Morning vs Afternoon Shade
When do your plants need some shelter? Typically during the hottest parts of the day – afternoons – during the hottest parts of the year – May or June through August or September. The exceptions are the areas routinely above 110°F like Phoenix, Tucson, Las Vegas, and Palm Springs – they grow better with mid to late morning shading lasting all afternoon. For the rest of us, if our plants start seeing some shadows by about 1 pm, they are comfortable and produce nicely.

What this means is that permanent overhead shade structures are usually not needed. They can be a nice addition if part of the structure is over a picnic table or BBQ area next to your garden, but the garden doesn’t always need that much cover for that long. The upside to temporary shade for part of the day is it can be removed for cool weather crops needing as much sun as possible to capture the warmth on the soil to grow earlier or later in the season.

East vs West Shade
Where is the best place for your shade? Most plants need some afternoon protection, meaning the shadows should come from the west side of your plants, or that you plant on the east side of the protection. Confused? Don’t be – think of it this way. As the sun moves to the west, it casts shadows to the east and that’s where you want your plants to be – in the shadows!

In the photo above, the Achocha is growing on the west wall of this courtyard and has afternoon protection – this photo was taken about 11 am, with full morning sun. After about 1 pm, the shadows arrive and the area cools down, even though it reaches 100°F or more each afternoon during the summer. When we first tried growing it on the east wall, it received morning protection but was baked in the afternoon’s direct sun, struggling to grow and not producing any fruits. The fruit production exploded and it was much happier once we moved it!

Southern Shade
Beyond east/west shade, you might consider giving your garden protection to the south. Shading a section of your garden along the south fence with each row having its own screening on the west side gives more sensitive plants extra protection from the sun.
Wind moderation is another advantage of shading, as each successive row slows down the prevailing breeze, making the growing conditions more favorable. Plant hardier plants upwind and less wind tolerant ones downwind.

An excerpt from “Shading Your Garden for Better Vegetables“, courtesy of Terroir Seeds.