by Leslie Cox; September 28, 2020
Any time now you should start paying close attention to the overnight long-range forecast because you will want to harvest the rest of your tomatoes before the first hard frost happens.
A hard frost is when air temperature is held at -2 °C (28 °F) for 4 consecutive hours. This frost can cause quite a bit of damage to tender plants and vegetables but not necessarily kill the whole plant.
A killing frost is when air temperature drops to -4.5 °C (24 °F). These low temperatures will kill tender plants…depending on the plant species. Some can survive one or two killing frosts but not consecutive or sustained ones.
Check out my Garden Tip: How to store green tomatoes for the method which works well for us. Truthfully, we have enjoyed eating homegrown tomatoes as late as March but that is only if I have not turned too many of them into Green Tomato Mincemeat with brandy!