Costata Romanesco is a traditional Italian heirloom zucchini that has been grown around Rome for generations, prized for flavor that far surpasses modern hybrids. The squat, grey-green fruits feature distinctive fluted ribs that create a scalloped appearance when sliced, making them as beautiful on the plate as they are delicious. Reaching harvest in just 50 to 59 days, this open-pollinated variety thrives in zones 3 through 13 and produces vining plants that need about 36 inches of space to spread. The real reward for gardeners is the rich, nutty flavor that emerges whether you cook these zucchini or eat them raw.
Full Sun
Moderate
3-13
30in H x ?in W
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Moderate
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Grey-green fruits with deep fluted ribs that give them a striking scalloped look when cut, this Italian heirloom delivers a flavor profile that's genuinely different from typical summer squash. The flesh is dense and nutty, excellent both raw and cooked, and the male blossoms are edible and prized in Italian kitchens. Plants grow vigorously but tend to produce less heavily than other squash varieties, so succession plantings every few weeks will keep your harvest steady rather than overwhelming.
Costata Romanesco excels in any preparation where you want the vegetable to shine rather than disappear into the background. Slice it raw into salads to appreciate the crisp texture and nutty depth, or sauté it simply with olive oil and garlic to let the flavor come forward. The male blossoms make an elegant addition to pasta, risotto, or light tempura batters. Because the flavor holds up so well to cooking, this zucchini is especially rewarding in ratatouille, grilled preparations, or any dish where you want vegetables to be the main event rather than just filler.
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Start seeds indoors 3 to 4 weeks before your last spring frost in soil temperatures between 70 and 85°F. This timing allows transplants to be ready just as soil conditions warm outdoors.
Transplant hardened-off seedlings into the garden once all danger of frost has passed and soil has warmed. Space plants 36 inches apart (though 18 inches is an alternative depending on your growing conditions). Handle carefully to avoid damaging the vining roots.
Direct sow seeds outdoors once soil temperature reaches at least 70°F and all frost danger has passed. Plant seeds where you want mature plants to grow, thinning seedlings to appropriate spacing once they develop true leaves.
Harvest Costata Romanesco zucchini when they are small for the best flavor and texture, checking plants every 2 to 3 days once flowering has begun. Pick fruits when the skin is still tender and the flesh inside is dense but not yet seedy; smaller zucchini (typically 6 to 8 inches long) will be superior to overgrown specimens. The distinctive fluted ribs should still feel slightly tender when you squeeze gently. Harvest regularly to encourage continued flowering and fruiting throughout the season.
As a vining annual squash, Costata Romanesco requires minimal pruning beyond removing any obviously dead or damaged foliage. You can gently train the spreading vines to stay within your intended growing space, but avoid aggressive pruning that removes healthy leaves needed for photosynthesis and fruit development.
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“Costata Romanesco carries the name of its origin in the region around Rome, Italy, where it has been cultivated for years as a treasured heirloom. This open-pollinated variety represents centuries of selection by Italian gardeners who valued flavor and distinctive appearance over prolific yield. Unlike modern hybrid squash bred for maximum production and long shelf life, Costata Romanesco was saved and grown because of what it tastes like and how it looks on the plate, making it part of a living tradition of Italian vegetable gardening.”