in garden beds or outdoor planters to help deter ants before they make it inside. Just avoid over-applying, as too much acidity can affect certain plants.