For tiny green tomatoes developing on plants now, gardeners might wonder if this fruit will mature before frost.

Fruit development depends on tomato variety, day and nighttime temperatures, and amount of sunlight received between now and frost. And we don’t know when the first frost will be.

Below is the typical period of time a tomato needs from fruit set to maturity. Following that is an average range of days from flowering to maturity for other vegetables.

For tomatoes, according to Ward Upham at Kansas State University, the first 2 to 3 weeks after new fruit forms, growth is slow with slicing tomatoes reaching about the size of a golf ball.   

More rapid growth then occurs over the next 3 to 6 weeks resulting in a tomato that is a mature size but still green. It then takes several more days for the tomato to ripen and develop red color.  

From flower pollination to a mature green tomato takes 5 to 9 weeks with 40 to 50 days being typical. Tomatoes that reach the mature green stage can be harvested to then ripen indoors, if frost is in the forecast.

Outdoors, the optimum temperature for ripening mature green tomatoes is 68 to 77 degrees Fahrenheit.  Red color does not form when temperatures are above 86 degrees F, but yellow pigment continues to develop. This is why tomatoes that ripen during very hot weather may be yellowish-orange.

Tomatoes picked at the green, mature stage will ripen indoors with little loss in quality.  Mature tomatoes are full-sized and have a greenish white skin color. If frost threatens, harvest mature green fruit that are solid, firm, and free of defects.

Ripe red tomatoes can be stored for one to two weeks if held at 50 to 55 degrees F and for a shorter time if temperatures are warmer. The kitchen counter is a good place to store ripe tomatoes. Do not store tomatoes in a refrigerator as cold temperatures result in a loss of flavor. Monitor for fruit flies.

To ripen mature, green tomatoes, place the fruit in single layers on newspaper or in a box. Each fruit could be be individually wrapped in newspaper. Ideally, store tomatoes in a cool, dark location such as a basement.

Check tomatoes often during storage. Discard any soft or decaying fruit. When tomatoes begin to develop color, remove the newspaper and place them at room temperature to finish ripening.

For other vegetables, here is an average range of days needed from pollination to maturity. Again, this is affected by weather and vegetable variety. And while green peppers and cucumbers are harvested and eaten when immature, the rest of these need to mature on the vine to be of eating quality.

Green peppers require about 45 to 55 days; slicing cucumbers 15 to 18 days; muskmelon 42 to 46 days; icebox watermelon 28 to 32 days; large watermelon 50 to 60 days; pumpkins 60 to 90 days; acorn and butternut squash about 60 days; and Hubbard squash 80 to 90 days.  

On melons, squash and pumpkins, if small fruits developing on vines are unlikely to reach maturity before the first frost, it might help to pinch the small ones off so the plants energy goes into maturing larger fruit.

If fruit flies are an issue, place small jar of apple-cider vinegar nearby. Put a drop of dish soap in it to break surface tension and place plastic wrap over the opening. Punch a few holes in the wrap with a pencil. This will attract and trap fruit flies. Avoid storing fresh produce on counters for too long.

By: Kelly Feehan, Extension Educator