Beneath an archway of pale-pink wild roses, the weather-worn gate of the San Geronimo Valley Community Garden opens onto terraced rows of raised beds and wood-chipped, winding pathways. Summer heat beats down on the dry grasses of the hillside, but within the woven-wire fence, boxes brim with dark leafy greens, tall scallions, and sprawling squash vines. Deep purple tomatillos hang like delicate lanterns beside thick tangles of tomatoes. White trumpet lilies, spires of orange snapdragons,…