In summer, plants in an outdoor container can suffer from hot feet as the sun beats down on the container, overheating the potting mix. But I’ve found a simple way to protect the roots of my container plants—even through the hottest months of the year here in Phoenix, where temperatures can reach 115°F.
I use containers big enough to hold more than one plant, and I make sure that one of the plants is a fast-growing hanging type, such as an asparagus fern. I plant that one on the sunniest side of the container, where it shades the side, keeping the soil cooler. If the overhanging plant grows thickly, I sometimes slip a piece of cardboard between it and the pot, which helps even more.