Flowers & crops made for the shade

Many food crops thrive only when they are bathed in sunlight most of the day. Most of the “summer crops,” such as tomatoes, corn, beans, squash or cucumbers, need a minimum of six hours of sun a day.

Other crops, those we grow for leaves or roots, such as lettuce, kale, cabbage or carrots, can be grown where sunlight will strike them as few as four hours a day. A number of our favorite herbs and edible flowers also want half to fullday sun.

Shade often limits the part of the garden where an urban gardener can grow food crops. There are buildings, fences, trees all around. What’s a food gardener to do? Because my backyard is half shady in fall and spring and completely shady in winter, I can offer some advice.

Is part of your garden under a dense tree? That’s heavy shade. Most food plants will not thrive there, but it’s a great place for a compost bin — not too close to the tree, though. A “hot” pile will heat from the compost bacteria so it does not need the sun. Worm bins are fine in the shade as well. Any kind of bin will be easier to keep moist if it’s out of bright sunlight.

A thin, open tree or an overhead arbor will make dappled or light shade. A third kind of

Moon shadow

To see what parts of your garden will be in shade in winter, go out late on a clear night, on or near a summer full moon. Whatever part of your garden lies in shadow under the full moon in midsummer is the part that will be in shadow in the daytime in midwinter. The next full moon is Tuesday, July 16. The sun was highest on June 21, the day shadows were shortest. The longest daytime shadows are on Dec. 21. Moon shadows are the opposite — long in summer, short in winter.

July talk

Pam Peirce will discuss year-round food gardening 12:30-2:30 p.m. Saturday, July 20, at the Sunset branch of the San Francisco public library, 1305 18th Ave. The talk is free.

shade, common in cities, is “open shade” made by a house or fence on one side, but with open sky above.

A “full sun” plant wants the leastshaded place you have, whatever your microclimate; but don’t worry, the term “full sun” always assumes there will be some foggy or cloudy days. However, temperature matters. The common suggestion “partshade inland, full sun at the coast” recognizes that coastal sunlight is generally cooler, and plants that could not take full sun in a hot place can do so in a cooler microclimate. Inland, dappled or lightly shady areas offer an environment a bit cooler than in full sun. This is some help in growing leafy crops, such as lettuce or kale, longer into spring, or starting them a bit earlier in the fall.

Throughout our region, some crops grow well in open shade, even in winter. What they have in common is that they’re coolpreferring leafy plants and include parsley (flat or curled), arugula (rustic or regular) and chervil. Other leafy greens, such as lettuce, kale, collards, mustard or chard, may be a bit smaller in open shade but are worth a try.

Chervil, by the way, is a coolseason annual herb. Sow its seed in fall for a winter crop. In flavor, chervil is a cross between parsley and anise. French cooks enjoy its lacy leaves chopped into an omelet, added at the end of cooking.

The edible flower calendula grows well in open shade. Also, if violas are already in bloom when lengthening fall shadows overtake them, they will continue to bloom in shade.

In addition to the above, here are three herbs that do doubleduty as edibles and ornamentals in various amounts of shade: Mitsuba (Cryptotaenia japonica) is a perennial herb/ vegetable also known as Japanese parsley. It lends its celerylike flavor to soups and salads. It’s happiest with dappled shade yearround, but in an oftenfoggy microclimate it can be OK if it gets sun part of the day. A toosunny location causes its leaves to yellow. This attractive perennial plant, 1½ to 2 feet tall and about 1½ feet wide, can be grown from seed, best sown in early spring or when weather cools in late summer. Cut the flower stems out for better leaf production. Can be grown in a 12 to 14inch pot. Sweet woodruff (Gallium odoratum) is a low ground cover with culinary uses that thrives in dappled or open shade. It grows 4 to 8 inches tall with whorls of narrow leaves; winsome white flowers appear in late spring. When the leaves have been dried, they release a vanillalike scent. They can be used to infuse flavor into white wine or apple cider (this takes a couple of weeks; refrigerate the cider), or to brew a tea. The dried leaves are also used in sachets. Start with a plant in fall or spring. Finally, our California native yerba buena (Satureja douglassii) prefers part shade but not deep shade; in the wild it thrives in small clearings in the woods. In late spring, its short, trailing branches bear small white flowers. Many enjoy its minty/limey flavor as a brewed tea. And it’s worth growing just for the talking point that it’s the plant from which the city of San Francisco got its earliest name. Start with a plant in fall or early spring.

As with any food crop, to conserve water limit the area in which you grow these plants and amend the soil with organic matter.

Pam Peirce is the author of “Golden Gate Gardening.” Visit her website, www.pampeirce.com Email: food@sfchronicle.com

Pam Peirce Violas are edible flowers, and once in bloom they will continue to bear flowers even as shadows put them into open shade.