If you're growing tomatoes, you'll probably have green tomatoes left on your vines at the end of the season. Don't waste those unripe tomatoes. Try these three suggestions to use up every one of those green tomatoes.

How to use green tomatoes

Even though we look forward to the cooler weather of autumn, the change of seasons means your first frost isn't far off. 

You've been keeping a watchful eye on both the weather and your tomato plants, which are still full of green tomatoes that seem to be in no hurry to change color.

Tomato plants are frost-sensitive and love hot, sunny weather. That first frost will be the end of your tomato harvest.

Is it possible to force green tomatoes to turn red faster, or will you have to bury them in the compost pile along with all that slimy, frost-killed foliage? Is there any hope?

How to predict a frost

It's possible to predict a frost with pretty good accuracy. 

According to The Old Farmers Almanac, if you live in the northern or eastern USA and the daytime temperature is over 75°F, the nighttime temperature will probably remain above freezing; if you live in the desert southwest, the magic number is 80°F.

A cloudy nighttime sky will act as a blanket and keep your garden warmer than a clear, starry night. A light overnight breeze will keep the air warmer too, although a strong, cold wind will blow the warm air away and there will be a higher chance of frost.

Gardens situated on a slope or a hilltop are more likely to survive a cold night, since the coldest air settles in the lowest places.

Tomato plants can usually survive a light, short frost (less than four hours) if you give them a little help. Cover the plants with a blanket or sheet to keep the frost off, and remove it during the day. 

A hard frost when the low temperature reaches 25°F or lower for four hours or more will certainly spell doom for your tomato plants, whether you've covered them or not.

How to encourage tomatoes to ripen on the vine

Can you hurry the ripening process and change those tomatoes from green to red before your first frost arrives? 

Stressing your plants slightly can sometimes trick them into ripening more quickly.

Try withholding water for an extra day or two, so instead of watering every three days, wait a fourth or even a fifth day before watering. 

I know plants don't "think," but this is the only way I can describe the process: stressing the plant makes it "think" that its time is running out and it better produce seed in a hurry, so the tomatoes will often ripen sooner.

How to ripen tomatoes after picking

Hopefully that first tip will reduce the number of green tomatoes still on your plants at the end of the season, but you'll surely have some that aren't yet ripe. 

When you're out of options and must pick them or lose them, try one of these tricks:

• Pick green tomatoes with about an inch of stem attached and place them in a paper bag with a banana. Bananas give off ethylene gas, which will encourage the tomatoes to ripen. Use a cardboard box if you have more than will fit in a paper bag.

• Pick the tomatoes, leaving about an inch of the stem attached, wrap each one in a piece of newspaper and place in a single layer in a cool place (garage, unheated room, or basement).

• Pull up the entire plant with tomatoes still attached and hang it upside down in the garage or another unheated space.

Check the tomatoes weekly and remove those that have started to change color. You can place them on a warm windowsill to finish ripening.

If you leave the still-green tomatoes for another week or two, more of them will change color. Some years I've had tomatoes ripen after a month.

How to use green tomatoes

Green tomatoes should not be eaten raw. They contain solanine, which can be toxic if consumed in large amounts.

Tomatoes that are dark green contain higher levels of solanine than those that are pale green or slightly orange. Tomatoes that have begun to change color, even just slightly, will probably ripen using the methods we talked about above.

If you don't have the space to store your unripe tomatoes while they ripen, or don't want to wait, you can use them in any of these delicious ways:

Fried green tomatoes - dip sliced tomatoes in cornmeal and fry. Or dip in egg batter first, then in a cornmeal-and-flour mixture and fry.

Grilled green tomatoes - marinate your sliced tomatoes in something spicy or garlicky and grill them to perfection. Layer them on burgers, add to a salad or eat as a side dish.

Green tomato salsa - boil or roast green tomatoes to increase their flavor, chop them up and make delicious green salsa. Green tomato salsa is excellent in nachos, quesadillas, tacos and of course with tortilla chips.

You can freeze or can the salsa to preserve it, but if you plan to can your green salsa, be sure to follow an approved recipe so the final product will be safe to eat.

In other words, don't change the proportions or amounts of tomatoes, peppers and onions, or add or substitute any other ingredients other than dry spices and seasonings. If you want to change up the recipe, freeze it instead of canning.

Green tomato ketchup - I'm told it's sweet and mild and almost reminiscent of applesauce.

Green tomato hot dog relish - onions, peppers, spices, sugar and vinegar will turn your chopped green tomatoes into a delicious relish that’s quick and easy to make. If you plan to can your relish, be sure to follow an approved canning recipe such as this green tomato hot dog relish recipe.

Green tomato jam or marmalade will wake up your breakfast routine. Lemon juice and zest provide a touch of citrus that balances the sweetness of the sugar or honey. Spread your marmalade on toast for a delicious morning treat.

Green tomato taco or enchilada sauce is easy to make with just a few ingredients: tomatoes, vinegar, salt, garlic powder and onion powder. One of my favorite home-cooked meals is chicken enchiladas made with green enchilada sauce. Delicious!

Sauteed green tomatoes can be added to a salad, or serve them as a side dish with grilled or roasted meat.

Freeze green tomatoes by slicing and placing them in a single layer on parchment-paper-lined cookie sheets. Put the cookie sheets in the freezer for several hours. 

When frozen, transfer the tomato slices to freezer bags, label and date the bags and return to the freezer. Use your favorite fried green tomato recipe to enjoy this treat any time of year.

Is it worth the trouble of ripening and using green tomatoes?

Tomatoes are a very healthy food. They have a high concentration of carotenoids, including lycopene, an antioxidant that may reduce the risk of cardiovascular disease, cancer, and eye diseases. 

Unripe tomatoes, while not as good a source of nutrients as fully ripe, red tomatoes, still have health benefits. One serving is rich in antioxidants and vitamin C, contains 2 grams of protein and 2 grams of fiber, and has about 42 calories.

(But remember, don't eat raw, green tomatoes! They must be cooked.)

Besides the health benefits, if you've nurtured your tomato plants from seedlings, nursed them through the summer heat and watered them daily, it's hard to say goodbye at the end of the season. 

Ripening tomatoes indoors or using them green is certainly worth the time and effort.

With this three-pronged strategy (ripening on the vine, ripening after picking, and using them green), you don't have to let the last tomatoes of the season go to waste.

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