One question that people will call me with is how to tell if a fruit or vegetable is ripe or not. Different plants ripen differently. Some will continue to ripen after they’ve been picked, others need to ripen attached to the plant. Let’s talk about what causes plants to ripen and how to tell if some common fruits and vegetables are ripe or not.
Fruits and vegetables are divided into climacteric and non-climacteric. The difference between these groups is their response to the hormone ethylene. Ethylene is a hormone that plants produce to induce ripening. Climacteric fruits and veggies will continue to ripen after they have been picked. Non-climacteric fruits and veggies won’t continue to ripen. Instead, they will soften and rot as they age. Some crops are sensitive to ethylene and so shouldn’t be stored with climacteric crops that produce ethylene.
Apples, pears, peaches, plums, potatoes, and tomatoes are some examples of climacteric plants. Blueberries, blackberries, raspberries, cherries, cucumbers, eggplant, grapes, strawberries, peppers, squash, and watermelon are all examples of non-climacteric crops. Some examples of plants that are sensitive to ethylene and so shouldn’t be stored with climacteric crops are asparagus, broccoli, cucumbers, green beans, kale, onions, peas, peppers, squash, and watermelon.
Now that we know a little more about the ripening process let’s talk about how to tell when the best time to pick some of the most commonly grown crops around here are.
Tomatoes are an easy one to tell when they are ripe because they start to turn red. You can pick tomatoes before they are fully ripe on the vine. Because they are climacteric, they will continue to ripen. I’ve put tomatoes up in the kitchen windowsill so that they’ll ripen. Sometimes it is advantageous to pick something before it’s fully ripe so that you make sure critters don’t get it before you.
Apples and pears can be a little more challenging to tell when they are ripe. Different varieties will ripen at different times. In addition, the entire tree may not ripen at the same time. If the apple or pear stem breaks away easily from the tree then it’s ripe. Turn the fruit sideways to see if it pops off. Depending on the variety, you can use color to tell if the fruit is ripe. If you cut an apple open and the seeds are dark brown, it’s ripe.
Blueberries will be plump with a deep blue color. They also have a white powder on the skin that keeps them fresh longer.
Squash and zucchini should be harvested when they’re 4-8 inches long. They’ll both grow longer if left on the vine, and you can still eat them if they’re big, but they get tougher as they age. You should be able to push your fingernail into the skin.
Sweet corn is ripe when you can puncture a kernel with your fingernail and milky fluid comes out. As soon as corn is picked, it starts to lose flavor. Refrigerate it to retain flavor.
Pick peas when the pods have plumped out. If they start to wrinkle, they’re getting overripe. You can always open a pod to see if the seeds are swollen, but still tender. Beans are ready when you can see the seeds bulging through the sides of the pod.
Pick peppers when they are shiny green. If you let them sit on the bush longer and they start to change to orange or red and they’re getting hotter. If that’s what you’re looking for, let them sit.
If you have questions about when plants are ripe contact your County Extension Office or email me at Jacob.Williams@uga.edu.