The first frost of fall calls the end of your homegrown tomato season; yet often the tomato plants are loaded with fruits. Fortunately, you can harvest and ripen the green tomatoes with this simple method and enjoy tomatoes for several more weeks.
When the first frost is predicted, harvest the developed fruits. Discard any blighted or cracked tomatoes and forgo the smaller undeveloped fruits.
Gently arrange in a box or bin, no more than two deep.
Place an apple in the bin. Apples emit ethylene gas, which will hasten the tomato ripening process. Commercial tomato growers use ethylene gas to ripen grocery store tomatoes.
Cover loosely with newspaper or a grocery bag. This will help keep the ethylene gas in the bin. Do not use plastic as this will encourage mold.
Place the bin out of the sunlight in a space with normal room temperature. Tomatoes stored in a cool basement, root cellar, or porch will ripen slower than a warmer room.
Check daily and remove any tomatoes that begin to shrivel or show rot. Not every tomato can be saved. Transfer ripened tomatoes to your kitchen and complete the ripening on your counter.
Monitor the weather news to determine when the first frost is expected in your area. If the weather predicts a light frost at 32 or 31 degrees with warmer weather following, you can place a blanket over the plants and harvest another day. If there is a continued cold spell, it is best to call the season done. Tomatoes cannot survive frost and will not continue to ripen when it is 35 degrees outside.
Not all young fruits will successfully ripen. Discard or use in a green tomato recipe.