San Marzano is the classic Italian sauce tomato: long, pointed, thick-fleshed and low in seeds and juice. Cooks prize it for sauce, and it grows well in a Kratky system as long as you give it room, because unlike many paste tomatoes it keeps growing all season.
Where San Marzano Comes From
San Marzano is named for San Marzano sul Sarno, a town near Naples in southern Italy, and is traditionally grown in the volcanic soil of the Sarno River valley near Mount Vesuvius. Tomatoes grown there under strict rules can carry the protected designation "Pomodoro San Marzano dell'Agro Sarnese-Nocerino" (DOP). Seeds sold to home gardeners are the same variety type, but only tomatoes grown in that area can use the protected name.
San Marzano at a Glance
| Trait | San Marzano |
|---|---|
| Fruit type | Paste (plum) tomato |
| Shape | Long and narrow with a pointed end |
| Growth habit | Indeterminate (keeps growing and fruiting) |
| Season | Long; fruit ripens over several weeks |
| Best use | Sauce, paste, canning |
| Kratky setup | Large tote, tall support, outdoors or a greenhouse |
San Marzano vs Roma
Both are paste tomatoes, and they look alike, but they grow differently:
- Roma is determinate. It grows to a set height and ripens much of its crop at once, which suits a smaller container and a single canning day. See Roma tomatoes in Kratky.
- San Marzano is indeterminate. It grows tall and keeps producing, so it needs a bigger container, more top-ups and taller support, and it gives a longer harvest.
- Shape and flesh. San Marzano is longer and more pointed, with thicker walls and fewer seeds.
Growing San Marzano with the Kratky Method
- Container: treat it like any vining tomato and start with a 10 gallon tote or larger. See Kratky tomato container size.
- Support: it will outgrow a small cage. An overhead string or a tall stake works best. See pruning and supporting Kratky tomatoes.
- Pruning: remove suckers and keep one or two main stems.
- Water: a tall plant carrying heavy clusters drinks a lot. Top up to the water roots and keep the supply steady, because paste tomatoes are prone to blossom end rot. See topping up a Kratky tomato reservoir.
- Harvest: pick when the fruit is fully red and gives slightly to a gentle squeeze.
Compare San Marzano with other varieties on the tomato varieties for Kratky page.
Frequently Asked Questions
Can you grow San Marzano tomatoes hydroponically?
Yes. San Marzano grows well with the Kratky method in a large container with tall support and regular top-ups.
Is San Marzano determinate or indeterminate?
San Marzano is indeterminate: it keeps growing and fruiting through the season, unlike the determinate Roma.
What is the difference between San Marzano and Roma tomatoes?
Both are paste tomatoes. San Marzano is longer and more pointed, with thicker walls and fewer seeds, and grows as a tall vine; Roma is a compact bush that ripens much of its crop at once.