Tomatoes with anthocyanin-rich skin are real, though most look deep purple or nearly black rather than bright blue. Their color comes from pigments that develop in the skin where fruit receives light. The best-known example, ‘Indigo Rose,’ came from conventional tomato breeding at Oregon State University. It is a cultivated tomato with a striking color trait, not a different species or a laboratory-made plant.
If you are comparing colors and forms across the crop, our guide to the many types of tomatoes puts this unusual color in context.
What makes a tomato blue?
Anthocyanins are water-soluble plant pigments that can look red, purple, or blue depending on the plant tissue and its chemistry. In anthocyanin tomatoes, the pigment builds up mainly in the skin exposed to sunlight. A fruit can therefore have dark blue-purple shoulders and a red or purple-red underside that stayed shaded. Cut one open and you will usually find familiar red flesh beneath the colored skin.
That pattern helps explain why “blue” is a convenient label rather than a promise of an even, sky-blue fruit. Some varieties look violet, deep purple, or almost black on the sunlit side. Other dark tomatoes get their color from different pigments and ripening traits, so a black-looking tomato is not automatically an anthocyanin tomato. The cultivar name and its description matter more than the color shorthand.
How these tomatoes were bred
Tomatoes already make anthocyanins in their leaves and stems, while some wild relatives can color their fruit. Breeders used that naturally occurring variation to bring fruit pigmentation into cultivated tomatoes. Oregon State University’s Jim Myers and his team worked with breeding material whose history included wild tomatoes collected in Chile and the Galápagos Islands. They crossed and selected plants over generations, choosing offspring with useful fruit color and garden qualities.
‘Indigo Rose’ was introduced as an open-pollinated cultivar. The process was conventional crossing and selection, not genetic engineering. Oregon State University describes how breeders selected the cultivar from lines carrying genes from wild tomato relatives. Later work expanded the range of fruit sizes and uses, including cherry and pear-shaped selections and the dark-skinned paste tomato ‘Midnight Roma,’ as Oregon State’s later account of the breeding program explains. These are distinct cultivars, so their shape, flavor, plant habit, and harvest timing can differ. Do not assume every blue tomato shares one parentage or performs identically.
There is also a separate bioengineered purple tomato, so color alone does not tell you how a plant was bred. In a Food and Drug Administration consultation record, its developer describes introducing two genes from snapdragon flowers to increase anthocyanins in the fruit. That is a different breeding route from the conventional crosses used for this cultivar. Check the named variety and its source if breeding method matters to you.
The story is a useful example of how plant breeding works: a breeder can cross useful traits from related plants into a crop, then select repeatedly for a combination that gardeners or growers want. It is still Solanum lycopersicum, the cultivated tomato. Its unusual appearance comes from selected traits within the crop, not from being a tomato-blueberry hybrid.
Blue tomato varieties to know
- ‘Indigo Rose’: A cocktail-sized tomato with dark purple skin on sun-exposed areas and red flesh. It is open-pollinated and a useful reference for understanding this kind of pigmentation.
- ‘Midnight Roma’: A paste-type cultivar bred from ‘Oregon Star’ and ‘Indigo Rose,’ with purple skin suited to fresh eating or processing.
Catalogs and seed sellers may also use “blue” for varieties from independent breeders. Read the description for the actual cultivar, including whether it is open-pollinated or a hybrid, its fruit size, and how the ripe fruit should look. A plant described as open-pollinated can generally be grown from saved seed true to type when it has not crossed with another variety. Seeds from a hybrid may produce offspring that differ from the parent.
Color is only one way to choose a tomato. Fruit shape, texture, and kitchen use may matter more if you want a particular harvest. For a different large, fleshy form, see our guide to oxheart tomatoes.
Choosing seeds and a place to grow them
When shopping, use the named cultivar on the packet or listing rather than relying on a broad color label. “Blue tomato seeds” can refer to different breeding lines, and their ripe color, fruit size, and flavor will not all match. Cornell describes ‘Indigo Rose’ as a compact indeterminate plant with 1 to 2 ounce cocktail-sized fruit, while other cultivars may have a different habit. Check the seed description for support needs and days to maturity for your climate.
Fruit exposed to full sun develops more of the dark skin color, but do not strip leaves just to expose every tomato. Foliage also protects fruit from sunscald, and the shaded side can still ripen to its cultivar’s base color. Follow the seed packet for sowing and transplant timing rather than assuming that all tomato seeds need the same schedule.
When is the fruit ripe?
Do not pick a dark-skinned tomato just because one side has turned dark. Anthocyanin color can develop while the fruit is still unripe, especially on the side facing the sun. With ‘Indigo Rose’ and ‘Midnight Roma,’ useful ripeness cues include a change from glossy blue-purple to duller purple-brown skin and a shift in the shaded bottom from green toward red, as Oregon State Extension explains for these cultivars. The fruit should also be firm with a slight give under gentle pressure, a common harvest cue described by University of Missouri Extension.
Use the cultivar’s own description when growing another type, because ripe base colors can be red, pink, or another shade beneath the dark shoulders. A leaf or calyx can shade part of the fruit, so uneven color does not by itself mean the plant is unhealthy. Give the fruit time to soften and develop its ripe base color instead of waiting for every area to become uniformly blue.
What do they taste like?
There is no single flavor. Anthocyanin pigment is not a flavoring, so a dark tomato still tastes like a tomato. Sweetness, acidity, juiciness, and texture vary by cultivar and growing conditions, just as they do in red tomatoes. Treat tasting notes as cultivar-specific impressions rather than a guarantee for every plant or palate.
Try the first ripe fruit fresh, then decide whether its balance suits salads, sandwiches, or cooking. A paste cultivar such as ‘Midnight Roma’ has a different kitchen role from a small cherry tomato. If sauce and preserving are your priority, compare it with other paste tomato varieties before choosing seed.
Do blue tomatoes have special health benefits?
Anthocyanins are often called antioxidants, and their presence is one reason breeders have studied purple tomatoes. Their presence does not establish that eating this crop prevents or treats disease. Enjoy the fruit for its color and flavor, not as medicine or a substitute for varied produce.
For home gardeners, the practical appeal is straightforward: the dark skin makes a distinctive harvest, and the breeding story is unusual. Choose a named cultivar, check its seed description, and judge ripeness by both color and feel. Once you know which traits you like, you can decide whether to grow the same variety again or try another shape and flavor next season.
