Even heat-hardy plants sometimes need a break from the nonstop sun. Even if you keep the soil evenly moist by using lots of soakers or drip irrigation hoses covered or cover the soil with a thick layer of mulch, many vegetables will stop producing fruit in extreme heat. For example, temperatures in the 90s cause many beans to hold back their flowers. Also, many tomatoes, peppers, and eggplants start having trouble completing the pollination process when temperatures rise above only 86°F.
Well placed shading covers are often used to help cool down your plants on those hot summer days. Shade covers can be made from old sheets, old window screens, or buy shade cloth at your garden center. You want the shade cover to be several inches above the plants to keep them from retaining heat. Construction of a shade covers is simple just tie or staple the cloth to wood stakes. If plants are too tall for a shade cover to go over the plants. Simply situate a sunscreen alongside them to shield their bases from afternoon sun.
Do not forget about those containers! Move them into the shaded part of your porch or under a large tree, or take them inside during the worst of the heat.