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Do Cucumbers Turn Into Marrows

Marrow is a fruit in the gourd family commonly referred to as Cucurbits. This family includes melons and squashes, like watermelon, cantaloupe, cucumbers, and zucchini. Many of these have a similar appearance and can be easily confused with each other. For example, if you’re growing cucumbers, you might wonder what happens if you leave them on the vine for too long, which leads us to the question: Do cucumbers turn into marrows? 

The short answer is no; cucumbers do not turn into marrows. A marrow is a mature fruit type of a specific species in the Cucurbitaceae family, in a different genus than cucumbers. 

No matter how long the fruit is left on the vine or any other conditions, a cucumber will not turn into a marrow. This is like fearing that your apples will turn into pears; they are both in the same family but will never be able to switch between being one kind of fruit to another. 

Read on to learn more about the differences between squash cultivars and squash species and a bit of clarification on common gourd terminology. 

What is the difference between marrow and a cucumber? 

Marrow is a mature fruit of the “pepo” fruit type. A pepo is characterized by its thick outer rind and (usually) large shape and is technically a sub-classification of a berry. Think of fruits like watermelons and pumpkins, and these are good examples of the pepo fruit type.

Cucurbita pepo contains many commonly encountered cultivars such as pumpkins, crookneck squash, acorn squash, and a subspecies of summer squashes, commonly called “zucchini,” which means “little gourd” in Italian. The only difference between these cultivars is that each one is selected for a specific trait, much like wild cabbage being the main species of common cultivars such as broccoli, kale, and cauliflower. 

A marrow is simply a mature fruit in the broader C. pepo species cultivar. Marrows can be distinguished from other similar squashes because of their thick skin, and they are often larger than their summer squash counterparts, which appear to be very similar in shape and color.

A cucumber, still in the Cucurbitaceae family, is a separate genus from the marrow mentioned above or C. pepo. This genus contains melon species such as honeydew and cantaloupe

Ultimately the difference boils down to marrows and cucumbers being distantly related but distinctly different. Like how a domestic house cat is related to a tiger through many stages of evolution, your house cat will not turn into a tiger, no matter how much you feed it. Biologically, the differences between the two are large enough to be distinct and separate entities. 

Is a courgette the same as a cucumber?

Cucumbers and courgettes are not the same. Courgette is a French word in origin that has become the British term interchangeable for what we commonly know as “zucchini” and is about Cucurbita pepo varieties. Cucumbers, which are in the same family of gourds, are Cucumis sativus and do not have cultivars that vary so widely within the same species. 

Courgette, zucchini, and marrow refer to the same cultivar of C. pepo but at different growth stages. Courgettes are small and harvested early to preserve flavor. Zucchini is usually a bit larger and more mature, with marrows being the most mature stage. From courgette to the marrow, they look like they can be entirely different plants: one is picked when it is young, flavorful, and thin-skinned, whereas a mature fruit on the same plant is thick-skinned and not nearly as flavorful because of its higher water content. 

Preparations are also different, with cucumbers mostly used in cold preparations such as salads or pickling, but zucchini or “courgette” are typically cooked or grilled. Zucchini can still be consumed raw like cucumber and vice versa, though key textural differences make each one better suited to their respective, typical preparations. 

How can you tell the difference between marrow and courgette? 

When harvested for the best flavor and texture, courgettes are thinner skinned “summer squashes” and are usually small, between 3-5 inches. “Courgette” is a term that can refer to immature marrows, though the term “marrow” can apply to more than one subspecies in the C. pepo species. 

Marrows are typically larger, about 8 inches long, with a thicker rind. This is because they are more mature than the courgette. Upon fully ripening, the skin becomes harder, making them easier and safer to store until they are ready to be processed. They can be stored more similarly to winter squashes and can stay good several weeks after harvest. Texturally, a marrow is more similar to an eggplant (or aubergine) and should be treated before cooking, such as salt to draw out excess moisture. This is due to its long time on the vine, causing an increased need for water. Therefore the final fruit retains more of the water used in the growing process.

Final thoughts

There is a fair amount of confusion surrounding all of the terms used to describe the Cucurbita pepo cultivar members, and understandably so. Marrows are similar to what we know as simply “squash,” with the appearance of zucchini but the hardiness and thick skins of related winter squash like pumpkins or spaghetti squashes. 

Ultimately, it comes down to being familiar with some terminology and understanding the differences between specific species and cultivars within a separate species. 

The most important thing to recall is that marrows are just as cucumbers are cucumbers; there is no genetic switching between cultivars due to leaving the fruit on the vine for a longer period after it would typically be harvested. Marrows are a specific stage of a specific species that is not the cucumber plant and cannot spontaneously take over the patch of cucumbers growing in your garden.