San Marzano tomato

Looking for the perfect heirloom sauce tomato? Look no further than San Marzano!

The San Marzano Tomato is an Italian heirloom plum-type tomato cultivar prized for its refined, balanced flavor. This thin, pointed variety is most often used in cooked applications such as on pizzas or in pasta sauce. San Marzano tomatoes grow best in warm climates with long, Mediterranean-type summers, but only tomatoes grown in Valle del Sarno in Italy can be sold as true DOP “Pomodoro San Marzano dell’Agro Sarnese-Nocerino”.

Read on to learn all about San Marzano tomatoes.

San marzano tomatoes

The San Marzano tomato

The San Marzano Tomato is the classic Italian paste tomato. This tomato variety is an heirloom from San Marzano sul Sarno – a town in the Campania region of southern Italy, near the city of Naples. The sweet, elongated, pointy plum-type tomatoes make delicious cooked tomato sauces. San Marzano tomatoes are also canned as whole tomatoes for export around the world.

San Marzano tomatoes have firm pulp and low water content. The thick skin protects the pulp from predators and harsh environmental conditions. The density and low amount of water in these tomatoes help them store well into autumn. The shape of the fruit is longer and thinner than many other paste tomatoes. A San Marzano tomato has only 2 seed cavities (locules), while many other plum tomatoes have 5 seed cavities.

San Marzano tomato plants are indeterminate, growing on long vigorous vines. The vines continue to grow longer and longer throughout the growing season, continuing to produce clusters of delicious San Marzano tomatoes. These tomato plants are drought-tolerant, salt-tolerant, and disease-resistant.

San marzano tomatoes - ripe showing inside

What do San Marzano tomatoes taste like?

San Marzano tomatoes have an intense tomato aroma and a flavor that perfectly balances a rich sweetness with refreshing acidity. This sweet-tart balance is most pronounced when the tomatoes are cooked. San Marzano tomatoes can be used to make truly top-notch tomato sauce.

San marzano tomato plants

How to grow San Marzano tomatoes

To grow San Marzano tomatoes, start with either a seedling plant from the nursery or grow your own baby plants from seed. If growing from seed, purchase your tomato seeds in the winter and plant them indoors 6-8 weeks before the last frost in your area (usually this means sowing seeds indoors sometime in February-March).

Whether you’re growing from seed or from purchased seedlings, don’t put them outdoors until the threat of frost has passed. Tomato plants, including the Mediterranean San Marzano, can be damaged at temperatures below 43°F (6°C).

San marzano tomato seedling

Once outdoors, plant your San Marzano tomato plants in nutrient-rich soil that drains water easily. These are large plants that should be spaced about 2 feet apart. They grow particularly well in raised garden beds and need a vertical stake or heavy-duty tomato cage/tower.

Tomatoes need a minimum of 6-8 hours of direct sunlight per day. The plants need all this sunlight to create energy to create those yummy tomatoes! You’ll also need to keep the plants well-watered to keep them from becoming stressed and even from becoming nutrient-deficient.

Pomodoro san marzano dell'agro sarnese-nocerino

Are San Marzano tomatoes hard to grow?

San Marzano tomatoes are not hard to grow, but they do grow more easily with a bit of preparation.

The first tip is to purchase a potted baby tomato plant instead of starting your San Marzano tomatoes from seeds. Tomato seedlings can be finicky and require supplemental lighting and occasional repotting. San Marzano is a very popular variety, with seedling plants often widely available at plant nurseries.

Secondly, get your tomato planting area ready prior to planting. Plant the seedling San Marzano plants in a raised garden bed if possible. Use a nutrient-rich organic potting mix that allows water to drain out easily. Add a substantial trellis for the tomato plant’s vines (skip the small standard tomato cages). San Marzano tomato plants also benefit from consistent water from a drip irrigation system.

Tomato growing on san marzano tomato plant

How long do San Marzano tomatoes hard to grow?

San Marzano tomatoes typically mature 75-85 days after the seedling plant is transplanted outdoors. Expect to care for the plant outdoors for almost 3 months before tomatoes start to ripen. Once the harvest starts, however, tomatoes continue to grow and ripen until the autumn frost arrives.

How tall do San Marzano tomato plants get?

San Marzano tomato plants are long, vining, indeterminate types that can easily grow over 6′ tall if staked vertically. Be sure to add a strong support stake (and potentially an outer trellis ring) to help the plant support its delicious crop!

Real san marzano - pomodoro san marzano dell'agro sarnese-nocerino

Harvesting San Marzano tomatoes

Harvest San Marzano tomatoes at peak ripeness if they are to be enjoyed immediately, either fresh or in a cooked sauce or crushed on a pizza. Ripe San Marzano tomatoes tend to be rather firm, due to the variety’s naturally low water content. A soft tomato may indicate over-ripeness (and a sweet, slightly-off flavor). While ripe San Marzanos are generally bright red, they can sometimes have a pale color when ripe due to sunscald:

“An important thing to remember is that the temperature tomatoes experience when ripening can significantly affect the color. Fruits that are exposed to midsummer sun may develop the pale and withered coloring indicative of sunscald. A red tomato that ripens at temperatures above 85°F (29°C) will not develop a rich, deep pigment and will appear a washed-out pink or even yellow.”

Epic Tomatoes: How to Select and Grow the Best Varieties of All Time, by Craig LeHoullier

San Marzano tomatoes can also be harvested when under-ripe, particularly if a frost is in the forecast. Leave them at room temperature in a protected area rather than putting them in the fridge (cool temperatures can encourage mealy texture).

Seed packet - san marzano tomatoes

Are San Marzano Tomatoes heirloom tomatoes?

San Marzano tomatoes are heirloom tomatoes that have been produced in the Campania region of Italy for centuries. For a virtual visit to the San Marzano tomato fields in Italy, check out Stanley Tucci’s Searching for Italy episode on the Naples/Campania area.

San Marzano is perhaps the most famous heirloom plum-type tomato and is revered for their excellent flavor in sauces and cooked dishes. Many modern introductions were bred from San Marzano, including the popular Roma tomato variety available in grocery stores around the world.

San Marzano: This indeterminate variety is a type of plum tomato and has a somewhat longer season than typical sauce tomatoes. They were popularized near San Marzano, Italy, and are a popular commercial variety. They have a somewhat pointy shape and a strong, somewhat bittersweet taste.”

The Complete Guide to Growing Tomatoes: Everything You Need to Know Explained Simply — Including Heirloom Tomatoes, by Cherie Everhart
Neapolitan pizza in naples

What’s so special about San Marzano tomatoes?

San Marzano tomatoes are a specialty due to their perfectly balanced sweet-tart taste and their long history in Italian cuisine. San Marzano tomatoes, along with Pomodorino del Piennolo del Vesuvio, have been designated as the only tomatoes that can be used for Vera Pizza Napoletana (True Neapolitan Pizza). Many modern varieties (including the Roma) were bred from San Marzano heirloom tomatoes.

What’s the difference between Roma and San Marzano tomatoes?

The Roma tomato is a modern variety bred from the San Marzano heirloom tomato. Roma tomatoes are directly descended from the San Marzano. The Roma tomato was introduced to farmers in 1955 by the USDA’s Agricultural Research Service, whereas the San Marzano has been grown on the Italian coast for centuries.

San Marzano tomatoes are generally thinner and less uniform than Roma tomatoes. The tip of San Marzano tomatoes is also much more pointed than Roma fruits. San Marzano tomatoes tend to have an intense, balanced sweet-tart taste, while Roma tomatoes have a more mild flavor that tends towards acidic.

Are San Marzano tomatoes from Italy?

The San Marzano tomato has been grown along the Italian coast in the Campania region for centuries, making it a true heirloom tomato from Italy. Italy remains a major producer of San Marzano tomatoes, but this variety is also now grown in countries around the world.

While the San Marzano variety can be grown in most climates worldwide, only tomatoes grown in Valle del Sarno in Italy (and in compliance with Italian law) can be sold as “Pomodoro San Marzano dell’Agro Sarnese-Nocerino”. These authentic San Marzano tomatoes are canned whole and labeled to include the EU Protected Designation of Origin logo (DOP logo).

Margherita pizza in naples italy

How can you tell real San Marzano tomatoes?

Real San Marzano tomatoes grown in the Valle del Sarno in Italy can often be distinguished from other canned tomatoes by three factors:

  • Real San Marzano tomatoes from Campania are generally labeled as “Pomodoro San Marzano dell’Agro Sarnese-Nocerino”. The Agro Sarnese Nocerino is the area near the Sarno river where the San Marzano variety originated.
  • Authentic San Marzano tomatoes are allowed to include the Protected Designation of Origin logo on the label (DOP – Denominazione d’Origine Protteta). Example brands include the Gustarosso brand of San Marzano tomatoes.
  • Real San Marzano tomatoes include the seal of the local consortium (Consorzio), as well as a unique identifying number on the can.
  • True San Marzano tomatoes from the DOP area are sold canned only as whole tomatoes or as fillets. Only imitation versions are sold as crushed or diced tomatoes.
  • The price is likely high. The Agro Sarnese Nocerino DOP region is very small and there are a very limited number of tomato growers.

While these signs can indicate real, authentic San Marzano tomatoes from the Agro Sarnese Nocerino, beware that there are many improperly-labeled imposter tomatoes. There are also many delicious tomatoes of the San Marzano cultivar that have been grown in other regions and are properly labeled as such.

Can you grow San Marzano tomatoes in the US?

The San Marzano tomato cultivar can be grown successfully in all but the harshest climates of the USA. While American-grown San Marzano variety tomatoes won’t ripen in the Mediterranean conditions of their ancestors, they can still be grown in the USA. American-grown San Marzano-cultivar tomatoes cannot be sold under the protected DOP labeling, and must state clearly that they are a “product of the USA”.

Some chefs prefer to use California-grown San Marzano variety tomatoes in their cooking, simply because they are locally produced and can also have excellent (if slightly different) flavor. That said, it is also common for chefs to search out authentic DOP-labelled San Marzano tomatoes imported from Agro Sarnese Nocerino in Italy.

Mary Jane Duford
Mary Jane Duford

Mary Jane Duford is a quintessential Canadian gardener. An engineer by trade, she tends to an ever-expanding collection of plants. In her world, laughter blooms as freely as her flowers, and every plant is raised with a dash of Canadian grit.

Mary Jane is a certified Master Gardener and also holds a Permaculture Design Certificate. She's also a proud mom of three, teaching her little sprouts the crucial difference between a garden friend and foe.

When she's not playing in the dirt, Mary Jane revels in her love for Taylor Swift, Gilmore Girls, ice hockey, and the surprisingly soothing sounds of bluegrass covers of classic hip-hop songs. She invites you to join her garden party, a place where you can share in the joy of growing and where every day is a new opportunity to find the perfect spot for yet another plant.

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