Yes, you can successfully pick green tomatoes and ripen them indoors, a common practice when the growing season ends or frost threatens the garden. Tomatoes are climacteric fruits, meaning they continue their ripening process even after being separated from the vine. Indoor ripening provides the correct environment to encourage the fruit’s natural hormonal processes. By understanding the specific requirements, you can enjoy garden-fresh flavor well into the autumn months.
Selecting the Best Green Tomatoes for Indoor Ripening
The success of your indoor harvest depends entirely on the maturity of the fruit before it is picked. Only tomatoes that have reached the “mature green” stage will ripen properly off the vine. Mature green tomatoes are full-sized for their variety and transition from a deep, matte green to a pale green color. Some may even show a faint white or light green star-shape at the blossom end.
Immature, dark green, or small fruits lack the necessary internal development and will likely shrivel or rot instead of turning red. Before storage, carefully inspect each tomato and reject any that show signs of damage, such as cracks, bruises, or soft spots, as these will spoil quickly. Gently wipe the tomatoes clean but avoid washing them, since excess moisture encourages mold growth.
Essential Indoor Ripening Techniques
Ripening off the vine is possible because tomatoes produce a natural plant hormone called ethylene gas. Ethylene is an odorless, colorless compound that triggers the conversion of starches to sugars and green chlorophyll pigments to red lycopene pigments. Indoor methods focus on concentrating this gas around the fruit to accelerate the process. Sunlight is not required for this chemical change and can cause the tomatoes to “cook” or develop tough skins.
One highly effective approach is the Box or Container Method, which works well for large quantities of fruit. Place the tomatoes in a shallow cardboard box, arranging them in a single layer to prevent them from touching. Separating the tomatoes prevents rapid spoilage from spreading. Covering the tomatoes with newspaper helps trap the ethylene gas and absorbs moisture.
For smaller batches, the Paper Bag Method is simple and efficient, utilizing a paper bag to contain the gas. To speed up the process, include an ethylene-boosting fruit, such as a ripe banana or apple, inside the bag or box. These fruits increase the gas concentration, encouraging the tomatoes to ripen faster.
For optimal results, the ripening area should be kept relatively cool, ideally between 55°F and 70°F. The environment should also maintain high humidity (85% to 95%) to prevent the fruit from shriveling, but airflow is needed to prevent mold. A cool basement, garage, or dark closet often provides the ideal conditions.
Managing Ripening Speed and Quality
You can control how quickly your tomatoes ripen by adjusting the storage temperature. Warmer temperatures, closer to 70°F, cause ripening in approximately one to two weeks. Storing the tomatoes at the lower end of the optimal range, around 55°F, can slow ripening down to about a month, extending your fresh supply. Regularly check the fruit every few days, and immediately remove any fully ripened or decaying tomatoes to protect the rest of the batch.
It is important to manage expectations regarding the final taste of indoor-ripened tomatoes. These fruits will not possess the same depth of flavor as those that fully ripened on the vine, as sugar development is limited after picking. However, the taste will still be superior to that of commercially shipped winter tomatoes. Once a tomato has fully turned color, move it to a slightly cooler location for short-term storage. Storing the fully ripened fruit at 55°F will extend its usability for a couple of weeks.