How to Grow and Cook Tomatillos: You Can't Do Mexican Without Them

Tomatillos (Physalis ixocarpa) are also called "ground cherry", or "husk tomato". They are a distant relative of the tomato, with a similar flower and fruit, except that the fruit is protected by a papery husk. The most common variety is the green-fruited one that becomes yellow, but occasionally you may see a variety that turns purple when ripe. These plants are essential for Mexican cooking, and a nice addition to many other recipes. They are used raw or cooked.

Growing tomatillos is easy. They will thrive in the average vegetable garden, and are easy to start from seed. They need full sun even in Arizona, well-drained soil, regular water, and some fertilization. If nurseries in your region don't sell them as started plants, seeds are available on the Internet. You must have at least two plants before they will set fruit. I always plant two or three of them because I want lots of tomatillos. They are frost-tender, but can even be grown in the long Alaskan summers with a bit of protection.

The plant is a sprawler. In Mexico they grow in the cornfields, spreading between the rows and along the fences. I use a tomato cage to try to keep the fruit off the ground and away from the quail. My experience last year was that by mid-July they had outgrown the support and the sprawling branches were firmly rooted into the ground at some of the leaf nodes. By late September my three plants were almost filling an 8 by 6-foot raised bed and overflowing a couple of feet on either side of the bed. Keep this in mind - tomatillos can overwhelm slower-growing plants.

It is not easy to tell when tomatillos are ready to harvest because you can't see inside the husks. Size is not a clue because the mature size can be grape to golf ball size. Fortunately, they are edible at any stage. They start out tart, like a green apple, and get sweeter as they grown and ripen. The best ripeness for most recipes is a light apple green, but don't worry if you find a pale yellow one. It's still good eating. I gently squeeze the husk to see how large the fruit is. If the fruit almost fills the husk, or is splitting the husk, it's ready to use.