San Marzano Tomato Seed

Why Grow San Marzano Tomato?

World-Renowned San Marzano Paste Tomatoes are a must-grow variety for gardeners who love making their own sauces, salsas, and preserved tomato products. Famous for their exceptional flavor and processing quality, this indeterminate paste tomato produces steadily throughout the season—often right up until the first frost in areas with mild summers. The elongated fruits average about 4 inches long and 1.5 inches in diameter, with a classic shape that’s instantly recognizable.

Perfect Texture and Flavor for Cooking and Preserving San Marzano Tomatoes produce 3.5-ounce fruits with an ideal balance of acidity and rich tomato flavor. Their naturally low moisture content and dense flesh make them especially well suited for thick sauces, tomato paste, salsa, and even drying. Combined with heavy production and reliable performance, San Marzano remains the gold standard paste tomato for home gardeners and cooks who want authentic flavor and professional-quality results from the garden.

San Marzano Tomato Growing Tips

• When to Plant Tomatoes

Tomatoes are a "warm season" vegetable that should be transplanted in the garden once the risk of frost has passed in the early spring months. Start the seeds in a greenhouse or seed starting room approximately 6 weeks before your intended in-ground planting date. Give each of these plants approximately 4' or more of space in your garden.

Timely planting is important for those in southern climates, as hot summer weather can be rough on tomato plants. Gardeners in warmer climates should aim to get their plants in the ground as soon as possible in early spring. Gardeners in areas with milder summers have the advantage of a longer tomato season, and don't have to be as timely with planting.

San Marzano is an indeterminate tomato variety, which means the plants will continue to grow throughout the warm season. When fed well, these plants will get quite large. Be prepared to provide them a tall trellising structure if you want to enjoy the continued production that they offer.

• How to Fertilize Tomatoes

It's always a good idea to apply some pre-plant fertilizer to the soil when planting tomatoes. We like to add a handful Coop Gro organic fertilizer in the planting hole for each tomato plant. This ensures the plants have the right nutrients to put down roots in their new soil.

Fruiting vegetables like tomatoes will benefit from something called "spoon feeding." This process involves frequent fertilizations at lower concentrations, as compared to fertilizing them heavily once.

Once your tomato plants start to grow after transplanting, feed them every 2-3 weeks with a relatively balanced fertilizer. We like to sprinkle Coop Gro around the plants or make a liquid solution of AgroThrive Fruit & Flower and pour that alongside the plants. Tomato plants will also benefit from "hilling" when they grow to approximately 12-18" tall.

*To learn more about how to hill tomatoes, watch this video.

• Harvesting Tomatoes

While there is much hype about the quality and flavor of "vine ripe" tomatoes, allowing tomatoes to ripen on the vine can be a risky proposition. As they ripen, they become susceptible to attacks from birds or pests like tomato hornworms.

As a result, we prefer to harvest our tomatoes when they start to turn pink. We then set them inside on a counter so they can continue to ripen. This does not compromise the flavor, but it does save our tomatoes from being eaten by pests. If you have minimal pest pressure, feel free to let your tomatoes ripen on the vine.