Few things in life are as annoying as waiting for that first green tomato of the season to ripen or your green tomatoes turn red before frost kills plants. Ripening is a complex procedure in tomatoes, making it difficult to predict exactly how much time it is going to have a fully-formed green tomato to turn red.
Inside the Machine
Tomato ripening is a complex process involving tens of thousands of chemical reactions. Pigments like carotene and lycopene are created as chlorophyll breaks down, causing the gradual coloration of this fruit. At exactly the exact same time, acid levels are rising, causing starches in the fruit to convert into sugars and softening the tomato. Under perfect circumstances, this may all occur in as little as a week, however, often requires 20 days or longer in certain weather conditions.
Factors Affecting Ripening
Many factors play key roles in ripening tomatoes, such as ambient temperature, soil temperature, the plant’s natural ability to produce the hormone ethylene and even the number of fruits demanding ripening. Ambient temperatures over 85 degrees Fahrenheit or soil temperatures over 80 degrees would be the primary reasons why tomato plants set the brakes on ripening. Occasionally, a plant is so heavily laden with green fruits that it simply lacks the energy to encourage them all to ripening. Some gardeners remove the smallest tomatoes in an over-burdened plant; raising water and sulfur for plants experiencing hot roots may also accelerate ripening.
Tomato fruits are sometimes ripened inside by craftsmen when sunscald or pest insects are a persistent problem or whenever frost starts to threaten. A tomato picked in the “breaker” point, when a blush of its finished color looks, will ripen fully on the kitchen countertop if kept out of direct sunlight. Tomatoes harvested at the breaker stage contain all of the sugars of a completely vine-ripened tomato and will develop exactly the same taste.
Hastening the Final Harvest
As winter looms and frost threatens, many gardeners rush into the lawn to cover their plants, trusting those remaining fruits will ripen until the plants die. You can speed ripening in your tomatoes by eliminating any green fruits that are not fully developed — these tomatoes will probably not grow further due to cooling temperatures anyhow. Withholding water and fertilizer also will help accelerate the ripening procedure. If a killing freeze is predicted, uprooting your tomatoes and hanging them upside down in a basement or garage will make it possible for the rest of the fruits to ripen on the vine.