Grow Paste Tomatoes for Processing

January 15, 2025

By Will Bonsall

Tomatoes are among the most popular garden vegetables, but most of those eaten raw are not paste types. While paste tomatoes are known for their distinct pear shape, the most important feature of all true paste tomato varieties is their relatively low moisture content, which makes them especially suitable for sauce, ketchup, or canning, as opposed to the juicier round tomatoes that are preferred for sandwiches, salad, or out-of-hand snacking. Paste tomatoes also tend to have tougher skins, making them easier to store or ship. The skins aren’t an issue with tomato products, which are typically pureed or cooked for a long time. For home canners, paste types require less cooking time to thicken and fewer bottles.

San Marzano Tomato
The San Marzano tomato is a classic paste tomato, with a pear shape and relatively low moisture content. Amy Leblanc photo

There are dozens — nay, hundreds — of paste tomato varieties, all of which are rather similar-looking, with an elongate shape and dry, meaty flesh. They are associated with Italian cuisine and indeed are often described as “Roma” tomatoes, although Romas are merely one among many paste tomato varieties. There are some varieties called paste (Amish Paste and the various Oxheart types), which, while they may be elongate and have relatively solid flesh, are not the classic Roma shape. The truly classic paste tomato — and the most popular in Italy, I’m told — is San Marzano. Ropreco is also very popular and for good reason, as well as Myona. We don’t actually know Myona’s true identity, but the story is that a seed saver bought the original plants from an Italian greenhouse grower. Therefore, it may well be San Marzano or some other known paste variety, but short of DNA analysis we’ll never know for sure; a superb variety nonetheless. One of my own favorites is Royal Chico, an excellent holding variety that ripens rather uniformly and is great for canning.

Practically everything that applies to growing juicy tomatoes also applies to paste tomatoes in particular. Most paste tomato varieties are determinate, which means when the leading stem reaches a certain growth point, it stops and sends out side branches, making a somewhat bushier form; whereas the indeterminate varieties can just continue to grow upright. That means that paste tomatoes are more or less self-pruning and don’t absolutely require staking, although I often do use 3-to-4-foot stakes just to encourage sunlight penetration and better ripening. Keeping ripening fruit up off the ground also helps to prevent blossom-end rot, as does mulching with hay.

As with all tomato varieties, when saving seed from paste tomatoes, the seed should be fermented to remove the jelly-like amniotic sacs that harbor damping-off spores and generally make the seed less viable. However, paste tomato varieties tend to have fewer seeds and since there is less juice to aid fermentation, it may be helpful to add a little bit of water.

Paste tomatoes lend themselves to companion planting, although I don’t always agree with some of the suggested companions. If the tomato plants are allowed to sprawl, there’s little space for companion plants unless you give them really wide spacing, which for me defeats the purpose. However, if the tomato plants are staked and tied up, and if plants are, say, 4 feet between rows, then an in-between crop might do well. Carrots are often suggested for this, but in my experience, carrots are overly shade-sensitive at that spacing; whereas parsley and cilantro do quite well, acting almost as a living mulch. If the cilantro goes to seed, then it’s still useful as coriander. Basil is also recommended, which is splendid, if the spacing is adequate. (Have you noticed that companion crops that are compatible on your plate are often compatible in the garden? Basil with tomatoes is a prime example.) Several of these crops are also recommended to deter hornworms, though I generally have little trouble with those (don’t hate me, I have no idea why).

I’ve often stored my paste tomatoes by pulling the whole plants, knocking off most of the dirt, and hanging the vines upside down from nails in the cellar beams. Since a large part of my crop is still green at first frost, I strip off the partially ripe fruits, spreading them on screen racks on my glassed-in front porch to sun-ripen. As for the green ones hanging in the cellar, I pick those off as they ripen. Some may drop prematurely onto the dirt floor, but paste tomatoes are tough enough to withstand that. If I’m too preoccupied to process the ripe tomatoes at first frost, one option is to just freeze them — cut up or whole — then thaw and process them at a more convenient time.

This all assumes I’m intending to process and use the tomatoes as sauce or puree, which mostly I do. But I also like to use some as whole tomatoes, much like any other canned fruit. For this I prefer them peeled. Peeling is easily done after the fruits have been parboiled for a few minutes, after which the skins will slip off easily, similar to peaches.

There are still other ways to enjoy paste tomatoes. Due to their low water content, they can be thinly sliced and dried. Air-drying those slices may result in a lot of moldy ones; much better results can be had by using a dehydrator or merely placing trays in an oven with the temperature set low and the door left ajar. Dried tomatoes can be used many ways, but they’re especially appreciated on pizza.

Tomatoes are also delicious stuffed, and paste tomatoes have a large, hollow cavity to hold the stuffing. That cavity is why paste tomatoes are shy seeders.

Just to be clear, paste tomatoes are fine in salads or for out-of-hand snacking; just expect them to be a bit tough-skinned. Likewise, any tomato can be sauced — it just takes more cooking to reduce them to a thick sauce. If you know in the beginning what the intended use of your tomatoes will be, then it’s best to go with the type best suited for that purpose when planting.

About the author: Will Bonsall lives in Industry, Maine, where he directs Scatterseed Project, a seed-saving enterprise. He is the author of “Will Bonsall’s Essential Guide to Radical Self-Reliant Gardening” (Chelsea Green, 2015). And indeed, he is also a distant cousin of another exemplary Maine horticulturist: Tom Vigue. You can contact Bonsall at [email protected].

This article originally appeared in the winter 2024-2025 issue of The Maine Organic Farmer & Gardener.

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