Tomatillos: Salsa's Secret Soul
by David Lyon
I fumed off and on for years at my inability to make a good yellow mole sauce or enchiladas suizas -- two of my favorite Mexican dishes. I tried a dozen different chile peppers but none of them did the trick. Then, from the descriptive menu in a gringo fast-food spot in Mexico City, I learned that the missing ingredient was tomatillos! These small, hard fruits that are a bit tart, yet slightly sweet; earthy, but with a hint of citrus. In other words, like nothing else. I knew I would have to grow them if my Mexican cooking was to have truly authentic flavor. At a farm supply store in Oaxaca, I purchased seed and headed home to New England. Maybe I should have bought a Mexican gardening book, too. My gardening encyclopedia said "Grow like tomatoes." But the fruits, I soon learned, are really nothing like their very distant cousins.
I sprinkled a dozen seeds each into peat cubes in early March and was shocked when they all germinated a week later. After thinning to one plant per cube, I awkwardly transplanted the plants into the garden two weeks after my last frost date. Half the stems broke off, more of the plants bleached white from exposure to ultraviolet light, cucumber beetle larvae chomped up the leaves -- and I started harvesting tomatillos around July 4. By mid-August I couldn't get into the garden through the thicket of vines. You have to love a plant that takes that kind of abuse.
The tomatillo is a sprawling plant with heart-shaped leaves and a decidedly indeterminate habit. It's nothing if not prolific. I trialed six different kinds last summer and each bore at least 15 pounds of fruit, in a drought no less. For a plant native Central and South America, tomatillos are remarkably easy to grow in cooler climes, as my zone 6A garden attests. One gardener to whom I gave seeds had fine luck with them on the prairies of central Saskatchewan, three zones north of me. If tomatillos weren't frost-tender, they'd take over the surface of the planet.
Big Greens and Small Purples
There are two main types of tomatillos. The large green ones, about the size of a ping pong ball with a loose husk, are most common -- this is the type grown commercially in Mexico, the American Southwest and India. The plants tend to grow about three feet high and sprawl five or six feet in every direction. The fruits usually end up on the ground.
During a research trip to Mayan country in southern Mexico, I encountered the purple tomatillo as an edible weed that infests the raised cornfields of the central highlands. The fields are called milpas and the fruit is often called miltomate, or "tomato of the milpa." More compact and upright, these plants bear fruits the size of a large marble in a tight husk. As they ripen, the husk splits and the fruit turns eggplant purple. What it lacks in size, it makes up for in number -- yield (by weight) is equal to that of green tomatillos.
There are multiple variations in these two types. Some sprawl, some are upright. Some have tough skins, some tender. Acidity varies, as does the intensity of the citrus-like flavor. Some fare better in humid climates than others. Because all strains are so vigorous, almost no selection has been done and chances are, any packet of seeds will produce plants with a broad range of variations. Tomatillos are self-sterile (so always plant at least two), which is Nature's way of guaranteeing this genetic diversity.
Wilder than tomatoes
No nursery I know sells tomatillo plants, so I start my own, beginning about six weeks before the final frost. I punch drainage holes in the bottoms of the 20-ounce plastic cups, fill them three-fourths full of soilless mix and sprinkle three or four seeds on the surface. After letting the cups soak up warm (90° F) water, I barely cover the seeds with a dusting of damp mix. They germinate in less than a week at 70° . When the second set of leaves appears, I thin to the strongest plant, move the seedlings to a skylight window (55° at night, 65° by day). Like many vining crops, they sprout root hairs from the main stem, so I add soil around the growing stalks to develop a strong root system. Tomatillos aren't fussy about soil, but I always give my garden a shot of lime, rock phosphate and bonemeal when I dig in composted leaves in the spring. I then cover the tomatillo patch with black landscape fabric. Lastly I spread a layer of a quick-draining mulch such as cocoa husks to keep drooping fruits dry while they ripen. The last frost here averages May 8 -- so my tomatillos go into the garden, spaced three feet apart, with the tomatoes and peppers about May 21. The large cups encourage a deep root structure, and I plant them up to the first set of leaves. Farther south, you can also plant tomatillos directly in the garden, sowing seeds in clusters of three to four about 1/4" deep after danger of frost is past. Thin to final spacing when the plants are four to six inches tall and keep hilling up the soil around the stem as they grow. Support the young plants with large tomato cages; I thread the new branches over the cage supports as the plants grow. I feed my plants twice with Miracle-Gro for Tomatoes (5-10-10) -- at the end of June and the beginning of August. Leaf rollers, cucumber beetles, bean beetles and aphids all love tomatillo leaves, but the plants outgrow the pests. Still, a little insecticidal soap can help.Bees Love Them Too
Tomatillos bear small yellow flowers that bees love. The first round of flowers don't set fruit in my garden because bees don't get active here until late June. Tomatillos are edible at any stage but taste best when they begin to fill out or even split their papery husks -- I get my first ripe fruits in July. As they mature, they get seedier but develop a sweeter flavor for eating out of hand. They'll eventually turn yellow, drop and split, guaranteeing many volunteers next year. If kept picked, the plants keep setting new fruit until frost. They also keep growing. And growing.
Storing tomatillos is like storing onions: keep them dry in a well-ventilated spot. Hanging wire baskets in a cool pantry are ideal. The husks tend to dry out, but the fruits secrete a waxy gum that seals them from dehydration (a neat trick for a plant that develops in an area with virtually no rainfall for five months of the year). If the husks show signs of mold, remove them, rinse and dry the fruit and wrap it in paper towels to refrigerate. If you keep replacing the towels, the fruits keep up to two months.
People unfamiliar with tomatillos invariably ask what they taste like. The flavor is unique, but marries well with chile peppers, onions, garlic, or avocado (add some tomatillo puree to guacamole) and is essential to Mexican table sauces, such as salsa verde.
As Mexican cuisine continues to become more and more popular around here, tomatillo awareness has grown. One local grocery now carries tomatillos at $2.98 a pound. Neighbors walking past my garden used to ask "What are those things?" Today they look at my plants, arch an eyebrow and ask, "Tomatillos?" I think we're getting there!
THE WIDE WORLD OF PHYSALIS
The tomatillo is just one species in the large genus Physalis. These members of the tomato family (Solanaceae) are distinguished by the papery husk surrounding their fruits, The edible types are excellent in sauces, preserves and pies; the sweeter varieties can also be eaten out of hand or dried like raisins. Others are grown as ornamentals. Ground cherry and husk tomato are the most often used common names for the edible ones, but there are other common names as well, sometimes used interchangeably! Here's a guide to the most frequently grown species.
Physalis ixocarpa -- tomatillo, tomate verde, Mexican husk tomato, jamberry -- Three- to four-foot tall annual native to Central and South America. Toma Verde and Purple de Milpa are strains commonly carried in seed catalogs, or you may just find a generic listing for a "tomatillo." Physalis philadelphica, which inludes the Tarahumara, Tepehuan and Zuni tomatillos, are smaller, wild or semi-cultivated types, collected from remote areas or Indian tribes in Mexico.
Physalis pruinosa -- ground cherry, husk tomato, strawberry tomato, dwarf Cape gooseberry -- A one- to two-foot-tall spreading annual with grayish fuzzy leaves, native to eastern North America. This is the common edible husk tomato grown in gardens. The cherry-sized fruits are borne low to the ground. They ripen from green to yellow gold, dropping to the ground when mature.
Goldie is a popular variety that bears 3/4" sweet apricot-colored berries
Cossack Pineapple is an Eastern European relative that has bite-sized yellow fruits with a faint pineapple flavor.
Physalis peruviana (P. edulis) -- Cape gooseberry, goldenberry, poha, ground cherry, winter cherry, strawberry tomato, gooseberry tomato -- A 1 1/2- to three-foot-tall perennial native to the Andes that bears bright yellow marble-sized edible fruits. Golden Berry is a larger (one-inch-diameter) strain with a pineapple-strawberry flavor.
Physalis heterophylla -- downy ground cherry, clammy ground cherry -- A three-foot-tall perennial native to Eastern North America with small yellow edible fruits.
Physalis franchetii (P. alkekengi) -- Chinese lantern, Japanese lantern, winter cherry, strawberry tomato -- A one- to two-foot-tall perennial, sometimes grown as an annual, that's native from southeast Europe to Japan. This ornamental species bears orange seed cases resembling brightly lit paper lanterns that can be dried and used as everlastings. Very hardy, Chinese lanterns spread by underground roots and can become invasive.
Tomatillos in the Kitchen