How To Ripen Green Tomatoes
The best way to ripen tomatoes is to allow the fruit to ripen naturally on the vines. However as frost approaches it is important to get the tomatoes into a protected area before they are ruined by the frost. This can be done in a couple of different ways:
Temperatures play an important part in the ripening process, the cooler the location, the longer it will take for the tomatoes to ripen. Likewise the warmer the room temperature the quicker they will ripen. So, it is a good practice to keep a few of the ones closest to ripening in a warmer spot, holding some back at cooler temperatures for later ripening. If you time it right, it is possible for you to be enjoying ripe tomatoes for several weeks. Avoid placing the tomatoes on a windowsill, as they are apt to sunscald. (Actually tomatoes need a dark location to ripen.)
Tomatoes that are whitish, yellowish or are in the early stages of pink to red, are the ones that will ripen the quickest. The bright green ones are the slowest to ripen and sometimes will not ripen at all.
If you have too many green tomatoes, you may want to check your recipe books for ways in which to use green tomatoes.