The essential ingredient in the green salsas of Mexican cuisine is not the tomato but the tomatillo—a fruit with a citrusy, sweet flavor. Dainty paper husks encase the tomatillos, and by late summer, what seems like billions of fruits dangle from the plant's branches, ensuring that you can more than satisfy your salsa cravings by summer's end.
Native to Mexico and domesticated by the Aztecs around 800 b.c., tomatillos are one of our most ancient vegetables. Today, you can grow varieties of the same two species the Aztecs grew. Physalis ixocarpa is commonly sold in markets and has large (up to 2 ½-inch-diameter) tart green fruits, which ripen to pale yellow. P. philadelphica produces sweeter, marble-size purple fruits. This species is a common field weed in Mexico, but it is no less delicious for being a weed.
Choosing a site
Select a spot in full, hot sun, with well-drained, moderately rich soil. Tomatillos are lighter feeders than tomatoes, and while they are tough, semiwild plants, they do not fare well in soggy, poorly drained soil. Work a couple of inches of compost into the soil before planting, and fork deeply to improve drainage. Raised beds work great for tomatillos in gardens with heavy clay soil.
Start tomatillos indoors six to eight weeks before your frost-free date. Harden off indoor-started plants before transplanting outdoors. Set out at the same time you plant your tomatoes, when all danger of frost is past and the soil is thoroughly warm.
Much like their cousin the tomato, tomatillos sprout roots along their stems, so they profit from being planted deeply. The indeterminate, sprawling plants grow 3 to 4 feet tall and at least as wide, so space the plants 3 feet apart in rows 3 to 4 feet apart. Plan to give them support unless you want to pick the fruits off the ground. Two to four plants are sufficient for fresh use.