Few crops bring more joy to Southern California gardens than tomatoes. Whether it’s a juicy heirloom, a sweet cherry variety, or a dependable Roma, tomatoes are a staple in Inland Empire backyards. But timing is everything. Planting tomatoes at the right moment ensures a strong harvest, while planting too early or too late can leave you with stunted plants or little fruit.
In the Inland Empire, the best time to plant tomatoes is in spring, after the danger of frost has passed. For most of Riverside and San Bernardino counties, this falls between mid-March and early April. At this point, the soil has warmed, and nighttime temperatures are consistently above 50°F, conditions tomatoes need to thrive. Planting earlier may be tempting during warm days in February, but cool nights can stress young plants and slow their growth.
Gardeners in Zone 9 can start seeds indoors as early as late January, giving seedlings a head start before transplanting outdoors in March. For Zone 10, which includes warmer inland areas closer to Palm Springs, transplanting can sometimes begin earlier, provided nighttime temperatures stay mild. Using protective covers, such as row tunnels or frost cloth, can extend your planting window if spring nights remain chilly…