What Is a Vegetable Marrow?

A marrow, also called a vegetable marrow, is simply a variety of Cucurbita pepo, a plant that yields numerous types of squashes and pumpkins. Through selective breeding, gardeners have turned Cucurbita pepo into the acorn squash, ornamental gourd, pumpkin, zucchini, vegetable marrow and more. These are known as different varieties, and they’re abbreviated “var.” A marrow is Cucurbita pepo var. fastigata. 

Explaining Marrows, Squashes, Cucumbers and More

The fastest, easiest way to explain the difference between these similar vegetables is to list their scientific names. Then, we’ll break down what it all means.

• Cucumber: Cucumis sativus 
• Squash: Any plant in the genus Cucurbita
• Pumpkin: Any squash that looks like a pumpkin 
• Marrow: Cucurbita pepo var. fastigata
• Baby marrow (South Africa): Cucurbita pepo var. cylindrica
• Courgette (Britain, Iran, Ireland, France, the Netherlands, Singapore, Malaysia and New Zealand): Cucurbita pepo var. cylindrica
• Zucchini (North America, Japan, Australia, the Czech Republic, Italy, Germany and Austria): Cucurbita pepo var. cylindrica

Although they look similar, cucumbers are not a type of squash, because they’re not in the Cucurbita genus. Instead, they’re in the Cucumis genus. They taste and smell very different than squash on the inside.

Marrows are very large, fibrous vegetables. They may be solid green or have white stripes running down the length of the body. They’re the fastigata variety of Cucurbita pepo. 

Baby marrows, courgettes and zucchinis are all the same vegetable. They simply have a different name based on which country you’re in. They’re the cylindrica variety of Cucurbita pepo. 

“Pumpkin” is actually a vernacular term for any type of squash that looks or tastes like a pumpkin. They may not even belong to the same species. For example, Cucurbita maxima, Cucurbita moschata, Cucurbita argyrosperma, Cucurbita ficifolia and Cucurbita pepo are all different plant species that yield “pumpkins.” Scientists think Native Americans first grew pumpkins around 9,000 years ago, although no one is certain. 

Selective Breeding

To complicate matters, some people call immature marrows “courgettes,” even though they’re a different variety of plant. They only call them “marrows” when they reach full size. In other regions, people only call striped squashes “marrows.” 

Although it would be wrong to call a regional dialect incorrect, these terms don’t fit the standard definition of vegetable marrows belonging to C. pepo var. fastigata and courgettes belonging to C. pepo var. cylindrica. It’s the equivalent of calling broccoli “cauliflower” because it looks similar and technically belongs to the same species. 

In fact, broccoli, cauliflower, kale, cabbage and brussels sprouts are just different cultivars of the same plant — Brassica oleracea. Like the Cucurbita pepo plant that produces pumpkins, zucchinis and marrows, humans have selectively bred Brassica oleracea so much over time that it produces different versions of the same vegetable. We did the same thing with Canis lupus to produce chihuahuas, Great Danes and Xoloitzcuintles, all of which look so different they could be mistaken for distinct species. 

Growing Marrows

Now that you know what a vegetable marrow is, why not try your hand at growing one?

Buying Seeds

Depending on where you live, it may be easy or challenging to find marrow seeds. Vegetable marrows are common in the United Kingdom, for example, but rare in the United States. This is somewhat ironic considering that Cucurbita is native to South and Central America. Regardless of where you live, you can most likely order vegetable marrow seeds online.

Sowing

Marrows like full sun and moisture-retaining soil. You can sow them inside or start them directly in the ground outdoors in early summer. If you’re starting them outside, plant the seeds on their side about an inch deep in moist soil. Place two or three seeds in each hole. If more than one germinates, only keep the strongest one. Sow your marrows around three feet apart. Cover the planting site with netting or cloth for two weeks. 

It’s preferable to start your seeds indoors so they’re protected from pests. Inside, you can plant them around half an inch deep in moist soil. It must be 65 to 75 degrees Fahrenheit for them to germinate. Next, place the pots in a greenhouse or sunny windowsill inside a clear polyethylene bag. Once the seedlings begin to sprout, remove the plastic bag.

Planting

If you started your marrows inside, eventually they’ll need to go out. In early summer, start placing their pots outdoors in the daytime and bringing them in at night. Do this for a week to help the plants acclimatize. The next week, leave them outside all day and night in their pots. 

When that’s done, you can finally plant them in a sunny spot in the yard. Mix in compost or fertilizer for best results. Space plants at least three feet apart. Consider companion-planting your seedlings with another species, like a bean plant, to maximize your use of space. 

Watering

Vegetable marrows need consistently moist soil. In the heat of summer, you may even need to water them every day. Avoid wetting the leaves in the process. 

Fertilizing

Once the plants start to bear fruit, you can give them high-potassium fertilizer every 10 to 14 days. 

Mulching

Add mulch over the soil around your marrow plants to help the planting site retain moisture. Leave a space around the base of the stem so the stem doesn’t rot.

Upkeep

Remove any damaged or diseased leaves. Pick off any squash bugs, caterpillars or slugs feeding on the plants. 

Harvesting

You can either pick the marrows when they’re young — which is when they’re tender and have the most flavor — or go for gold at a giant marrow contest, in which farmers and gardeners grow the biggest vegetables possible. The world’s largest marrow weighed just over 256 pounds and was more than five feet long!

What Is a Vegetable Marrow?

Now you know the answer to the question, “What is a vegetable marrow?” A marrow is a fastigata variety of the Cucurbita pepo plant, which also grows pumpkins and zucchinis. People selectively bred the plant to produce a wide variety of vegetables. 

Marrows are large, fibrous and somewhat tough, but they’re delicious in cakes, soups and stir-fries. Pick one up at your local grocery store or grow your own to harvest it at the peak of flavor.