All fruits and many vegetables are in one of two categories based on their ripening characteristics:  climacteric or non-climacteric.  

Climacteric fruits and vegetables will continue to ripen after they are picked from the plant; non-climacteric fruit and vegetables stop ripening the moment they are picked from the plant.  

But which are which and why?

Ripening is controlled by several things.  One of these is ethylene.  All plants produce ethylene.  

In addition to ripening, ethylene tells dormant plants when to start growing, stimulates the repair process on wounded plants and starts the processes that ultimately lead to the death of a plant.  Due to this last characteristic, ethylene is often called the “death hormone.”  

Different fruits, vegetables and even flowers emit different amounts of ethylene as they ripen, and they all have different levels of sensitivity to ethylene exposure.  

Climacteric fruits/vegetables (the ones that continue to ripen) produce large amounts of ethylene and are very sensitive to ethylene exposure while non-climacteric are not.  

We can use this knowledge to hasten the ripening of certain fruits and vegetables by exposing them to ethylene or we can slow down the process by chilling.  

People have known how to use ethylene gas for a long time even though they didn’t know what it was.  

The ancient Chinese placed unripe pears in storage rooms and burned incense to speed up ripening the pears.  Early Egyptians started small fires in fig orchards to hasten ripening.  

The effects of ethylene on plants were first noticed scientifically in 1864 but it was not until 1935 that scientists realized that plants produced ethylene and that it is the plant hormone most responsible for fruit ripening.  

So how can knowing about climacteric and non-climacteric fruits and vegetables and the production of ethylene help you with harvesting what you grow in your garden or purchasing and storing what you buy at the farmer’s market or grocery store?  

Pick all of your fall tomatoes before the first freeze and use your knowledge of ethylene to ripen your green tomatoes.  

Put the tomatoes in a paper bag with a ripe banana or apple, close the bag and seal with a clothes pin or bag clip.  

The ethylene gas emitted by the banana/apple will help to hasten the ripening of the tomatoes. Check the bag periodically for the ripe tomatoes.  They won’t all ripen at the same time so check frequently.

Ethylene gas production by plants in your refrigerator is responsible for premature spoilage of your fruits and vegetables.  

Learning to separate the ethylene sensitive foods from the ethylene producing foods can save you a lot of money.  

The leafy vegetables like lettuce, spinach and cabbage have a high sensitivity to ethylene gas.  

Tomatoes, broccoli, cauliflower, and cucumbers are also ethylene sensitive.  Because of this none of these vegetables should be stored near apples as apples are very high ethylene gas producers.  

Your vegetables should be stored in the crisper far away from apples.

Now that you know the basics of how ethylene gas affects ripening of fruit and vegetables, you can use the table below to determine which fruits and vegetables you can pick or purchase “green” and which ones will never ripen once they leave the plant.  

It will also help you to store your produce to prevent premature spoilage.

Ellis County Master Gardeners have a website at www.ecmga.com. Check this website for information on gardening in Ellis County, sign up for a monthly newsletter or access other websites including Texas A&M Horticulture website. Questions for Master Gardeners will be answered with a return telephone call or email if you leave a message at 972-825-5175.