Easy Ways to Ripen Tomatoes Before Frost

By Scout Nelson

Many gardeners look for ways to ripen tomatoes before the growing season ends. As cooler weather approaches, green tomatoes often remain on the vine. With the right care and a little luck, gardeners can increase the chances of harvesting more ripe and flavorful tomatoes.

Tom Kalb, NDSU Extension Horticulturist, shared practical tips to help gardeners encourage tomato ripening both on and off the vine. His recommendations focus on maintaining healthy plants, managing growth, and protecting crops from early frost.

Temperature is one of the most important factors in tomato ripening. Tomatoes ripen best when temperatures stay between 68 and 77 °F. When nighttime temperatures fall into the 50s, the ripening process slows significantly.

Gardeners can help protect plants by covering them during cool nights. Blankets placed over tomato plants help hold warmth and may improve fruit ripening. This simple step can make a noticeable difference during the final weeks of the growing season.

Removing flower clusters is another useful practice. New flowers need many weeks to develop into mature tomatoes. Late in the season, these flowers are unlikely to produce ripe fruit before frost arrives.

When flowers are removed, the plant directs more energy toward the tomatoes that are already growing. This helps existing fruits mature instead of supporting new growth that may never fully develop.

Regular harvesting is also important. Overripe tomatoes left on the vine continue to use plant resources. Picking ripe fruits promptly allows the plant to focus on the remaining tomatoes.

Fertilizer should generally be avoided late in the season. Additional fertilizer does not speed ripening. Nitrogen, in particular, encourages leaf growth rather than fruit ripening. This can delay the development of mature tomatoes.

Gardeners should remove damaged or diseased leaves, especially those found on lower branches. This helps improve plant health and air movement around the vine.

Removing suckers can also be beneficial. Suckers grow between the main stem and leaf branches. They use energy that could otherwise support fruit growth. Reducing excess suckers allows more sunlight and airflow to reach the plant.

Tall tomato plants may benefit from light pruning near the top. Removing the growing tip can help redirect energy from new shoots and flowers toward the developing fruit. However, this practice is generally more useful for larger plants and has only a modest effect compared with maintaining proper temperatures.

Leaves located around the fruit should remain on the plant. These leaves help provide energy to the tomatoes and support good flavor development. Excessive leaf removal near the fruit is not recommended.

Gardeners may also remove very small fruits late in the season. While this may not speed ripening directly, it allows the plant to focus its resources on fewer tomatoes. As a result, the remaining fruits often grow larger and develop better quality.

Some gardening traditions suggest stressing tomato plants to encourage ripening. Methods such as twisting roots or striking plants are sometimes promoted. However, these practices are unnecessary and may harm the plant. Healthy growing conditions remain the best approach.

Weather forecasts become especially important as autumn approaches. Tomato plants are highly sensitive to frost. Even a light frost can damage vines and reduce production.

When temperatures approach 32 °F, gardeners can provide temporary protection by covering plants overnight. Cloth blankets and burlap generally offer better insulation than plastic materials and can provide a few degrees of protection.

If a hard freeze near 28 °F is expected, gardeners should harvest remaining tomatoes before serious damage occurs. Waiting too long may result in losses as fruits and vines freeze.

For indoor ripening, tomatoes should be placed in a single layer inside a shallow box. Covering them lightly with paper helps trap natural ethylene gas, which supports the ripening process. Room temperature conditions and good airflow help achieve the best results.

Direct sunlight is not necessary for indoor ripening. Instead, a warm and well-ventilated location helps fruits develop color and flavor more effectively.

Photo Credit: gettyimages-valentinrussanov