Michigan State University Extension
Preserving Food Safely - 01600202
Store tomatoes that have not been injured by frost; fruits from vigorous vines will store better than fruits from exhausted vines. To avoid chill injury, harvest tomatoes exposed to temperatures of less than 50 degrees Fahrenheit in less than five days.
Remove stems to prevent puncturing other tomatoes. Wash and dry fruit. Wiping dirty fruit when it is dry may scar skin and shorten storage life.
Sort tomatoes into like stages of maturity or use these three classifications: those showing red, mature green, and green. Mature green tomatoes have reached mature size and are light green to whitish.
Pack tomatoes of like stage 1 or 2 layers deep in boxes or trays. Mature greens will reach an eating stage in 14 days when stored between 65 and 70 degrees Fahrenheit. Ripening can be slowed by lowering the temperature to 50 degrees Fahrenheit.
Never expose tomatoes to temperatures below 50 degrees Fahrenheit for more than a few days. At 55 degrees Fahrenheit, mature green tomatoes will need 25 to 28 days to ripen. An airy cellar or outbuilding with moderate humidity is ideal for storage. Too much humidity will cause decay and too little will cause shriveling.
Fruits can be wrapped individually to overcome humidity that is too low. Wrapping will not be effective if the humidity is very low. If tomatoes are stored in perforated plastic bags, decay may increase.
Sort tomatoes at 7 to 10 day intervals to separate the red and green tomatoes and to dispose of any rotted fruit.