How to Grow NM Big Jim Pepper

Wikimedia Commons

NM Big Jim Pepper

Capsicum annuum 'NM Big Jim'

vegetable

NM Big Jim is a large, mild chile pepper variety developed by New Mexico State University, known for producing massive 8-10 inch long peppers with thin walls ideal for roasting. This heat-tolerant cultivar produces high yields and has become a staple in southwestern cuisine and home gardens. The peppers mature from green to a deep red color and have a mild, slightly sweet flavor perfect for fresh use, roasting, or drying.

When should you plant NM Big Jim Pepper 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 NM Big Jim Pepper timeline →

Example NM Big Jim Pepper timeline · Pittsburgh, PA (Zone 6b)

  1. Plant NM Big Jim Pepper

    Around Apr 17

    Near Pittsburgh's average last spring frost.

  2. Tend & protect

    Late spring–summer

    Watering, feeding, and pest-watch reminders.

  3. Harvest NM Big Jim Pepper

    Around Jul 1

    ≈ 75 days after planting

Sample dates for Pittsburgh, PA. Sign up to get exact NM Big Jim Pepper dates for your own zip code.

Growing Conditions

☀️
Sun: Full sun, 8-10 hours daily. More sun produces larger, more flavorful peppers.
💧
Water: Consistent moisture; water deeply 1-2 inches per week. More frequent watering during hot, dry periods. Avoid waterlogging and allow soil surface to dry slightly between waterings.
📏
Spacing: 18 inches
📅
Days to maturity: 75-90 days from transplant to first peppers; 100-120 days for full red maturity
🌱
Planting depth: Transplant seedlings 1/4 to 1/2 inch deep; start seeds indoors 8-10 weeks before last frost

Soil

Type: Well-draining loamy soil, rich in organic matter
pH: 6.0-6.8
Amendments:
Compost Aged manure Perlite or sand for drainage Balanced slow-release fertilizer

Growing Zones

Find your zone →

Thrives in zones 5-11, with best performance in zones 7-10. Can be grown in cooler zones (4-6) in warm microclimates or with season extension.

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

Sign up free to see if NM Big Jim Pepper grows in your zone — and get a personalized planting timeline.

Get my NM Big Jim Pepper timeline →

Growth Stages

1

Seedling

4-6 weeks

Small plants with 2-4 true leaves, emerging 7-14 days after seed germination at 70-80°F soil temperature.

Provide bright light (grow lights 2-3 inches above seedlings), maintain moist soil, keep warm, and thin to one plant per cell.

2

Vegetative Growth

4-6 weeks

Robust green plants developing multiple stems and branches, 8-12 inches tall with numerous leaves when ready for transplanting.

Harden off seedlings gradually before transplanting outdoors. Space 18 inches apart. Stake or cage plants to support eventual heavy fruit load. Begin light fertilization.

3

Flowering

3-4 weeks

Small white flowers appear at branch junctions, typically 8-10 weeks after transplanting. Flowers indicate imminent fruit set.

Maintain consistent watering and warmth (65-85°F optimal). Provide balanced fertilizer with adequate potassium and phosphorus. Avoid excessive nitrogen which encourages foliage over flowers.

4

Fruiting & Growth

6-8 weeks

Peppers develop from flowers, quickly elongating to 8-10 inches. Young peppers are dark green, then gradually mature to deep red over 3-4 weeks.

Support heavy fruit with cages or stakes to prevent branch breakage. Maintain regular watering (soil should never fully dry out). Fertilize every 2-3 weeks with balanced or slightly lower nitrogen formula.

5

Harvest

6-12 weeks until frost

Peppers reach full length and color. Green peppers are harvestable in 75-90 days; red peppers develop optimal sweetness after 100+ days.

Harvest green peppers to encourage continued production, or allow to fully mature to red for sweeter flavor. Use pruning shears to cleanly cut peppers. Continue harvesting until first frost.

Companion Planting

Plan your garden →

Plant with:

Avoid planting near:

Fennel Kohlrabi Brassicas (cabbage, broccoli, cauliflower)

Common Pests

  • Spray with neem oil or insecticidal soap; increase humidity; strong water spray to dislodge; introduce predatory mites if severe.

  • Spray with neem oil or insecticidal soap; encourage beneficial insects like ladybugs; remove affected leaves; reflective mulches deter.

  • Use yellow sticky traps; spray with neem oil or spinosad; maintain good air circulation; remove affected flowers.

  • Spray with neem oil or insecticidal soap; use yellow sticky traps; introduce parasitic wasps; increase air circulation.

  • Use cardboard collars around young seedlings; apply diatomaceous earth; handpick at night; eliminate garden debris harboring pupae.

  • Remove and destroy affected fruit; use insecticidal sprays containing spinosad; practice crop rotation; eliminate volunteer pepper plants.

Uses

🍳

Roasting & Chiles Rellenos

Culinary

NM Big Jim peppers are legendary for roasting due to their thin walls and mild flavor. Roast whole over open flame or under broiler to blister the skin, then peel and remove seeds for stuffing with cheese, meat, or vegetables. The peppers are also excellent for fresh consumption, salsa, and southwestern cuisine. [source]

🍳

Drying & Powdering

Culinary

Mature red peppers can be dried whole or in strips to make traditional chile powder and spice blends. The dried peppers store for months and can be rehydrated for sauces or ground into powder for seasoning. This creates a pantry staple with concentrated chile flavor. [source]

🍳

Fresh & Cooked Dishes

Culinary

The mild, slightly sweet flavor makes NM Big Jim versatile for sautéing, grilling, stuffing, or eating fresh. Use in stir-fries, fajitas, sandwiches, or as a vegetable side dish. The large size provides substantial flesh ideal for chunking or slicing. [source]

🏠

Seed Saving

Household

NM Big Jim is an open-pollinated variety, allowing gardeners to save seeds from mature peppers for planting next season. Allow peppers to fully ripen on the plant, then extract, dry, and store seeds in cool, dry conditions for future use. [source]

💊

Nutritional & Health Benefits

Medicinal

Peppers are rich in vitamin C, vitamin A, and antioxidants. Even mild varieties like NM Big Jim provide capsaicin's anti-inflammatory properties and support for cardiovascular and digestive health. Fresh or cooked peppers contribute to a nutritious diet. [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 NM Big Jim peppers when they reach full size (8-10 inches). Green peppers can be picked at 75-90 days for a mild, fresh flavor ideal for roasting and chiles rellenos. For sweeter, deeper flavor and heat (still mild), allow peppers to fully mature to red, which takes an additional 20-30 days. Use clean pruning shears or a sharp knife to cut peppers at the stem, leaving the plant intact for continued production. Harvest regularly to encourage more flowering and fruit set. Stop harvesting 4-6 weeks before the first expected frost to allow the plant to focus energy on ripening remaining peppers.

Fun Facts

  • 🌱 NM Big Jim was developed at New Mexico State University's Agricultural Extension in the 1970s and remains one of the most popular chile pepper varieties in the American Southwest. It was deliberately bred to produce extra-large peppers suitable for commercial and home cultivation in arid climates.
  • 🌱 Despite their impressive 8-10 inch length, NM Big Jim peppers are extremely mild, registering only 900-1,200 Scoville Heat Units (compared to jalapeños at 2,500-8,000 SHU), making them approachable for heat-sensitive palates while still offering authentic chile flavor.
  • 🌱 A single mature NM Big Jim plant can produce 20-40 large peppers in a growing season under ideal conditions, making it an exceptionally prolific and rewarding variety for home gardeners seeking high yields with minimal space.

Gardening Terms

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

Join 30,000 gardeners planning their gardens with LizPlants.

Get your personalized NM Big Jim Pepper planting timeline

Tell us your zip code and we'll calculate exactly when to start NM Big Jim Pepper 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 NM Big Jim Pepper timeline →