The Scarlet Tomato
Before a tomato turns red, it must first reach full size or what is called "a mature green stage".
Once it reaches "a mature green stage" the outside temperature needs to range between 50F and 85F. Any cooler or warmer and the production of Lycopene and carotene are halted, preventing the tomatoes from turning green to red.
As the tomato matures, it produces an odorless, tasteless gas called ethylene. Ethylene permeates the air, interacting with the fruit and stimulates ripening.
With ideal growing conditions, the mature tomatoes turn from dark green to light green to red, yellow, orange etc.
From seed to tomatoe, this process takes about 45 to 100 days!