Description
The San Marzano is widely considered the “gold standard” of plum tomatoes. Originally hailing from Peru, it has been grown in the volcanic soils near Mount Vesuvius in Italy since the late 1700s, this heirloom variety is famous for its elongated shape, thick flesh, and remarkably low seed count.
While the UK isn’t exactly the Mediterranean, you can still achieve a spectacular harvest with the right approach.
The Profile
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Type: Indeterminate (Cordon) – requires support.
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Flavour: Rich, complex, and highly savory. It’s less sweet than a cherry tomato but develops a deep “umami” profile when cooked.
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Best For: Canning, sun-drying, and making the ultimate pasta sauce.
Growing Tips for the UK
Our shorter, cooler summers mean San Marzanos need a little extra TLC compared to standard salad tomatoes.
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The Greenhouse Advantage: In the UK, you’ll get much better results growing these under glass or in a polytunnel. If growing outdoors, choose the sunniest, most sheltered spot you have.
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Support: These are vigorous climbers. Use a sturdy cane or string system and regularly tie them in.
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Pinch Out: Remove the “suckers” (side shoots that grow at a 45° angle between the leaf and the stem) to focus the plant’s energy on fruit production.
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Top It Off: In late August, “top” the plant (cut off the growing tip) to ensure the existing green tomatoes ripen before the first frost.
- Feed: Once the first flowers have opened feed weekly with a propriety Tomato fertiliser.
Consistency is Key
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Watering: San Marzanos are prone to Blossom End Rot (black patches on the bottom). This is usually caused by a calcium deficiency triggered by irregular watering. Keep the soil consistently moist, never letting it bone-dry.
Kitchen & Usage Tips
The San Marzano is a “processing” tomato, meaning it truly shines when heat is applied.
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The Perfect Sauce: Unlike juicier tomatoes, San Marzanos have a high dry-matter content. This means they break down into a thick, velvety sauce without needing hours of reduction.
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Easy Peeling: Their skin is relatively thin but tough. To peel, score an ‘X’ on the bottom, blanch in boiling water for 30 seconds, and the skin will slip right off.
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Roasting: If your UK crop isn’t as sweet as you’d like due to a cloudy summer, slow-roast them with olive oil, garlic, and a pinch of sugar to concentrate the flavors.
Pro Tip: Don’t be alarmed by their looks! San Marzanos can sometimes look a bit “pointy” or even slightly hollowed compared to round tomatoes—that’s just the variety’s natural shape.
