How to Grow Blue Lagoon Tomato

Wikimedia Commons

Blue Lagoon Tomato

Solanum lycopersicum 'Blue Lagoon'

vegetable

Blue Lagoon is a determinate cherry tomato variety known for its striking deep blue-purple fruits with green shoulders and sweet, complex flavor. The compact plants produce abundant clusters of golf ball-sized fruits throughout the season. This ornamental yet productive variety is ideal for containers and small garden spaces.

When should you plant Blue Lagoon Tomato in your zone?

Get a personalized planting timeline — when to start seeds, transplant, and harvest — based on your USDA zone and local frost dates. Free to start.

Get my Blue Lagoon Tomato timeline →

Example Blue Lagoon Tomato timeline · Pittsburgh, PA (Zone 6b)

Plant Blue Lagoon Tomato
Around Apr 17

Near Pittsburgh's average last spring frost.
Tend & protect
Late spring–summer

Watering, feeding, and pest-watch reminders.
Harvest Blue Lagoon Tomato
Around Jun 21

≈ 65 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Blue Lagoon Tomato dates for your own zip code.

Growing Conditions

☀️

Sun: Full sun, 6-8 hours daily minimum (8+ hours preferred for best fruit production)

💧

Water: Consistent moisture with 1-2 inches per week; water at soil level to avoid fungal diseases. Reduce watering slightly as fruits ripen to concentrate sugars.

📏

Spacing: 18 inches

📅

Days to maturity: 65-75 days from transplant

🌱

Planting depth: 0.25 inches for seeds; transplant at soil line or slightly deeper

Soil

Type: Well-draining loamy soil rich in organic matter

pH: 6.0-6.8

Amendments:

Compost or aged manure Calcium (crushed eggshells or gypsum to prevent blossom end rot) Balanced fertilizer (5-10-10 NPK)

Growing Zones

Find your zone →

Thrives in zones 3-10; excellent choice for cooler climates due to early maturity

2b 3a 3b 4a 4b 5a 5b 6a 6b 7a 7b 8a 8b 9a 9b 10a 10b 11a 11b

Get my Blue Lagoon Tomato timeline →

Growth Stages

Seedling

2-3 weeks

Tiny sprouts with 2 cotyledons (seed leaves) emerge and develop first true leaves. Plants are delicate and light green.

Maintain warm temperatures (70-75°F), consistent moisture without waterlogging, and bright light (grow lights 2-3 inches above seedlings). Thin crowded seedlings.

Vegetative Growth

3-4 weeks

Stocky bushy plants develop multiple branches and dark green foliage. Plants reach 2-3 feet in height with compact, determinate growth habit.

Maintain consistent watering and moderate fertilizing. Support plants with cages or stakes early. Pinch suckers if desired to improve air circulation, though Blue Lagoon tolerates less pruning than indeterminate varieties.

Flowering

2-3 weeks

Small yellow flowers appear in clusters (fascicles) throughout the canopy. Flowers develop on short pedicels characteristic of cherry tomatoes.

Maintain even soil moisture to prevent flower drop. Reduce nitrogen fertilizing and shift to higher phosphorus (flower-promoting) formula. Ensure adequate sun exposure. Temperatures 68-77°F optimize fruit set.

Fruiting

3-4 weeks

Green fruits develop and gradually enlarge. As maturity approaches, fruits transition from green with dark blue shoulders to deep purple-blue throughout. Fruits reach 1-1.5 inches diameter.

Continue consistent watering but allow slight drying between waterings to concentrate sugars. Apply calcium sources if needed. Monitor for pests and disease. Provide support to prevent branch breakage under fruit load.

Ripening & Harvest

Ongoing throughout season (4-8 weeks total production)

Fruits develop maximum color intensity (deep purple-blue or nearly black) and sweetness. Interior becomes deep red with anthocyanin pigmentation.

Fruits may be harvested at color break (when shoulders fully darken) or at full ripeness for peak sweetness. Continue watering consistently. Harvest regularly to encourage continuous production.

Companion Planting

Plan your garden →

Plant with:

Basil Borage Carrots Chives Garlic Lettuce Marigolds Onions Parsley Spinach

Avoid planting near:

Brassicas (cabbage, broccoli, kale) Dill Fennel Other tomato varieties (to prevent cross-contamination of seed)

Common Pests

Hand-pick larvae; encourage parasitic wasps; apply Bacillus thuringiensis (Bt) for heavy infestations
Spray with strong water stream; apply insecticidal soap or neem oil; encourage ladybugs
Increase humidity; spray with water; apply neem oil or sulfur; avoid excessive nitrogen fertilizing
Yellow sticky traps; spray with insecticidal soap; improve air circulation
Remove lower leaves; ensure air circulation; water at soil level only; apply copper fungicide if needed
Remove infected foliage; avoid overhead watering; apply chlorothalonil or copper-based fungicide; improve drainage

Uses

🍳

Fresh eating and salads

Culinary

Blue Lagoon tomatoes offer a sweet, complex flavor with subtle berry notes enhanced by their high anthocyanin content. Their small size and abundance make them ideal for snacking directly from the garden or tossing whole into fresh salads. [source]

🍳

Colorful presentations

Culinary

The striking purple-blue color adds visual interest and nutrition to dishes, cocktails, and garnishes. They can be halved for appetizers or used as edible garnish. [source]

💊

Antioxidant superfood

Medicinal

The deep blue-purple coloration indicates high levels of anthocyanins and other polyphenols, powerful antioxidants with potential anti-inflammatory and cardiovascular health benefits. These compounds are studied for protective effects against various chronic diseases. [source]

🏠

Container gardening

Household

The determinate compact growth habit and prolific fruiting make Blue Lagoon ideal for pots, hanging baskets, and small spaces. A single plant in a 5-gallon container can produce 50-100+ fruits in a season. [source]

🦋

Pollinator attraction

Wildlife

The abundant yellow flowers attract bees and other pollinators throughout the fruiting season, supporting beneficial insect populations in the garden ecosystem. [source]

This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.

Harvest Tips

Harvest when fully dark purple-blue for maximum sweetness and anthocyanin content, or pick at color break to ripen indoors. Fruits continue ripening after picking. Twist or cut gently from stem; leave small stem attached if possible. Harvest regularly (every 2-3 days) to encourage continued flowering and fruiting. Peak harvest occurs 2-4 weeks after first fruit.

Fun Facts

🌱 Blue Lagoon is one of the few naturally blue tomato varieties, owing its color to high anthocyanin content—the same pigment responsible for the blue color in blueberries. This is a naturally occurring trait, not genetic modification.
🌱 Despite their blue exterior, the flesh inside is typically deep red or pink, creating a striking visual contrast when sliced. The flavor develops fully only when the interior ripens to full red color.
🌱 The 'Blue Lagoon' variety was developed through traditional breeding to combine disease resistance with the ornamental and nutritional appeal of blue-pigmented fruits, making it both beautiful and practical for home gardeners.

Gardening Terms

New to gardening? Learn about terms used in this guide:

Full Sun pH Sucker True Leaves

Shop Blue Lagoon Tomato plants and related plants at Plant Addicts →

Join 30,000 gardeners planning their gardens with LizPlants.

Get your personalized Blue Lagoon Tomato planting timeline

Tell us your zip code and we'll calculate exactly when to start Blue Lagoon Tomato seeds, transplant seedlings, and harvest — based on your USDA zone and local frost dates. Includes calendar reminders and printable task lists. Free to start.

Get my Blue Lagoon Tomato timeline →