You’ve probably seen a plant watered with an upside-down water bottle. This centuries-old watering method is surprisingly effective at getting your plants hydrated. Here’s how it works: fill up an empty water bottle (or any other small container) with water and place it upside down. Put the bottle in the plant and turn it so that the root system is fully attached to the water supply. Let the plant soak up as much moisture as it can before turning it back over to its original position. The upside-down water bottle method is easy to do for plant hydration.