By Kathy Conner Cornell
Southside Master Gardener
Ever heard of ground cherries? It was a new plant to me also but we are going to give it a try this growing season. Ground cherries, Physalis pruinosa, used to be commonly grown before we depended on grocery stores for our produce needs. It is easy to grow if you grow your own fruits and vegetables. The problem is that it doesn’t ship well. With the reality of going to the grocery store and seeing so many empty shelves, a lot of us are making the effort to have a vegetable garden this summer.
These ground cherry seedlings are ready to go in the ground as soon as the danger of frost is past and the soil has warmed.
Ground cherries are a relative of tomatillos. As with the tomatillo, the fruit is covered in a husk. When ripe, ground cherries turn bright yellow and fall to the ground hence their name. Though several varieties are native throughout the Americas and Eastern Europe, ground cherries taste like tropical treats. Their pineapple - vanilla flavor brightens pies, jams, and chutneys. They are equally delicious eaten raw, dried, or cooked. Because they are so tasty you might want to make sure you harvest the ripe, fallen fruit on a regular basis lest nibblers like squirrels and kids beat you to it. The fruit is yellow to gold, and about the size of a small cherry tomato. An old-fashioned garden plant, ground cherry plants are shorter than 30 inches, and may sprawl rather than grow upright.
Since a good friend propagated my seedlings, I am going to leave this advice to someone with ground cherry experience, Bill McCaleb. Start ground cherries indoors as you would tomatoes, about six to eight weeks before the normal last frost date. Plant seeds one-fourth inch deep in flats containing sterile, soilless germination mix. Use a heating mat to keep the flat at 75°F to 85°F until seedlings emerge. Be patient as this seed can take from two to four weeks to germinate. After emergence, a soil temperature of 70°F is ideal. Warm soil is better than cool. Monitor potting mix moisture, as heating mats will dry the mix faster. Provide bright overhead light for the seedlings. Using a grow light, keep the light 2 – 3 inches above the emerging plants so they don’t get leggy as they grow. Thin or transplant seedlings after true leaves appear so that seedlings are two inches apart. Grow plants under bright light.
A week or so before you plan to set the plants out in the garden, reduce watering.
Harden the plants off by placing plants outside where they will receive a couple of hours of sunlight and wind protection. Experience has shown that using the shade of an understory type tree or shrub will provide protection as the plants harden off. Expose plants to more and more sunlight over the next week or two.
Transplant to the garden after all danger of frost has passed and the soil has warmed. Because of the bushy growth, allow ground cherry plants at least 24 inches of space in all directions, or you can plant one plant per container, when using this method. Improve your soil by adding well-rotted manure or compost in spring or fall. Ground cherry plants may not need more fertilizer. Ground cherries need about the same amount of nitrogen as any other crop. Too much nitrogen fertilization will lead to plants that are too bushy, leafy, and slow to bear fruit.
As with tomatoes, ground cherries are susceptible to some of the same insects such as the cutworms, cucumber beetle, flea beetles and later on the season, tomato hornworm. Because ground cherries are nightshade plants, like tomatoes and potatoes, they contain solanine and other solanidine alkaloids. Leaves, stems and un-ripened fruit should be avoided.
Tomatillos and ground cherries are vulnerable to many of the diseases that affect potatoes, tomatoes, peppers, and eggplant. These diseases can overwinter in the soil and affect the next year’s crop, just like tomatoes. To avoid issues, you should employ best management practices such as crop rotation. Use good cultural control practices to reduce disease problems to a tolerable level and allow for a successful harvest. Starting with a sterile grow mix will at least provide the best media to get these plants off to a good start. Maintain good drainage so roots do not stay wet, but maintain the dampness needed for healthy growth. This will help avoid ‘Early Blight’, ‘Anthracnose’, ‘Late Blight’, and ‘Tobacco mosaic virus’. That said, avoid planting ground cherries where last years tomatoes grew.
When fully ripe, ground cherry husks will be dry, and the fruit will drop from the plant. A mulch of clean, weed-free (wheat, barley, or oat) straw will keep the fruits clean if they drop. Ground cherries self-seed in the garden, so don’t be surprised to see some young plants sprouting forth in the fall. It is a good idea to clean up any fallen fruit even if you do not intend to eat it, so that you will not have to deal with all the volunteer plants next year.
If left in the husk, ground cherries will keep for a week or two. Because their fruits are truly ripe when picked, they have a shorter shelf life than tomatillos. You can keep ground cherry fruit as jam or preserves. You may also can or freeze them like berries.
If an easy to grow fruit that is delicious hasn’t convinced you to try them, maybe some nutritional information will. In one cup the ground cherry offers 74 calories, 1 gram of fat, 3 grams of protein, and 16 grams of carbohydrates (4 grams of which is dietary fiber). The ground cherry is an excellent source of Vitamins A, C, and B-3 (Niacin). They are also a good source of Vitamins B-1 (Thiamin) and Vitamin B-2 (Riboflavin) and the minerals non-heme iron, calcium, and phosphorus. A good publication for additional information is Growing tomatillos and ground cherries in home gardens by University of Minnesota Extension. Give these tasty treats a try this season.
While we are all still practicing ‘social distancing’ due to COVID-19, and all county buildings are closed to the public, if you have questions on ground cherries or other vegetables, you can best reach an Extension Master Gardener or Extension staff member by sending an email to email@example.com or you can use firstname.lastname@example.org. Stay safe and eat healthier by growing some of your own vegetables for best flavor and freshness.