The arrival of the first hard frost often leaves a substantial harvest of green tomatoes clinging to the vine. Frost damage quickly leads to decay and an unappetizing texture, threatening to waste a season’s effort. However, this predicament does not mean the end of the tomato season. By understanding the science of the tomato’s ripening process and employing simple strategies, gardeners can successfully save this bounty. This guide provides methods to identify, harvest, ripen, and utilize the end-of-season crop.
Identifying and Harvesting End-of-Season Fruit
The most pressing concern is to harvest all viable fruit before the first hard frost arrives. Exposure to freezing temperatures ruins the tomatoes’ internal structure and prevents subsequent ripening, causing the fruit to quickly turn soft and mushy. When harvesting, leave a small piece of the stem, often called the calyx, attached to the tomato. This small cap helps seal the fruit and reduces the risk of rot during storage.
Successful indoor ripening depends on distinguishing between immature and “mature green” tomatoes. Mature green fruit has reached its full size and shows a slight color change from dark, waxy green to a lighter green, often with a hint of yellow or pink blush near the blossom end. An internal check confirms maturity if the gel surrounding the seeds has begun to form, unlike the solid interior of immature fruit. Tomatoes that are too small and hard will likely never ripen and should be set aside for culinary use. After picking, immediately sort the tomatoes, removing any showing blemishes, cracks, or disease, as one damaged fruit can quickly spoil the entire batch.
Techniques for Indoor Ripening
Ripening is driven by ethylene gas, a natural plant hormone that triggers color change, softening, and flavor development. This gas is the key to successfully ripening tomatoes indoors. Contrary to popular belief, sunlight is not required for this process; a cool, dark environment is often preferable for slow, steady ripening.
The paper bag or cardboard box technique is effective because it concentrates the naturally released ethylene gas around the fruit. Place a single layer of mature green tomatoes in a paper bag or a newspaper-lined box, ensuring the fruit are not touching to prevent decay. For faster results, introduce a high-ethylene-producing fruit, such as a ripe banana or apple, into the container. This external source accelerates the ripening process, often causing the tomatoes to turn red within three to seven days.
For a larger harvest, a cooler storage area, such as a basement or garage kept between 55°F and 65°F, is ideal for long-term, staggered ripening. These cooler temperatures slow the process considerably, allowing fruit to ripen gradually over several weeks or months. Another technique involves harvesting entire vines and hanging them upside down in a cool, dark location. This allows the fruit to draw remaining nutrients from the vine, potentially resulting in a more flavorful tomato, though it requires substantial vertical space. Regular monitoring is essential for any indoor method, as any fruit that begins to mold or rot must be removed immediately to protect the rest of the harvest.
Culinary Uses for Unripened Tomatoes
Green tomatoes that are too immature to ripen offer a unique flavor profile and wide array of culinary applications. The distinct tartness and firm texture of the unripened fruit lend themselves well to preparations that rely on a strong structure and acidic flavor. This makes them a popular ingredient for classic savory dishes and long-term preservation methods.
The most recognized use is the classic preparation of fried green tomatoes, where slices are coated in a cornmeal batter and fried until crisp. The heat softens the flesh and mellows the acidity, creating a tangy and savory side dish. The fruit’s enduring firmness also makes green tomatoes excellent candidates for pickling in a vinegar brine with spices. This method capitalizes on their tartness, resulting in a crunchy, long-lasting condiment.
Green tomatoes are also a foundational ingredient in relishes, chutneys, and sweet preserves like jam or mincemeat. When cooked down with sugar and spices, the fruit’s pectin helps the mixture set into a thick preserve, and the inherent acidity provides a necessary flavor counterpoint to the sweetness. Unripened tomatoes contain glycoalkaloids, primarily tomatine, a mild toxin that decreases significantly as the fruit ripens. While mature green tomatoes are generally safe for consumption, especially when cooked, very small, hard, and bitter fruit should be avoided.