San Marzano Roma (Determinate Seed Line) Tomato

San Marzano Roma (Determinate Seed Line) tomato seeds grow into determinate plants reaching 49–60 in, bearing red fruit elongated plum fruit, commonly 3–4 inches. This paste tomato is especially suited to sauce, roasting, drying, canning, and concentrated tomato cooking. Maturity is 70-79 Days from transplanting.

About San Marzano Roma (Determinate Seed Line)

San Marzano Roma (Determinate Seed Line) is a paste tomato grown as Solanum lycopersicum L. Plants have a determinate habit and reach 49–60 in; support is listed as trellis. The principal mature or market color is Red, with fruit described as elongated plum fruit, commonly 3–4 inches. Reproductive classification: Open-Pollinated (OP). Maturity: 70-79 Days. Names associated with this variety include Tomato, Tomato Seeds - Determinate - San Marzano Roma, San Marzano Roma.

• Scientific name:Solanum lycopersicum L.
• Life cycle:Annual
• Planting season:Spring
• Growth habit:Determinate
• Plant height:49–60 in
• Sunlight:Full sun
• Seed depth:1/8 in
• Germination:6–12 Days at 75–90 °F
• Spacing:24 in between plants; 36 in between rows
• Soil:Loamy; pH 6.0–6.5
• Water:Moderate
• Support:Trellis
• Reproductive type:Open-Pollinated (OP)
• Fruit:Red; Elongated plum fruit, commonly 3–4 inches.

History and seedkeeping context

San Marzano is a plum-tomato name strongly associated with Campania, Italy, and with sauce making. Different seed companies and growers maintain multiple strains under the name, including determinate and indeterminate garden forms. This listing is the determinate San Marzano Roma strain recorded in the current seed line.

Growing a San Marzano-named tomato outside the legally defined Italian production area does not by itself confer a protected regional designation, so this page describes the garden cultivar and its use without making a protected-origin claim. San Marzano Roma (Determinate Seed Line) is maintained in this catalog as an open-pollinated (op) paste tomato. Published records support the cultivar name and the observable fruit and plant traits used on this page.

Where the available documentation does not preserve a complete breeder, family, or community chain, Species-level tomato domestication in Andean South America is kept separate from the later history of this named cultivar, which may involve farmers, public breeders, gardeners, market growers, and seedkeepers in other regions. The listed heritage classification is Heirloom; it describes the catalog classification and does not prove an undocumented origin story. Public records do not yet establish every detail of the exact San Marzano Roma (Determinate Seed Line) seed line now in circulation.

Observable plant and fruit traits can be described, but a fuller breeder, supplier, accession, or family record should be added only when documentation for this maintained lot becomes available.

Fruit, flavor, and kitchen use

San Marzano Roma (Determinate Seed Line) is best for sauce, roasting, drying, canning, and concentrated tomato cooking. The expected flavor is rich, sweet-savory paste-tomato flavor with dense flesh and restrained juice. Fruit is described as red and elongated plum fruit, commonly 3–4 inches. Use a tested current recipe for home canning; cultivar name alone does not establish safe acidity. San Marzano Roma (Determinate Seed Line) is especially useful for sauce, roasting, drying, canning, and concentrated tomato cooking. Flavor and eating quality are described as rich, sweet-savory paste-tomato flavor with dense flesh and restrained juice. For home canning, use a tested current recipe; cultivar name, color, or perceived sweetness does not establish safe acidity.

How to grow San Marzano Roma (Determinate Seed Line)

Start San Marzano Roma (Determinate Seed Line) indoors about 6 to 8 weeks before the last expected frost. Sow 1/8 in deep in a warm, evenly moist seed-starting mix; expect 6–12 Days near 75–90 °F. Give seedlings strong light, move them into larger cells before they become root-bound, and harden them gradually before planting outside after frost danger.

Plant in full sun with loamy soil near pH 6.0–6.5. Space plants 24 in apart and rows 36 in apart. Maintain moderate moisture, mulch after the soil warms, and keep foliage off wet soil where possible. Set up trellis at transplanting. The determinate plant reaches 49–60 in.

Season care

• Give San Marzano Roma (Determinate Seed Line) strong light from emergence so seedlings remain stocky rather than stretched. • Install trellis when transplanting; adding support after vines are large can damage roots and stems. • Water at the soil line and maintain even moisture to reduce cracking, blossom-end rot risk, and stress-related fruit problems. • Harvest when the fruit has reached its cultivar-specific color and gives slightly to gentle pressure; color alone can be misleading on green, purple, or striped varieties. • Use 70-79 Days as a planning range rather than a guaranteed calendar date; weather and transplant stress can shift first harvest.

Harvest and maturity

70-79 Days from transplanting under suitable conditions. Harvest when the cultivar-specific color has developed and the fruit gives slightly to gentle pressure; green-ripe, striped, purple, and dark cultivars require more than a simple red-color test.

Saving seed

Tomatoes are primarily self-pollinating, but occasional crossing can occur. To maintain San Marzano Roma (Determinate Seed Line), save seed from several healthy true-to-type plants and bag unopened flower clusters when extra isolation is needed. Allow labeled fruit to ripen fully, squeeze the seed and gel into a container, ferment briefly until the gel releases, rinse clean, and dry the seed in a thin labeled layer. Store the finished lot cool and dry with the year, source, plant count, and isolation notes.

Common questions