Best Self-Watering Planters for Patios

A self-watering patio planter keeps a reservoir under the mix, so you fill a tube instead of watering the surface every hot day. EarthBox is that kind of box. This page sums up how they work in general. It was not a hands-on test.

EarthBox Container Gardening System on Amazon

How it works

• A water reservoir sits under a platform or screen at the bottom of the planter.
• Part of the potting mix reaches down into the water and wicks moisture up to the roots.
• You refill through a fill tube. An overflow hole at the top of the reservoir lets extra water, including rain, drain out.

Why it helps on a patio

• Pots in sun and wind dry out fast, and a reservoir gives you a buffer between waterings.
• Watering through the tube keeps leaves dry and the surface from crusting.
• Thirsty crops such as tomatoes, peppers, cucumbers, and leafy greens do well with steady moisture.

What to watch for

• Use potting mix, not garden soil. Garden soil packs down and wicks poorly in a container. See soil for bagged potting mixes.
• Keep the overflow hole clear, or heavy rain can waterlog the roots.
• Check the reservoir in hot spells. It stretches the time between waterings but doesn’t remove the need.
• Mind the weight. Water weighs about 8.3 pounds per gallon, on top of wet mix. Check what a balcony can carry before placing a large planter.
• Skip plants that like to dry out, such as succulents and rosemary. Constant moisture doesn’t suit them.