Tomatillos are ready to harvest when the papery husk surrounding the fruit turns from green to tan and begins to split; the fruit itself will be bright green, purple, or yellow depending on the variety.
A mature tomatillo will be the size of a cherry tomato or slightly larger. Smaller fruit is often sweeter than larger fruit.
Tomatillos are ready to harvest 75 to 100 days after sowing, 65 to 85 days from transplanting. Plants bear fruit for 1 to 2 months or until the first frost. Pick fruit at 7- to 14-day intervals to keep the plant producing. One tomatillo plant can produce 60 to 200 fruits in a growing season, about 2½ pounds per plant.
Tomatillos will be past ripe when the gloss of the fruit dulls.
Harvest tomatillos by giving fruits a light twist or snipping them from the plant with a garden pruner or scissors. Peel back a small part of the husk, the fruit should be nearly blemish free. If the fruit is sticky when you remove the husk just wash it with mild soapy water.
Tomatillos are best used fresh and green. They are less juicy and more richly flavored than a tomato. Raw tomatillos have a zesty, tart flavor that develops an herbal lemon flavor when cooked.
Store tomatillos in their husks for about two weeks in a paper bag in the vegetable crisper section of the refrigerator (55° to 60°F/12°15°C and 85 to 90 percent humidity). Tomatillos will suffer chilling injury if stored below 41°F (5°C).
Do not store tomatillos with apples or bananas which give off a natural gas called ethylene; ethylene will cause tomatillos to darken in storage.
Tomatillos can be frozen or canned for later use. To freeze tomatillos, remove the husk, wash the fruit, and freeze them whole in a freezer container or bag. Double bagging will prevent freezer burn.
More tips: read How to Grow Tomatillos.