delight. Considered to be a top – even the best – paste tomato, this tomato carries a robust, complex flavor in a plum tomato form.

Originally from southern Italy and prized for use in sauces, This variety brings heirloom characteristics of vigorous growth and exceptional flavor to the garden. Even if we don’t live in the shadow of Mount Vesuvius, with fertile soils and boundless sunshine, we can imbue a little of the Italian countryside in our own gardens and kitchens by growing ‘San Marzano’ heirloom tomatoes.
What are ‘San Marzano’ Tomatoes?
These Italian heirlooms are famous for their exceptional flavor in pastes and sauces. These plum, or paste, tomatoes feature a complex, rich flavor perfect for preserving, canning, and fresh eating.

True ‘San Marzano’ tomatoes originate in the Campania region of southern Italy, in the volcanically rich soils of Mount Vesuvius. Italian-grown ‘San Marzano’ tomatoes are said to be sweeter and less acidic than those grown in other regions.

These superior paste tomatoes are a prized export protected under an official governmental convention, the Denominazione d’Origine Protetta, or Protected Designation of Origin. This designation protects significant foods and foodways of Italian origin.

The designation means certifying jarred and canned tomatoes with an official seal. The tomatoes must be strains of the original heirlooms, grown outdoors, harvested by hand in the summer, and jarred halved or whole (you won’t find true San Marzanos as fresh produce, chopped, or diced in cans). The cans are recognizable in grocery stores and markets and are pricy because of their specialty.

Tomatoes grown outside the region are sometimes called “San Marzano-style” tomatoes. For our own taste of the Italian countryside, we can grow this specialty heirloom in our gardens.

Characteristics
This variety yields loads of long, narrow, pointed plum tomatoes, growing in clusters of six to eight tomatoes each. Fruits mature 70-90 days after transplanting. These are large for paste tomatoes, with each oblong fruit weighing about five to six ounces and growing three to four inches long. ‘San Marzanos’ are sweet in flavor and have low acidity. The bright red tomatoes have less water and seed content than other plums, making them meaty and thick – ideal for pasting.

In addition to their delicious flavor, these plants are vigorous indeterminate growers with good disease resistance. Plants resist fusarium and verticillium wilts, which are common (and often fatal) fungal issues for tomatoes.

‘San Marzano’ is an indeterminate tomato with long vines that reach six feet or longer. Plants grow all season and produce fruit from late summer through frost. As productive fruiters, they need a large tomato cage or staking/trellising for best growth and support.

Native Area

‘San Marzano’ is named for its town of cultivation, San Marzano sul Sarno, in the Salerno province of Campania south of Naples. This region of southern Italy features abundant sunshine, mild temperatures, and fertile soils.

Its ancestors are small tomatoes originating in coastal South America, with a narrow growing range bordered by the Andes Mountains from Ecuador to Chile. Humans cultivated this small-fruited plant, spreading its range throughout Central and South America. The fruits that became the modern tomato began in cultivation some 7,000 years ago.

Explorers and colonists from Spain brought domesticated tomatoes to Europe in the 15th and 16th centuries. They rose in popularity in cuisine in the 17th and 18th centuries.

Planting
Tomatoes require warm air and soil temperatures for best growth. These heirlooms are open-pollinated and grow easily from seed. Start seeds indoors four to six weeks before your final frost date for best results. Transplant seedlings outdoors one to two weeks after the last frost or as nighttime temperatures exceed 55°F (13°C).

When choosing a garden location for tomatoes, pick a spot where you haven’t grown other nightshades in the past year. Tomatoes benefit from an annual crop rotation. As a nightshade, they’re susceptible to diseases from other nightshades like eggplants, peppers, potatoes, and tomatillos. Rotating crops helps avoid lingering soil-borne diseases.

In the ground, space plants two- to three feet apart to allow for long vines and good air circulation. For row plantings, space rows three to four feet apart.

Plant tomato seedlings deeply to promote a robust root system, with two-thirds of the stem in the ground and one-third exposed. The stem has a special plant adaptation – its hairs and nodes set roots for more vigorous plants and higher water and nutrient absorption.

The sprawling vines need sturdy support to keep fruits and stems upright. A five-foot-tall by two-and-a-half-feet-wide tomato cage put in place at planting suffices. Or, opt for trellising or staking to support the fruiting vines.

To grow in containers, opt for a 10-gallon or larger pot with good drainage. Install the vine support structure at the time of planting.
How to Grow
‘San Marzano’ tomatoes are prolific growers and easy-care tomato plants. Give them plenty of sunlight, consistent water, and good air circulation for the best health and vigor.
Maintenance
Pruning isn’t necessary with caged tomatoes, but pinching off low offshoots helps direct nutrients to the upper parts of the plant, especially with staked or trellised plants. Pinch off suckers as they appear to inhibit detracting growth and increase airflow around the base of the plant.

Mulch after the sun has had time to warm plant roots for growth. Mulching too early and at planting can inhibit the sun’s warmth from reaching the surrounding soil. When stems reach 18-24 inches tall, layer two to three inches of weed-free straw around plants to help with moisture retention, weed suppression, and soil temperature regulation.