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The Dilemma of Determining Fruit Maturity and Ripeness

GARDEN TIPS – written by Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA Written September 27, 2015

Gardeners are often faced with the dilemma of knowing when to harvest their fruits and vegetables. When is the right time to pick them and will they ripen afterwards? At the risk of revealing that I am a botany nerd, technically fruit are the protective female organs of flowering plants that contain their “babies” or seeds. The protective fruit may be fleshy structures like apples or dry structures like nuts. Apples, peaches, grapes, tomatoes, peppers, and melons are all examples of fleshy fruit.
Physiologically, fruit are mature when their seeds are fully developed. However, if you have ever encountered a humongous fully mature zucchini you will know that the desirable stage for harvesting and eating this “fruit” is when they are much smaller with tender skin and undeveloped seeds. As consumers, there are some vegetable fruits that we prefer to eat when they are immature, like summer squash, and others when fully mature, like melons. When it comes to tree fruit like apples or peaches, we usually find the fruit much tastier when fully mature and ripe.
Ripening is also a physiological process. It involves changes in the fruit, such as the flesh becoming softer and sweeter and the skin changing from one color (often green) to another. A variety of chemical changes can occur during ripening, including the breakdown of starches into sugars leading to a sweeter flavor. Softening results from a change of insoluble pectin in the cell walls to soluble pectin. The acid content of the flesh also decreases as the fruit ripen.
Now back to the original question of when to pick fruit and if they will ripen off the plant. The answer is some do and some do not. Because of this, horticulturists divide fruit into two groups. The group that do not ripen after picking tend to produce only small quantities of ethylene gas as they ripen. Ethylene is an odorless naturally occurring hydrocarbon gas. It is sometimes referred to as a plant aging hormone. Fruit that do not ripen after picking include cherries, grapes, raspberries, strawberries, other berries, watermelon, and citrus fruits. These are picked when fully mature and ripe.
The second group are fruit that produce greater amounts of ethylene as they ripen and do ripen after picking. These include apples, pears, peaches, nectarines, apricots, plums, cantaloupes, bananas, and tomatoes. These fruit should be harvested at the “right” stage of ripeness after becoming fully mature. I am sometimes asked how to determine when to pick homegrown apples. It is tricky as the timing is based on the color of the skin, how easy it is to detach from the tree, flavor, and softness.
Commercial fruit growers have equipment for testing skin color, amounts of sugar, and flesh firmness. Gardeners should periodically check for sweetness by tasting the fruit. The flesh will be starchy if it is not ripe. Gardeners can also use their noses to check the fruits’ aroma and their eyes to judge skin color. Apples change in firmness from rock hard to slightly softer flesh that gives just a bit with a press of the thumb. Ripe apples should separate from the tree fairly easily with a slight upward twist. A gardener must sacrifice a few fruit to determine the “right” time, but it is better than harvesting an entire crop of unripe or over-ripe fruit.
Now that fall is here, I suspect frost is not far off, so next week we will tackle picking winter squash and green tomatoes.


written by
Marianne C. Ophardt
WSU Extension Faculty
for the Tri-City Herald, Kennewick, WA

The National Garden Bureau has named 2005, the ‘Year of the Melon.’ Every year the National Garden Bureau recognizes a different vegetable with this designation. This year melons, the cousin of the watermelons, squash, cucumbers, and gourds, get their special recognition.

What exactly is a melon? According to the dictionary it’s ‘a large round fruit of various plants of the gourd family, with sweet pulpy flesh and many seeds.’ Botanically the group of plants we generally call ‘melon’ (with the exception of watermelon) is named Cucumis melo. These melons are divided into two groups. The Reticulatus group contains the melons that most of us know as muskmelon or cantaloupe. They’re easily recognized by their netted skin. When ripe, their aromatic fruit easily detaches or ‘slips’ from the vine. In recent years, gardeners have started to discover Charentais and Galia melons, two different melons in this group. More about them later….

The other group of melons is the Inodorous group. They’re commonly referred to as smooth or winter melons. Their fruit are not aromatic when ripe and they don’t slip off the vine. This group includes the popular honeydew melon, as well as casaba, crenshaw, Christmas, and canary melons.

While many of our vegetable crops can be traced back to their native origins in the wild, melons have never been found growing in the wild, except for garden escapees. Melons are believed to have their origins in the hot climates of southwest Asia, in the area of Iran and India. They’ve been a cultivated crop for over 4,000 years and have been grown in American gardens since the 1600


As a vegetable crop, melons love hot, dry conditions and thrive at temperatures between 70 and 80 degrees. They’re best planted after the soil warms up in the spring and after the threat of frost is past. Many gardeners, especially those in cooler climates, try to get a jump on the season by starting their melon seed indoors and planting the transplants outdoors at the right time. However, this should be done only about 15 to 18 days before planting outdoors. If planted too early, the plants become too big and suffer much more transplant shock when placed in the garden.

In cool climates, gardeners also try to get a head start by warming up the soil in late winter or early spring. This is done by placing black plastic mulch out in the garden where melons (and other warm season crops) will be planted. The black plastic absorbs heat and warms the soil. Once the soil reaches a temperature of 60 degrees or more, seeds or transplants can be planted by making x-shaped slits in the plastic… as long as the danger of frost is past and the weather has warmed.

Whether you plant seeds in the soil or use transplants, be sure to give your melon vines plenty of room to grow. If you plant in ‘hills,’ be sure to thin your plants when they have two sets of true leaves, leaving the two strongest plants per hill. If you plant through a black plastic mulch, situate plants four feet apart on six foot centers.

Once your melon vines are up and growing in the garden, they need plenty of water. It’s best to keep the soil evenly moist. To conserve water, consider using drip irrigation. You will want to cut back on watering a bit just before the melons are expected to ripen. Gardeners and growers have found that too much water from rain or irrigation three weeks before harvest can adversely affect the fruit’s sweetness and flavor. You don’t want to drought stress the plants, but they should not have an over abundance of water during those three weeks.

Now let’s talk about the different kinds of melons that you might find in a seed catalog or perhaps a grocery store or farmer’s market. First the netted or summer melons…

Ananas Melons (also known as Middle Eastern melons): The fruit have an oval shape with a medium fine netting over a pale green to orange rind. The flesh is usually white, very sweet, and aromatic.

Athena Cantaloupes (cantaloupes found in the eastern U.S.): The fruit have an oval shape, coarse netting over a yellow-orange rind, and slight suturing. (Suturing is the longitudinal indentations down the sides of the fruit.) The flesh is firm, thick, and yellow-orange.

Charentais Melons (also known as French Charentais): The fruit are small, with smooth gray to gray-blue rinds and sutures. The flesh is orange.

Galia Melons (Israeli melons): The fruit have pale netted rinds. The sweet flesh is pale green to white and described as spicy-sweet or banana-like in aroma.

Muskmelons: These are the American cantaloupes with which we are most familiar and commonly found in the grocery store. They have orange flesh and netted skin.

Persian Melons: The fruit is bigger than cantaloupes, with a dark green rind and light brown netting. As the fruit ripens the rind turns light green. The flesh is bright pink-orange with a delicate flavor.

Now for some of the smooth skinned winter melons…

Canary Melons: The fruit is oblong shaped with a bright yellow rind. The flesh is juicy, mild and cream colored.

Casaba Melons: The fruit is oval shaped with a pointy end and a wrinkled yellow skin. The flesh is almost white and very sweet.

Crenshaw Melons: A cross with a Casaba, the fruit have a more oblong shape and a rind that ripens from green to yellow. The peachy-orange colored flesh has a strong, spicy aroma.

Honeydew Melons: This popular melon has smooth, white to greenish-white rinds. The flesh is sweet and usually green, but can also be white or orange.

Oriental Melons: The fruit are small with a very thin, yellow rind with white sutures. The flesh is pale peach to white and sweet. The seeds are very small. Because the seeds are so small and the rind is very thin, the entire melon can be eaten.

So celebrate the ‘Year of the Melon’ by growing some melons in your garden this year… or at least trying some that you may not have grown or tasted before.

Published: 2/19/2005 1:59 PM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

It’s that time of year again… time when owners of cherry, apple, crab apple, and pear trees need to be spraying their trees with pesticides to prevent wormy insects from destroying the fruit. This is especially important because area gardeners are neighbors to the commercial fruit industry. Unchecked pests in backyard trees, even single trees, are sources of infestation for nearby orchards. This causes problems for the commercial fruit grower and can lead to the greater use of pesticides to control pests or even a failure to keep the fruit pest-free and marketable.

Owners of backyard fruit trees and certain fruit-bearing ornamental trees should be “good neighbors” and make the effort to adequately control cherry fruit flies in cherries and codling moth in apples, crab apples, and pears. This is no easy task. It involves regularly spraying the entire crown of the trees with several pesticide applications or more during the growing season. It also requires the proper equipment for spraying and the application of the recommended chemicals at the right times. Quite simply, it’s a lot of work.

It is a lot of work and unsuspecting gardeners who planted fruit trees may find this task of pest control a burdensome task for which they don’t have the time… or the inclination. Unfortunately, they don’t have a choice. They are required by county law to control these tree fruit pests. So what options do you have if you have a fruit tree with wormy fruit, but don’t want to keep spraying it on a weekly basis?

Option One: The simplest solution is to remove the offending trees. Gardeners often have difficulty parting with a tree or any other plant from their yard or garden, but they should think of this as “tough love” for a tree that has become a delinquent.

Option Two: Gardeners who dream of picking fresh fruit from their own backyard trees, may want to consider planting fruit trees that don’t usually require regular spraying to control wormy pests in the fruit. This includes apricots, peaches, and plums. Plums are the most dependable and lowest maintenance tree fruit crop for would-be backyard orchardists. My favorite plums are ‘Autumn Sweet’ a newer large purple plum that bloom late, has firm sweet flesh, and dries well; ‘Shiro’ a round, yellow Japanese plum with sweet, juicy flesh; and ‘Elephant Heart’ a reddish-purple heart-shaped Japanese plum with tasty, sweet red flesh.

Option Three: It doesn’t seem to make much sense for gardeners to grow apples in our region where we can easily buy fresh fruit at packing houses, u-pick farms, or farmers’ markets. The supply of apples may be abundant and relatively inexpensive, but you can’t always find “your” favorite variety. I doubt I’ll ever find ‘Empire’ (my favorite) apples locally. You can grow your favorite “back-home” apple variety without sprays for codling moth using paper bags to protect the fruit.

At the same time you thin the fruit, you cover each one left on the tree with a special paper bag. That’s how they grow apples in Japan! A “Fruit Protection Bag” is a waxed paper bag with a double twist-tie that allows you to secure them over the developing apple. Raintree Nursery in Morton, Washington sells Fruit Protection Bags for apples and pears in groups of 100. Contact Raintree Nursery at 360-496-6400 or

What ever option you choose, be a good neighbor and keep the worms out of your backyard tree fruit. If you have fruit trees and need to know what sprays can be used to control codling moth in apples and pear and cherry fruit fly in cherries, contact the WSU Extension Office of Benton County at 735-3551 for a Home Orchard Pest Management Chart.

Published: 5/7/2007 4:09 PM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Some might wonder why the U.S. government spends over a billion dollars on agricultural research every year. The USDA Agricultural Research Service (ARS) employs 2,100 scientists and supports 100 research locations, including the WSU Irrigated Agricultural Research and Extension Center in Prosser.

The ARS mission is to “conduct research to develop and transfer solutions to agricultural problems of high national priority and provide information access in order to ensure high-quality, safe food, and other agricultural products, assess the nutritional needs of Americans, to sustain a competitive agricultural economy, enhance the natural resource base and the environment, and to provide economic opportunities for rural citizens, communities, and society as a whole.” Wow! A billion dollars seems like a lot of money, but if they can accomplish all this it’s worth it… in my opinion.

Grapes seems to be a crop of particular interest for ARS around the country. In our region Prosser researcher Julie Tarara, along with colleagues Paul E. Blom and John C. Ferguson, is field-testing an automated system for estimating grape yields. They measure the changes in tension of the trellis wire supporting the vines. As the vines grow and the grapes ripen, the tension on the wire increases. Knowing when and how much the tension is increasing can help growers estimate yields and adjust their cultural practices (watering, pruning, and harvesting) to maximize yield.

In the San Joaquin Valley of California a long-standing grape breeding program, dating back to 1923, has yielded varieties which have become some of our favorite grapes at the supermarket. This includes Flame Seedless, a popular red seedless grape; Crimson Seedless; Autumn Royal, a black seedless grape; and Princess, a white seedless grape.

Not resting on their laurels of the past and present, the current team of breeders in the program have introduced two new red seedless grapes that they have judged to be “top-notch.” Horticulturist David Ramming describes Sweet Scarlet as a specialty grape that’s “truly exceptional” with crunchy flesh, a thin bright raspberry red skin, and a hint of muscat flavor. Ramming also praises Scarlet Royal, the other new variety they’ve introduced. Its berries are “sweet, firm and meaty” with a nice dark-red color.

There are also ARS researchers around the country working with grapes. In Orgeon, they’re working on a way to assay or measure the amount of anthocyanins (those natural healthful compounds found in fruits and vegetables) in grapes and other crops. In Idaho, they’re studying more environmentally sound ways to grow grapes in a stressful desert climate. In New York, California, and Colorado they have established genebanks to preserve more than 3,000 different grapes, including wild, rare, and domesticated ones. These genebanks protect the rich and diverse gene pool of grapes from around the world.

In Mississippi, ARS is also supporting grape research. Mississippi! If you are a wine connoisseur, you may know that they don’t grow premium wine or table grapes in the southeastern U.S. However, they do grow muscadine grapes, also called “scuppernongs.” These small, three-fourths-inch diameter berries are quite flavorful. They’re used to make juice, jam, jelly, sauce, and even dessert wine. A native grape, muscadines thrive in the warm and humid southeastern climate and are resistant to a variety of pest problems that plague European wine grapes and table grapes. Research is aimed at changing muscadine production practices and breeding to produce larger, seedless berries with thinner skin, firmer flesh, higher amounts of sugar, and increased levels of anthocyanin and other phenols.

Muscadines are already a healthy choice when it comes to phenols. Scientists, James B. Magee and Betty J. Ector found that two ounces of unfiltered muscadine juice (or one serving of jam or one muscadine muffin) have the same amount of resveratrol as four ounces of red wine. While red wine is well known for its antioxidant punch, resveratrol (a heart-healthy phenol) is not found in high concentrations in other grapes, including wine grapes.

Thanks to the efforts of ARS scientists and others, grapes have become a very successful crop in Washington and elsewhere in the country. This is reflected in the growing wine industry, as well as in the production of quality table grapes, raisins, grape juice, and other grape products. However, ARS has also contributed to the success of the ornamental horticulture industry… but I’ll tell you about that another time.

Published: 1/6/2007 10:47 AM


written by

Marianne C. Ophardt

WSU Extension Faculty

for the Tri-City Herald, Kennewick, WA

Why do gardeners go to all the trouble of growing their own fruit trees? I think the answer is flavor. There are many varieties of fruit that are not available in grocery stores or even farmers’ markets. A backyard orchard is the only way to get specialty varieties, including favorite heirloom varieties.

With a backyard orchard, gardeners can also control when the fruit is picked. This can mean all the difference in getting the best flavor. Before we proceed, we should discuss the difference between mature fruit and ripe fruit. Ripe fruit are ones that have developed their full flavor and sweetness and have the right amount of softness. Mature fruit are physiologically mature, but not necessarily ripe and ready to eat.

Some types of tree fruit ripen best on the tree, others can be picked at the mature stage and will ripen off the tree. Commercially harvested fruit is often harvested when fully mature, but when still firm to make shipping and packing easier. Home gardeners have the luxury of picking fruit when fully mature and ripe, allowing fruit to develop full color, flavor, and sweetness. Of course fully ripe fruit tend to bruise much more easily and don’t store as long.

So what types of fruit will ripen off the tree if picked at the fully mature stage? Apricots, peaches, and nectarines will ripen of the tree. There is a definite color change from green immature fruit to a yellow ground color. All three are usually mature when the fruit can be easily separated from the tree with a slight twist. For the very fullest flavor, they do best if left on the tree to ripen.

Plums will also ripen off the tree, but the best flavor comes when they’re ripened on the tree and allowed to develop sweet and soft flesh. If you’re wanting to pick plums when mature and still firm, wait for the skin color to change from green to the appropriate color for the type (red, purple, or yellow) and there should be a slight softening of the flesh at the tip end.

Cherries don’t ripen much off the tree and should be picked only when their full flavor and sweetness have fully developed, but while still firm.

Apples are harvested at the right firmness and sweetness for the variety. Commercial growers use special equipment to determine sugar content and the hardness of the flesh, but home gardeners can figure this out more subjectively by simply tasting the fruit. If you pucker up or the flesh has an astringent flavor, they’re not ready yet. Apples should be harvested when fully mature and sweet, but still firm. This is especially important if you plan to store them for a while. One clue to maturity is how easily the fruit comes off the tree. Lift or roll and twist the fruit stem away from the spur. If mature, it should separate fairly easily with the stem remaining attached to the fruit.

Pears are tricky. They’re best harvested when mature but before they’re ripe. If allowed to ripen on the tree, they’ll have gritty flesh and the cores will have a tendency to break down and become mushy when stored. There are two types of European pears. Winter pears, such as Bosc, Comice, and Anjou, ripen late in the season and require a period of cold storage after picking. Fall pears, such as Bartlett, Clapp Favorite, and Orcas, ripen earlier and don’t need the cold storage time before they can be used.

Both fall and winter pears have the same indicators for maturity. They will still be green, just starting to turn a yellow-green. The stems will separate easily from the spur when the fruit is lifted and twisted. Check the seeds inside, they should be brown. Also, the flesh will yield a “smidge” to pressure instead of feeling rock hard. (I told you it was tricky!) Winter pears are stored for about three to four weeks under cool conditions (40 to 33 degrees) before they’re allowed to ripen at room temperature.

Asian pears are quite different. They should be allowed to ripen on the tree, just like apples. Their skin color will start to turn from green to yellowish. Asian pears have the best flavor when eaten fresh and not stored for any length of time.

Published: 9/30/2006 11:05 AM


written by Marianne C. Ophardt WSU Extension Faculty for the Tri-City Herald, Kennewick, WA In late May or early June when fruit are about one-half inch to one inch in diameter, it’s not unusual for home gardeners to become alarmed about lots of fruit falling off their backyard orchard trees. Even though alarming, it’s not unusual for this shedding of fruit to occur. The phenomenon is called ‘June drop.’ Why would a healthy fruit tree drop so much of its fruit? It’s because the tree has set more fruit than it can support with water and nutrients. It’s hard to believe, but fruit scientists say that if you have good full bloom on an apple tree, only about one bloom out of twenty is needed to produce a good crop. When too many of the blossoms set fruit, the tree sheds the fruit it can’t support. The smaller fruit and the fruit that may not have received complete pollination are the first ones to fall. June drop is the natural way a tree thins its crop load to allow the strongest and biggest fruit to mature. Even with June drop, many fruit trees still need additional hand thinning by gardeners who want to insure good fruit size and tastier fruit. The more fruit left on a tree, the smaller they will be at maturity. Heavy crop loads of maturing fruit can also lead to limb breakage. Also, allowing an overload of fruit one year can significantly reduce the crop the following year. If you find your fruit tree has successfully set a good crop of fruit, you should consider hand thinning to achieve a crop of good-sized, good-tasting fruit. Thinning by hand should be done early in the season before the fruit reach one-inch in diameter. Thinning later will reduce the effectiveness of the process on fruit size and quality. How many fruit should you leave on a tree? That depends on the type of fruit. Over the years, horticulturists have determined the recommended spacing of fruit on fruit tree branches for each type of fruit. Apples – 6-8 inches between fruit, leaving only one fruit per cluster, keeping the largest fruit when possible Pears – 6-8 inches between fruit, leaving only one fruit per cluster, keeping the largest fruit when possible Peaches, nectarines, and large plums – 3-5 inches between fruit Apricots & plums – 2-4 inches between fruit on the branch Cherries – seldom need thinning Fruit drop from poor pollination also occurs earlier in the season, soon after the petals fall from the blooms. It’s less noticeable than June drop because the fruit are so small. The cause of this drop is a lack of pollination or poor fertilization. (Fertilization is when the sperm from the pollen reaches the ovules in the seeds.) Some types of fruit trees are ‘self-unfruitful’ and need pollen from another variety to set fruit. Self-unfruitful trees include most varieties of apple, pears, sweet cherry, and Japanese and American plums. Other types of fruit trees are ‘self-fruitful’ and do not need cross pollination to produce fruit, but their fruit set may sometimes be enhanced by bee activity and some cross pollination. These include most varieties of sour cherries, apricots, peaches, and European plums. Lack of bee activity due to a low bee population, bad weather, or competition from nearby flowers are common causes of early fruit drop. Weather extremes, especially frost, can also interfere with pollination and fertilization. If lots of fruit are dropping from your trees right now, don’t worry. It’s just ‘June drop.’ You may still need to take off additional fruit to insure quality fruit.

Published: 6/3/2006 11:15 AM



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