Is coffee good for watering plants?
…but dilute it first with 3 parts water. You want it to look like weak black tea. Coffee and coffee grounds contain nitrogen which makes plants grow, stay green and healthy. It also contains Calcium and Magnesium. Theses 2 minerals are very beneficial to plants. Coffee is very similar to compost tea in that its rich in nutrients and minerals. And it will make your plants grow like crazy!
So if you’re about to dump out that last bit of coffee from your cup…DON’T. Water it down and pour it on your plants, indoors and out.