Coffee grounds work well for acid-loving plants like roses, hydrangeas, azaleas, blueberries, and tomatoes, since they add a bit of nitrogen and improve soil texture. I’ve also used them around houseplants like pothos and peace lilies in small amounts, and they seemed to do fine. Just don’t overdo it too much can compact the soil or make it overly acidic, so it’s best mixed into compost or soil rather than dumped straight on top.