Costoluto Genovese Tomato — The Deeply Ribbed Old-World Italian
Costoluto Genovese (Solanum lycopersicum ‘Costoluto Genovese’) is the sculpted, deeply fluted tomato that has been a fixture of Ligurian kitchens since the early 1800s. The name says it plainly — costoluto is Italian for “ribbed” — and the flattened, heavily lobed fruit, 170–280 g (6–10 oz) of glossy scarlet, looks almost like a small pumpkin. Under the ribs is dense, richly flavoured flesh with a bold, tangy, old-world taste that Italian cooks prize equally for fresh eating and for cooking down into a robust sauce.
This is a vigorous indeterminate heirloom that fruits all season until frost, and it carries a genuinely useful trait: it keeps setting and ripening through hot weather that shuts down fussier varieties, which is why gardeners in the South and Southwest lean on it. At roughly 80 days from transplant it sits in the mid-season, dependable wherever summers are warm. Give it firm support for the heavy, uneven fruit, steady moisture to keep the ribbed shape from splitting, and full sun, and it produces generously right into cooler autumn weather.
🇺🇸 US: Annual in all zones, and a standout for hot regions — its heat tolerance keeps it producing across the South, Southern Plains, Texas, and California when other heirlooms stall in a scorching July. Thrives across the Midwest and Northeast too.
Best for: rich pasta and pizza sauce, fresh slicing, roasting, and canning.
🌱 How to Grow Costoluto Genovese Tomato Seeds
Start Costoluto Genovese tomato seeds indoors 6–8 weeks before your last frost date, sown 6 mm (¼ in) deep and held at 21–27°C (70–80°F), where they germinate in 5–10 days. Get bright light on the seedlings straight away to keep them stocky, pot up at the first true leaves, harden off over 7–10 days, and transplant only after the last frost with nights above 10°C (50°F).
Plant deep, up to the top leaves, so the buried stem roots out and feeds a vigorous vine. Space plants 60–90 cm (24–36 in) apart in full sun and cage or stake at planting time — this is a big, sprawling indeterminate that carries heavy, uneven fruit and needs firm support. Consistent watering is especially important here: the deep ribbing and lobes make Costoluto Genovese more prone to cracking than a smooth tomato when soil moisture swings, so mulch heavily and water deeply and evenly. Work a calcium source such as bone meal or crushed eggshells into the hole to head off blossom end rot, prune the side shoots to one or two main stems for airflow and larger fruit, and pinch the growing tips about four weeks before your first frost.
🍅 Harvesting & Preserving Costoluto Genovese Tomatoes
Pick Costoluto Genovese when the fruit has coloured to a full glossy scarlet and gives slightly to gentle pressure — the deep lobes ripen a touch unevenly, so let the whole fruit turn before harvesting. Check plants every 2–3 days at peak season and clear ripe fruit to keep the vine setting, especially in heat when it keeps producing. In a heat wave above 32°C (90°F) that stalls colouring, pick at first full blush and finish ripening indoors; never refrigerate a ripe tomato, since cold below 12°C (55°F) dulls the flavour and turns the flesh mealy.
Costoluto Genovese preserves as well as it eats fresh. The dense, richly flavoured flesh cooks down into a robust sauce and cans well whole or crushed, though it runs a little juicier than a dedicated paste tomato, so plan to simmer sauce a bit longer. Halved and slow-roasted, the ribbed fruit concentrates into a deep, tangy base worth freezing in batches. Whole fruit also freezes fine for later cooking.
🍝 Cooking with Costoluto Genovese Tomatoes
Costoluto Genovese is the classic Italian dual-purpose tomato. Its bold, tangy, robust flavour makes an exceptional cooked sauce — this is a traditional base for Ligurian pasta and pizza sauce, roasting down thick and rich with real depth. The dense flesh holds up to long simmering without going watery, and it makes a fine passata or canned tomato.
Fresh, the deeply ribbed fruit is as useful as it is striking. Sliced across the lobes it fans out into a decorative, scalloped round that dresses up a caprese, a sandwich, or an antipasto plate, and its full acidity gives salads and bruschetta a bright, old-world punch. Few tomatoes move so easily from the sauce pot to the salad bowl.
🫙 Saving Costoluto Genovese Tomato Seeds
Costoluto Genovese tomato seeds are rewarding to save because the variety is open-pollinated and grows true to type, keeping that distinctive ribbed shape generation after generation. Use the fermentation method: scoop the seeds and gel into a jar, add a splash of water, and leave at room temperature for 2–3 days until a film forms on top. That fermentation dissolves the germination-inhibiting gel coat and cuts seed-borne disease. Pour off the floaters and pulp, rinse the heavy seeds that sank, and dry them on a plate or screen for 1–2 weeks until they snap rather than bend. Stored cool and dark, they stay viable for 4–5 years.
Two habits protect the line. Save only from open-pollinated Costoluto Genovese, never a hybrid, so the ribbed fruit reproduces true. And because tomatoes occasionally cross when varieties flower side by side, space different types 3–4.5 m (10–15 ft) apart or bag a few flower trusses with fine cloth if purity matters. Before storing a batch, sprout ten seeds on a damp paper towel — if seven or more germinate, the lot is good to keep.
