What exactly is a tomatillo? Sometimes called “husk-tomatoes” because of the papery calyx surrounding the fruit, Physalis philadelphica – also known as Physalis ixocarpa – is a member of the Nightshade, or Solanaceae, family. Members of this family include other New World favorites such as peppers, tomatoes, potatoes, and tobacco. Tomatillos are more closely related to peppers than to tomatoes and potatoes, and more distantly related to tobacco.
Photo: Frank Vincentz, CC BY-SA 3.0, via Wikimedia Commons
But really, tomatillos are just…tomatillos, tart and with a unique, lively flavor reminiscent of citrus and green apples. They’re fantastic raw or cooked and taste great with meat, garlic, onions, chilis, and cilantro. Best of all, they’re easy to grow in the home garden.
Tomatillo Varieties
Tomatillos were domesticated in Mexico and Central America long before European contact, so it’s not surprising that there are many cultivated varieties. Your favorite seed catalog(s) will have even more cultivars.
De Milpa: Strongly flavored, common in Mexican cuisine
Tamayo: Green, very large fruit
Purple de Milpa: Sweeter than the green version
Rendidora: An “improved” variety developed in Mexico with upright growth habit
Ground cherry: A different species, P. pruinosa.; tiny, sweet, yellow-orange fruit
Photo: Pen Waggener, CC BY 2.0, via Wikimedia Commons
Starting from Seed
Tomatillos don’t self-pollinate, so start enough seeds for at least two plants in the garden. The two plants don’t have to be different varieties.
Sow seeds indoors about eight weeks before planting (see below). Incubate at 80°F until germination, then adjust the temperature to 65-70°F. Seedlings will grow best with lots of light; for example, cool-white fluorescent lights placed a couple inches above the plant tops and turned on for 16 hours per day works well.
Keep the growing media moist, but not saturated. A fan directed at the seedlings helps prevent fungal diseases by keeping stems and leaves dry; it will also encourage stronger growth by mechanically stimulating the plants. If they become root-bound or crowded, transplant into larger containers.
Two weeks before planting in the garden, “harden off” tomatillo plants by gradually introducing them to an outdoor environment. Put them outside in a warm spot with partial sunlight for a couple hours per day at first, increasing the length of exposure each day by about an hour. If a cold snap, heavy rain, or high winds are predicted, keep the plants inside.
It’s absolutely fine to buy seedlings instead, but they should be hardened off also, so they are ready for the garden. Remember to buy at least two plants to ensure plenty of pollination
Site Preparation
Make use of indoor growing time by preparing the planting location. Choose a spot with 6-8 hours of sun per day. Lay out north-south rows, and don’t put tomatillos where taller plants will block the sun. If possible, plant in soil where members of the Solanaceae family haven’t been grown for 2 or 3 years to reduce the chance of disease. Remove weeds and plant debris from previous years, which can harbor over-wintering insects. Finally, tomatillos need plenty of room, so leave 2-3 ft between each plant. (‘Rendidora’ plants can be spaced by as little as 16”.)
If you haven’t had your garden soil tested in a few years, you may want to do that to ensure that soil pH and nutrients are suitable for vigorous plants. Tomatillos grow best in acidic to slightly alkaline soil, pH 5.5 – 7.3. The Virginia Tech soil testing lab will provide amendment recommendations along with test results.
Ensure that soil has adequate drainage because tomatillos grow best in well-drained soils. North Carolina State University has a nice description of an easy “percolation test” to measure soil drainage. If soil drains too slowly or too quickly, the solution is the same: add organic matter, such as compost. A good rule of thumb: incorporate 4 inches of compost into the top 12 inches of soil.
Transplanting and Cultivation
Don’t rush to plant your tomatillos outside. Being tropical plants, cold temperatures may damage tomatillos. Wait for garden transplanting until soil temperatures reach 60°F and the danger of frost is low.
When the time is right, dig holes a little wider than the plant root balls. Tomatillos grow roots from their stems – just like tomatoes – so make holes deep enough for the bottom set of leaves to be just above ground level. Loosen the root balls and place plants in their holes. Backfill, then water thoroughly.
Photo: Frank Vincentz, CC BY-SA 3.0, via Wikimedia Commons
To avoid diseases, support tomatillo plants to keep them off the ground. Tomatillos branch more than tomatoes, so a central stake is not sufficient. I’ve had good results by putting stakes in a square with 2-3 ft sides, centered on the plant, then passing twine around and diagonally across the square. I add another layer of twine every 12 inches or so as plants grow, but it’s not necessary to tie the plants to the twine.
I’ve found that tomatillos need aggressive pruning to control their spread and support vigorous fruit production. Early in the season I leave the plants alone. After several weeks (late June in Virginia) I begin cutting the “suckers,” secondary stems that grow out of the “axils,” the stem-leaf junctions where flowers appear (see picture). This ensures that I don’t get too many immature flowers at the end of the season (i.e., first frost). Don’t worry, the plants will still make plenty of flowers and fruit.
Otherwise, treat tomatillo plants like tomatoes. They need about 1½ inches of water per week; this works out to just under one gallon per square foot. Use mulch, such as straw or grass clippings, to preserve moisture and prevent weeds.
Diseases and Insect Pests
Photo: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org
Tomatillos are relatively disease-free. Once disease sets in, though, it usually cannot be cured. Prevent disease with crop rotation, support and pruning (to allow airflow and keep things dry), good sanitation practices (clean tools and clean-up), and insect control (to prevent pathogen spread). Preventative fungicide application may help, as detailed in the Virginia Cooperative Extension’s 2022 Pest Management Guide for Home Grounds and Animals (PDF). Refer to the “tomato” section.
If a tomatillo plant shows signs of disease, the diseased parts should be removed as quickly as possible to prevent spread. Dispose by burning, burying, or bagging for household trash pick-up.
| Name | Signs and symptoms | Prevention and control |
For more details about the following insect pests, consult the Virginia Cooperative Extension’s 2022 Pest Management Guide for Home Grounds and Animals (PDF). Refer to the “tomato” section.
| Name | Signs and symptoms | Prevention and control |
Photo: Whitney Cranshaw, Colorado State University, Bugwood.org
Harvest
Harvest after the fruit has grown to fill the husk, and the husk has turned brown. The husk may tear and expose the fruit. This is useful for purple varieties, which are green until they ripen. Ripe fruit will be firm, but not hard. Overly ripe fruit will be soft and tasteless (green tomatillos will turn yellow). Fruit may fall off the vines before it’s fully ripe, but will ripen if stored at room temperature. Ground cherries, however, will fall off the vine when they are ripe (and sweet).
Storage, Preparation, and Cooking
Store fruit with husks attached. Tomatillos will keep for at least two weeks in a paper bag in the refrigerator. For longer storage, remove husks, wash fruit to remove the sticky residue, and freeze. To prep for cooking, remove husks and wash off the sticky residue.
Photo: HuriAguilar, CC BY-SA 3.0, via Wikimedia Commons
There are many ways to use tomatillos. Some of my favorites include: salsa verde with cilantro, garlic, and onions; chicken-tomatillo stew; tomatillo-corn soup; and savory tomatillo pie. Enjoy your tasty tomatillos!
References and Online Resources
Featured photo attribution: © Tomas Castelazo, www.tomascastelazo.com / Wikimedia Commons / CC BY-SA 4.0
Grow your own tomatoes and tomatillos Oregon State University Extension Service
Growing tomatillos Texas A&M Agrilife Extension
Growing tomatillos and ground cherries in the home garden Minnesota State Extension
Off the beaten path: Ground cherries Penn State Extension
A phylogenetic framework for evolutionary study of the nightshades (Solanaceae): a dated 1000-tip tree Särkinen et al. (2013) BMC Evolutionary Biology 13, article no. 214
Tomatillo, husk-tomato Purdue University Center for New Crops and Plant Products
Tomatillos (PDF) Iowa State University Extension and Outreach
Tomatillos in the garden Utah State University Yard and Garden Extension
