Blushing tomatoes may ripen indoors.

Tomatoes are very sensitive to cold temperatures. Blankets or tarps can protect the vines from a light frost and perhaps give you another week or two of gardening.

When a hard frost (28°F or colder) is expected, you need to run out to the garden and rescue whatever tomato fruits you can. Here is how to ripen the tomatoes indoors:

Any tomato showing a blush may ripen off the vine. Start by cleaning the fruits. Discard fruits with spots or cracks -- they will likely rot before they ripen.

Set tomatoes on a sheet of newspaper, and then place another newspaper sheet over the fruits. This traps ethylene, a natural gas that fruits emit when ripening. Some gardeners wrap each tomato to trap the ethylene. Other gardeners place apples nearby the tomatoes since apples emit lots of ethylene.

Keep tomatoes out of direct sunlight. Do not set them on a windowsill. If placed in a sunny area, the outer skin will redden before the inner flesh develops flavor.

Room temperatures are best. Cooler temperatures prevent the tomatoes from developing their full flavors. Warmer temperatures create the same problem, plus increase the chances of rotting.

Check your tomatoes every day or so. Remove any that are rotting.

If all goes right, you can enjoy the goodness of homegrown tomatoes later this fall.

Written by Tom Kalb, Extension Horticulturist, North Dakota State University. Photo courtesy of Andrea R.