The makeup of home-grown salads changes by the season.
From March through May, cool-season greens thrive. Lettuce, spinach, bok choy and mesclun mixes all prefer cooler temperatures with a bit of rain thrown in, and they tolerate light frosts.
By early June, temperatures are on the rise, the daylight hours are long and many traditional salad greens just can't grow anymore. While most lettuce varieties can't stand the heat, a few tolerate hot weather and, with a little extra care, will produce through summer and provide partners for cucumbers and tomatoes.
Another cool-season green that hates summer is spinach, but the alternative is New Zealand spinach, also called Malabar spinach, which provides a ground cover of edible greens. When steamed, it tastes just like spinach and works great for stir-frys. Unfortunately, it does not have the spinach taste when eaten raw and has a slight bitterness to it.
Two lettuce varieties that tolerate Rogue Valley summers include an old-time heirloom and a newcomer to the garden. Deer-tongue lettuce has been passed down for generations as the perfect summer lettuce. It tolerates heat, is slow to bolt and has a growth habit similar to Bibb lettuce, but with pointed leaves. It is available in both red- and green-leafed varieties.
Jericho lettuce is a Romaine type developed in Israel that has great heat tolerance and is extremely slow to bolt. Territorial Seed Co. in Cottage Grove sells both types of lettuce seed. Sow them directly in the soil and thin to 4 inches apart in a row.
Malabar spinach grows low as a ground cover and can easily spread 5 to 6 feet over a season. End tips are harvested, and growth is stimulated by regular harvesting. Virtually pest-free, it performs well into midfall, tolerates full sun and thrives when the soil and air have warmed and adequate moisture is furnished. The large seeds can be sown directly in warm soil.
As a safeguard against weather extremes, lettuce crops can benefit from a little temporary shade when triple-digit temperatures are hovering. A raised bed can be turned into a shaded bed by creating a hoop frame out of PVC pipes and covering it with shade cloth.
Use 3/4-inch pipe cut into 10-foot lengths. Drive an 18-inch length of half-inch rebar into the ground along each side of the bed at 4-foot intervals. Place the ends of the PVC over the rebar to create a hoop approximately 36 inches high on a 4-foot-wide raised bed.
Secure the shade cloth with garden clips that fit securely over the PVC. This structure also can be used in spring and late fall if covered with sheets of clear plastic, creating a miniature greenhouse that protects against freezes and excessive precipitation.
David James has been writing about gardening in Southern Oregon for 35 years. Reach him at firstname.lastname@example.org.