Do All Fruits Contain Seeds?

If you look up the textbook definition of a “fruit,” you may be surprised by what you find out.

For all those who have ever argued that a tomato is a vegetable, I have some botanical news to share. Botanically speaking, a fruit is the mature ovary of a flowering plant, and it usually develops after pollination and fertilization, as explained by Britannica’s fruit definition.

That means those “vegetables” like cucumbers, bell peppers, tomatoes and avocados are actually fruits. I know, it feels like botany is just trying to ruin grocery store organization.

Researchers at the University of California-Santa Barbara also note that fruits are the seed-bearing structures of flowering plants, which is why finding one or many seeds inside is a pretty good clue you are dealing with a fruit.

Luckily, unless you are a botanist or a chef, you probably do not need to debate the fine details of fruit versus vegetable at the dinner table. But it is still nice to know what makes a fruit a fruit, why some fruits have lots of seeds and why others seem to have none at all.

Do All Fruits Have Seeds?

Short answer: botanically, fruits are meant to contain seeds, but the fruit you buy at the store may not always have mature, noticeable seeds.

In the simplest plant-biology version, flowers are pollinated, ovules become seeds and the ovary develops into fruit. As Sciencing explains in its overview of how fruit forms in plants, flowers contain male parts, which produce pollen, and female parts, which contain the ovary and ovules.

Once pollen reaches the female part of the flower, fertilization can happen. Then the plant begins forming fruit around the developing seeds.

NOTE: Some plants can pollinate themselves, a process called self-pollination.

In many cases, though, wind, birds, bats, bees and other insects help move pollen from one flower to another. This is cross-pollination, and it is one reason pollinators are so important to our food supply.

From the plant’s point of view, fruit is not just a tasty snack for us. It is basically a seed-delivery system.

The plant makes a protective, often delicious, outer package so its seeds have a better chance of being carried, dropped and eventually grown into a new plant.

What Are “Seedless Fruits?”

Seedless fruits are still fruits. They just do not contain mature, fully developed seeds in the way we usually expect.

As Scientific American explains in its article on how seedless fruits are made, fruit can sometimes develop without seeds through a process called parthenocarpy. In other cases, seeds may start to form and then stop developing, leaving only tiny soft traces behind.

This is where the old “seedless means GMO” idea gets a little messy. Most common seedless fruits, including seedless grapes, bananas and many seedless watermelons, are not genetically engineered in the modern GMO sense.

Seedless watermelons, for example, are typically produced by breeding plants with different chromosome numbers to make triploid plants, as described by University of Missouri Extension. In plain English: they are bred to produce fruit with little white undeveloped seeds instead of the hard black seeds you find in traditional watermelon.

The FDA’s information on genetically engineered plants is a helpful distinction here, because genetic engineering is not the same thing as traditional plant breeding. Seedless fruit can come from breeding, cuttings, grafting or other propagation methods, not necessarily from genetic engineering.

Seedless bananas are another good example. They are usually grown from cuttings or plant divisions because the tiny dark specks inside the banana are undeveloped seeds and will not grow into a new banana plant.

Convenient? Absolutely. A little strange when you think about it too long? Also yes.

Why Do Fruits Have Seeds?

Fruits have seeds because plants need a way to reproduce. The seed contains the beginning of a new plant, along with stored food and a protective coat.

The fruit around the seed does several jobs. It protects the seed while it develops, and it often attracts animals that help move the seed away from the parent plant.

In nature, fruit is less about making a perfect smoothie and more about helping the next generation of plants survive.

Think about berries being eaten by birds, apples dropping from trees or animals carrying fruit away from the plant. The seeds may end up in a new location where they have more room, sunlight and soil access to grow.

This is also why truly seedless fruits are not usually the big success story in the wild. A plant that consistently produces fruit with no viable seeds would have a hard time keeping its species going without help from growers.

Why Do Some Fruits Have Lots of Seeds and Others Have One?

The number of seeds depends on the type of flower, the number of ovules and how the fruit develops. This is why a peach has one pit, an apple has several seeds and a watermelon can look like it is trying to win a seed-counting contest.

Botanists typically group fruits in a few main ways, and this is where the grocery-store version of fruit starts to fall apart a bit.

Simple fruits.

Simple fruits develop from one flower with one ovary. They may have one seed, like a peach or avocado, or many seeds, like a tomato or grape.

Aggregate fruits.

Aggregate fruits develop from one flower that has many ovaries. Raspberries and blackberries are good examples, and each little bump is its own tiny fruit section.

Strawberries are even more confusing because the red, fleshy part is not the true fruit in the strict botanical sense. Those little “seeds” on the outside are actually tiny fruits called achenes, and each one contains a seed.

Multiple fruits.

Multiple fruits develop from a cluster of flowers that join together into one larger fruit. Pineapples, figs and breadfruit fall into this group.

So, yes, fruit classification can get weird very quickly. This is why I have deep respect for botanists, but also why I do not want one in charge of labeling the produce aisle.

What Fruits Have Multiple Seeds?

Many fruits have multiple seeds, but they do not always keep them in the same place. Some tuck their seeds neatly in the center, while others spread them throughout the flesh.

Pomes.

Apples and pears are pomes. Their seeds sit in the core, beneath the edible flesh and skin.

Berries.

Botanical berries include grapes, kiwis, bananas, tomatoes, peppers and eggplants. Cucumbers and watermelon are also berry-like fruits in the gourd family, even if no one is calling a cucumber a berry in real life.

Legumes.

Peas and beans are also fruits botanically because they develop from flowers and contain seeds. We usually call them vegetables or protein foods nutritionally, which is another reminder that botany and nutrition do not always use the same language.

Citrus fruits.

Oranges, lemons, limes and grapefruits often contain multiple seeds, although many commercial varieties are bred to be seedless or nearly seedless.

What Fruit Contains the Most Seeds?

The pomegranate is usually the fruit people think of first when it comes to lots of seeds. Each juicy little aril surrounds a seed, and one pomegranate can contain several hundred of them.

Papaya, passion fruit, figs and many seeded watermelons can also contain a lot of seeds. Bananas, on the other hand, are a fun exception because wild bananas can be packed with hard seeds, while the bananas we eat today mostly have tiny undeveloped seeds.

What Fruits Have Only One Seed?

Fruits with one hard pit are often called stone fruits or drupes. As Basic Biology explains in its overview of angiosperm fruits, a drupe has a fleshy outer part surrounding a hard inner layer that protects the seed.

Examples include peaches, plums, cherries, nectarines, apricots and olives. Avocados are also commonly treated as a single-seed fruit, even though botanists may describe them a little differently depending on the classification system being used.

Coconuts and dates are other examples that fit into the one-seed conversation. Not exactly lunchbox fruit for most people, but they count.

Fruits and Their Seeds

Of course, there is a reason some people make an entire career out of plant biology. It can get quite a bit more complex than “fruit has seeds, vegetable does not.”

Still, the big takeaway is simple: fruits develop from flowers, and they are naturally connected to seeds. Some have one seed, some have many and some store-bought seedless fruits only have tiny undeveloped seeds because growers have learned how to breed or propagate them that way.

Want to make this less of a brain-twister? Pick a few fruits from your kitchen, cut them open and count the seeds.

Try an apple, avocado, kiwi, strawberry and watermelon, then compare what you see. It is a very low-effort science experiment, and you get a snack at the end, which is my favorite kind of experiment.

If you are interested, you may also want to check out how much potassium is in strawberries.