How to Grow Colossus Red Pepper

Colossus Red Pepper

Capsicum annuum 'Colossus Red'

vegetable

Colossus Red is a large bell pepper variety known for its massive, blocky fruits that can reach 4-5 inches in diameter. The thick-walled peppers mature from green to a deep red color and are excellent for fresh eating, cooking, and roasting. This cultivar is prized for its productivity and uniform, high-quality fruit.

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Example Colossus Red Pepper timeline · Pittsburgh, PA (Zone 6b)

Plant Colossus Red Pepper
Around Apr 17

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

Watering, feeding, and pest-watch reminders.
Harvest Colossus Red Pepper
Around Jun 26

≈ 70 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact Colossus Red Pepper dates for your own zip code.

Growing Conditions

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Sun: Full sun, 8-10 hours daily (more sun produces larger fruit and better color)

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Water: Consistent moisture; 1-2 inches per week depending on temperature and rainfall. Water deeply at soil level to avoid leaf diseases. Reduce watering slightly once fruit sets.

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Spacing: 18 inches

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Days to maturity: 70-90 days from transplant to first red fruit (green peppers appear earlier)

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Planting depth: 0.25 inches for seeds; transplant at soil level

Soil

Type: Well-draining loamy soil rich in organic matter

pH: 6.0-6.8

Amendments:

Compost or aged manure Peat moss or coco coir Perlite for drainage Balanced fertilizer (5-5-5 or similar)

Growing Zones

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Thrives in zones 5-10; can be grown in zones 3-4 with season extension techniques

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

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Growth Stages

Seedling

4-6 weeks

Small plants with 2-4 true leaves, compact and tender

Start seeds indoors 8-10 weeks before last frost. Maintain 70-80°F soil temperature and 14-16 hours of light daily. Keep soil consistently moist but not waterlogged.

Vegetative

3-4 weeks after transplanting

Rapidly growing plants with multiple branches and dark green foliage, 4-12 inches tall

Transplant to larger pots or garden after last frost when soil has warmed to 60°F+. Harden off for 7-10 days. Provide support stakes early. Apply balanced fertilizer every 2-3 weeks.

Flowering

2-4 weeks

Plants 12-18 inches tall with abundant white flowers appearing in leaf axils

Maintain consistent watering and warm temperatures (70-85°F ideal). Switch to a lower nitrogen fertilizer (higher phosphorus/potassium) to encourage fruit set. Flowers may drop if temperatures exceed 95°F or fall below 55°F.

Fruiting

3-4 weeks

Small green peppers developing from flowers, gradually enlarging to full size (4-5 inches)

Water deeply and consistently; keep soil evenly moist. Mulch around base to retain moisture and regulate temperature. Once peppers reach mature green size, thin to 1-2 fruits per node for larger, higher-quality peppers. Support heavy fruit with stakes or cages.

Ripening & Harvest

2-3 weeks per fruit; can harvest continuously for 8-12 weeks

Peppers transition from dark green to vibrant red, becoming sweeter and more nutritious

Continue consistent watering and feeding. Allow fruits to remain on plant until fully red for best flavor and vitamin content. Harvest green peppers anytime for faster maturation of remaining fruit, or leave on plant for red stage.

Companion Planting

Plan your garden →

Plant with:

Basil Onion Garlic Spinach Parsley Marigold Nasturtium Carrot

Avoid planting near:

Fennel Kohlrabi Brassicas (cabbage, broccoli, cauliflower)

Common Pests

Spray with insecticidal soap or neem oil; encourage natural predators like ladybugs; use reflective mulch
Increase humidity by misting; spray with neem oil or miticide; wash leaves with water spray to dislodge mites
Remove infested fruit immediately and destroy; apply spinosad or pyrethrin; use insect netting in endemic areas
Use yellow sticky traps; spray with insecticidal soap or neem oil; reflective mulch deters them
Row covers on young plants; diatomaceous earth; neem oil spray; remove affected leaves
Use disease-resistant varieties if available; avoid overhead watering; remove infected leaves; practice crop rotation

Uses

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Fresh eating and cooking

Culinary

Colossus Red peppers are excellent raw in salads, sliced for crudités, or cooked in stir-fries, fajitas, and pasta dishes. Their large, thick walls provide substantial flesh perfect for stuffing whole or cutting into large pieces. [source]

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Roasting and grilling

Culinary

The thick walls are ideal for roasting whole over an open flame, grilling, or baking until skin chars. Charred peppers develop deep sweetness and are easily peeled for use in sauces, pestos, and Mediterranean dishes. [source]

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Vitamin C and antioxidants

Medicinal

Red peppers contain significantly more vitamin C and capsanthin (a powerful antioxidant) than green peppers. One Colossus Red pepper can provide over 150% of daily vitamin C requirements and supports immune function, skin health, and anti-inflammatory benefits. [source]

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Food preservation and drying

Household

The large fruits are excellent for drying, roasting and freezing, or making pepper flakes and powders for year-round use. They preserve well in oil, vinegar, or as part of preserved mixed vegetables. [source]

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Pollinator support

Wildlife

Pepper flowers attract bees, butterflies, and other beneficial pollinators, making Colossus Red peppers valuable additions to pollinator-friendly gardens that support ecosystem health. [source]

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

Harvest Tips

For green peppers, harvest when they reach full size (4-5 inches) but still green—use sharp shears or knife to cut, leaving a short stem. For red peppers (sweetest flavor), allow 2-3 more weeks on the plant after reaching full green size. Harvest regularly to encourage continued production. Morning harvest when fruits are firm provides best quality.

Fun Facts

🌱 The 'Colossus' name refers to the exceptionally large, blocky fruit size—among the biggest bell pepper varieties available, making them a showstopper in both the garden and kitchen.
🌱 Peppers change color as they mature because the green chlorophyll breaks down, revealing carotenoid pigments (red, yellow, orange) underneath. Red peppers are essentially mature green peppers and are sweeter and more nutritious.
🌱 Pepper plants are perennial in warm climates and can produce for multiple years; in cold climates, they're grown as annuals, but overwintering potted plants indoors allows year-round production.

Gardening Terms

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

Cultivar Full Sun Mulch pH Transplant True Leaves

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