Blue tomatoes, with their striking anthocyanin-rich skin, are a fascinating example of selective breeding in heirloom varieties. If you’ve seen them at a farmers market or in a seed catalog, you probably had questions. Are they real? Do they taste different? This article explains everything you need to know about these unique fruits, from their history to how you can grow them yourself.
Blue Tomatoes
Blue tomatoes are not a product of genetic modification in a lab. Instead, they are the result of careful, traditional cross-breeding between domestic tomatoes and wild tomato species from South America. The key feature is their high concentration of anthocyanins, the same antioxidants found in blueberries and blackberries. This pigment gives the skin a deep indigo, purple, or nearly black hue, often concentrated on the shoulders where the sun hits.
The Science Behind The Color
The blue color is a sun reaction. The anthocyanins develop in the skin as a natural sunscreen for the fruit. This is why the color is most intense on the top of the tomato. The flesh inside can range from a deep red to a greenish-purple, depending on the specific variety. This natural compound is what makes these tomatoes a topic of nutritional interest.
Anthocyanins and Health
Anthocyanins are potent antioxidants. Studies suggest they may help reduce inflammation and support heart health. While all tomatoes contain beneficial lycopene, blue tomatoes offer this additional antioxidant profile. They are a nutritious addition to any diet.
A Brief History Of Development
The journey to modern blue tomatoes began decades ago. Breeders like Jim Myers at Oregon State University aimed to introduce the anthocyanin trait from wild species like Solanum lycopersicoides and Solanum cheesmaniae into tasty, garden-worthy varieties. The famous ‘Indigo Rose’, released in 2012, was one of the first widely available varieties to come from this research.
Popular Blue Tomato Varieties To Grow
There are now many stabilized blue tomato varieties, each with its own characteristics. Some are better for salads, while others excel as sauce tomatoes. Here is a list of popular choices for home gardeners.
- Indigo Rose: Often the first blue tomato people try. It’s a smaller, salad-sized tomato that turns a deep indigo when ripe. The flavor is tangy and complex.
- Blue Beauty: A larger, beefsteak-style tomato with rich, balanced flavor. It’s known for its reliable production and beautiful dark skin.
- Black Beauty: This heirloom-style variety has very dark, almost black skin and a rich, smoky-sweet flavor that is highly prized.
- Blue Gold Berries: A golden cherry tomato with a blue blush. It offers a stunning color contrast and a sweet, fruity taste perfect for snacking.
- Purple Bumble Bee: A smaller cherry tomato with purple and green stripes. It’s very productive and has a sweet, tangy flavor.
Choosing The Right Variety For Your Garden
Your choice depends on your climate and what you like to eat. For cooler, shorter seasons, early maturing varieties like ‘Indigo Rose’ are a safe bet. If you have a long, hot summer, you can try larger varieties like ‘Blue Beauty’. Always check the seed packet for “days to maturity” to ensure it fits your growing window.
How To Grow Blue Tomatoes Successfully
Growing blue tomatoes is very similar to growing any other tomato. They require the same basic care: sun, water, and support. However, paying attention to a few specific details will help you get the best color and flavor from your crop.
Starting From Seed
For the best selection, you will likely need to start blue tomatoes from seed. Begin seeds indoors 6-8 weeks before your last expected frost date. Use a sterile seed-starting mix and provide plenty of light to prevent leggy seedlings.
- Fill trays with moist seed-starting mix.
- Plant seeds 1/4 inch deep.
- Cover trays to retain humidity until germination.
- Place in a warm location (70-80°F).
- Once sprouted, move to a bright, sunny window or under grow lights.
Planting And Site Selection
Tomatoes need full sun—at least 6-8 hours of direct sunlight daily. This is especially crucial for blue tomatoes, as the anthocyanin development depends on UV light exposure. Choose a well-draining spot and amend the soil with plenty of compost.
- Transplanting: Plant seedlings deeply, burying the stem up to the first set of leaves. This encourages a stronger root system.
- Spacing: Give plants 24-36 inches of space for good air circulation, which prevents disease.
- Support: Install cages or stakes at planting time to avoid damaging roots later.
Care And Maintenance Through The Season
Consistent watering is key. Aim for 1-2 inches of water per week, applied directly to the soil to keep leaves dry. Mulch around plants to conserve moisture and suppress weeds. Fertilize with a balanced organic fertilizer when first flowering, and then switch to a lower-nitrogen fertilizer to encourage fruit set over leaf growth.
Prune suckers (the shoots that grow in the leaf axils) on indeterminate varieties to improve air flow and direct energy to fruit production. Determinate varieties generally do not need pruning.
Encouraging Maximum Color Development
To get that signature blue blush, the fruit needs direct sunlight. Avoid excessive leaf cover over the developing tomatoes. As they mature and start to show color, you can gently shift branches to allow sun exposure. The color develops as the fruit ripens, so be patient.
Harvesting and Storing Your Blue Tomato Crop
Knowing when to pick blue tomatoes can be tricky because the color appears before the fruit is fully ripe. The dark skin can mask the traditional red undertones.
When Are They Actually Ripe?
Do not harvest based on color alone. A ripe blue tomato will have a slight give when gently squeezed, similar to other tomatoes. Look at the bottom of the fruit (the blossom end); it will often soften and show a red or deep purple color underneath the blue. The fruit should also detach easily from the stem with a gentle twist.
Best Practices For Picking And Storage
- Use clean, sharp scissors or pruners to harvest, leaving a small bit of stem attached.
- Handle carefully to avoid bruising the skin.
- For short-term storage, keep them at room temperature away from direct sunlight to preserve flavor.
- Do not refrigerate tomatoes unless they are fully ripe and you need to slow further ripening, as cold temperatures degrade texture and taste.
- For long-term storage, consider canning, making sauce, or drying.
Culinary Uses and Flavor Profile
Many people ask if blue tomatoes taste different. The answer is yes, but in a good way. They often have a richer, more complex flavor than standard red tomatoes. You might detect smoky, tangy, or slightly sweet notes, depending on the variety.
How To Use Them In Your Kitchen
Blue tomatoes are versatile. Their unique color can make familiar dishes visually exciting. However, the dark skin can sometimes turn cooked dishes a muddy brown color, so they are often best used fresh or in preparations where appearance is less critical.
- Fresh Salads and Salsas: Their striking color makes them a beautiful addition to salads and fresh salsas.
- Caprese Salad: Pair with white mozzarella and green basil for a stunning color contrast.
- Sandwiches and Burgers: Add a slice for a burst of rich flavor.
- Roasted or Grilled: Roasting concentrates their flavor beautifully for soups or sauces.
- Preserves: They make excellent, deeply flavored jams and chutneys.
A Simple Blue Tomato Sauce
For a robust pasta sauce, roast halved blue tomatoes with garlic and onions until caramelized. Blend with fresh herbs like basil and oregano. The sauce will have a deep, savory flavor, though it may not retain the bright blue color.
Nutritional Benefits Compared To Red Tomatoes
All tomatoes are healthy, but blue tomatoes offer an extra edge due to their anthocyanin content. Here’s a basic nutritional comparison of what they bring to your table.
- Anthocyanins: The standout nutrient. These antioxidants are linked to reduced oxidative stress and inflammation.
- Lycopene: Still present in good amounts, especially in varieties with red flesh. Lycopene supports prostate and heart health.
- Vitamin C and Potassium: Excellent sources, just like red tomatoes.
- Fiber and Low Calories: A great food for weight management and digestive health.
Including a variety of colored vegetables, including blue tomatoes, ensures you get a wide spectrum of phytonutrients. It’s an easy way to boost the nutritional density of your meals.
Common Questions About Blue Tomatoes (FAQ)
Are Blue Tomatoes Genetically Modified?
No, the blue tomatoes available to home gardeners are not GMOs. They are developed through traditional cross-breeding techniques, selectively combining traits from wild and domestic tomatoes over many plant generations.
Where Can I Buy Blue Tomato Seeds Or Plants?
You can find seeds from many reputable online heirloom and specialty seed companies. Some larger garden centers may carry transplants of popular varieties like ‘Indigo Rose’ in the spring. It’s always best to order seeds early, as they can sell out.
Do Blue Tomatoes Taste Different Than Red Tomatoes?
Yes, they typically have a more complex, richer, and sometimes smokier or tangier flavor profile. They are generally less acidic than some red heirloom varieties, offering a well-balanced taste.
Why Are My Blue Tomatoes Not Turning Blue?
The blue pigment requires sunlight to develop. If the fruit is too shaded by leaves, it may only develop a faint color or stay greenish. Ensure the developing tomatoes receive adequate direct sun exposure for the best color.
Can You Save Seeds From Blue Tomatoes?
Yes, you can save seeds from open-pollinated or heirloom blue tomato varieties. Hybrid varieties (often labeled F1) will not grow true from saved seeds and may revert to different characteristics. Always check your seed packet.
Troubleshooting Common Growing Problems
Blue tomatoes are susceptible to the same issues as other tomatoes. Here’s how to identify and manage common problems.
Pests To Watch For
- Aphids and Whiteflies: Blast them off with a strong jet of water or use insecticidal soap.
- Tomato Hornworms: These large green caterpillars can defoliate a plant quickly. Hand-pick them off.
- Slugs and Snails: Use beer traps or diatomaceous earth around the base of plants.
Disease Prevention
Good garden hygiene is your best defense. Rotate your tomato crops each year, avoid overhead watering, and ensure proper spacing for air flow. Look for disease-resistant varieties when choosing your seeds.
- Early Blight: Causes dark spots on lower leaves. Remove affected foliage and apply a copper fungicide if severe.
- Blossom End Rot: A dark, leathery spot on the bottom of the fruit caused by calcium deficiency and irregular watering. Maintain consistent soil moisture.
- Fusarium Wilt: Plants yellow and wilt from the bottom up. Choose resistant varieties (labeled with an F) and remove infected plants.
Conclusion: Are Blue Tomatoes Worth Growing?
Absolutely. Blue tomatoes offer a unique combination of visual appeal, rich flavor, and enhanced nutrition. They are a conversation starter in the garden and on the plate. While they require the same care as other tomatoes, the reward is a truly special harvest. Whether you’re an experienced gardener or just starting out, adding a plant or two of these unique fruits can make your gardening season more exciting and your meals more colorful. Give them a try and see what all the fuss is about—you might just find a new favorite.