Give your houseplants the dregs of your coffee. There’s plenty of nitrogen in this, so dilute your black coffee with a little bit more water and apply it to the soil to give it a nitrogen boost.
Bear in mind that they won’t enjoy this every day, and it should only be added if there’s no milk or sugar. So, don’t go giving your houseplants a sweet latte!
Although this can be don every once in a while, I still recommend using a proper houseplant feed such as Miracle Gro’s Pump & Feed.