We all suffer from late ripening tomatoes. Tomatoes need warmth to ‘kick off’ the ripening process. Warm weather encourages the tomatoes to produce ethylene which ripens the fruit. As October approaches and cold weather is looming we can look at the abundance of unripe green tomatoes on the vines and resign ourselves to making chutney etc. I find mine do eventually go red but by November they are no longer very sweet.
One method I use to help hasten the ripening process is to place banana skins on my tomato plant pots, in the greenhouse. Bananas give off ethylene in large quantities and this extra gas will help. I also continue to feed the plants at least once a week. As frost is forecast you can put green tomatoes indoors, inside brown paper bags with a banana skin or pull up the vines and hang them upside down in the garage for a slower ripening.
Simple but effective!