Los Angeles, CA

Los Angeles zone 10b gardening operates on an inverted seasonal logic compared to most of North America. The frost-free period extends year-round, with the last spring frost recorded on 12/31 and first fall frost on 12/28, making the growing season effectively 365 days. This is not permission to garden uniformly all year. Instead, winter is the prime season for cool-season crops, leafy greens, brassicas, root vegetables, and herbs like cilantro, while summer heat becomes the limiting factor. Inland Los Angeles summers regularly exceed 85°F; coastal zones moderate slightly due to marine influence, but heat stress remains the dominant constraint for warm-season crops. The sample crops featured here succeed in Los Angeles precisely because they tolerate summer heat: figs and sweet potatoes thrive in intense sunshine and drought, peppers and eggplant sustain production through heat waves that would stall northern tomato plants in July, and rosemary and basil grow vigorously in both seasons. Water availability during the dry season (May through October) is the secondary pressure point. The real puzzle is not avoiding frost but managing heat load, soil quality in urban and disturbed areas, and supplemental irrigation demand during drought months.

Summer heat is the first barrier. Tomatoes planted as spring transplants often stop flowering when daytime temperatures exceed 90°F during peak fruit-set weeks in June and July; growers either select heat-tolerant varieties (Heatwave II, Phoenix) or accept a production dip. Drought stress compounds the problem: supplemental irrigation is essential for consistent yields, yet urban water restrictions and long dry seasons (May through October) pressure gardeners to scale back or lose crops mid-season. The absence of winter freeze also sustains year-round pest populations, spider mites, whiteflies, and scale insects never face population collapse from hard freezes, making integrated pest management a permanent commitment rather than a seasonal one. Soil in older Los Angeles neighborhoods is often compacted, depleted, or contaminated; amending with compost and mulch is non-negotiable for vegetable production.

Plant tomatoes in late February through March, not May. Transplants set fruit before the June-July heat spike that suppresses flowering. Select heat-tolerant varieties, Sungold, Early Girl, Heatwave II, and provide afternoon shade cloth in inland zones during the hottest months. Conversely, make fall your second tomato season: start seeds in July and August to have transplants ready by late September, allowing a full production cycle October through February when temperature stress is minimal. Water deeply and infrequently to encourage deep rooting and drought resilience. Drip irrigation on a timer reduces hand-watering burden during the dry season and applies water directly to roots rather than wetting foliage, lowering disease risk. Use 3 to 4 inches of mulch (straw, wood chips, compost) around vegetables to moderate soil temperature during heat spikes and retain moisture between irrigation cycles.