Mamba Negra by Blimburn Seeds is a balanced, slightly indica-leaning hybrid with a bright citrus-fruity flavor and a generous, reliable yield. A cross of Critical Mass x Skunk, it is a feminized photoperiod plant with an 18% THC level, citrus and fruity notes, and a versatile, creative, euphoric, uplifting effect. It yields a high 500 g/m² indoors, grows well in many setups, and finishes in 8-10 weeks, which makes it a dependable, flavorful all-rounder. 

This is the standard, THC-rich feminized photoperiod Mamba Negra, distinct from the CBD, CBG, Fast Blooming, and autoflowering versions in the same family. It flowers when you shorten the light cycle, giving full control over veg length, training, and cloning. The figures below are the breeder’s values; check your own pack for the exact numbers. 

Recommended Strains

Mamba Negra cannabis strain bud with tall central cola, dense frosty flowers, orange pistils and dark green serrated leaves on a white background.

Mamba Negra

THC THC 18% (Medium)
Lineage Lineage Critical Mass x Skunk
Type Type Feminized
Height Height 4.92 ft | 1.5 m
Yield Yield High
Yield Indoor Yield Indoor 1.64 oz/ft² | 500 g/m²
Yield Outdoor Yield Outdoor 21.16 - 24.69 oz/plant | 600 - 700 g/plant
Flowering Time Flowering Time 8 - 10 weeks
Phenotype Phenotype 55% Indica / 45% Sativa
Medical Medical Fatigue, Muscle Spasms, Stress
Effects Effects Creative, Euphoric, Uplifted
Flavors Flavors Citrus, Fruity
Mamba Negra Auto cannabis strain with dense, frosty buds, vibrant green leaves, and bright orange pistils on a mature flowering plant.

Mamba Negra Auto

THC THC 8% - 15% (Medium)
Lineage Lineage Mamba negra x Tangie Auto
Type Type Autoflowering
Height Height 4.92 ft | 1.5 m
Yield Yield Medium
Yield Indoor Yield Indoor 1.15 - 1.31 oz/ft² | 350 - 400 g/m²
Yield Outdoor Yield Outdoor 19.4 - 24.69 oz/plant | 550 - 700 g/plant
Life Cycle Life Cycle 8 - 10 weeks
Phenotype Phenotype 80% Indica / 20% Sativa
Medical Medical Arthritis, Insomnia, Pain
Effects Effects Calming, Relaxed, Sleepy
Flavors Flavors Earthy, Fruity, Sweet

Mamba Negra Grow Info 

Trait Mamba Negra (Blimburn) 
Genetics Critical Mass x Skunk 
Seed type Feminized photoperiod 
Genetic profile 55% indica / 45% sativa 
THC 18% (medium) 
Flowering time 8-10 weeks 
Height Around 1.5 m 
Indoor yield High, around 500 g/m² 
Outdoor yield High, around 600-700 g per plant 
Effects Creative, euphoric, uplifted 
Flavor Citrus, fruity 

These are Blimburn’s published figures for Mamba Negra at Growlantis. When you need an exact THC percentage, height, or yield, check the specification on your own Mamba Negra seed pack. 

What Makes Mamba Negra Worth Growing 

Mamba Negra is a reliable, flavorful workhorse. Its Critical Mass and Skunk heritage gives it a bright citrus-fruity flavor, dense productive buds, and a versatile, creative, euphoric, uplifting effect at a comfortable 18% THC. It is a balanced, approachable smoke rather than an overpowering one, good across the day. 

For the grower, its strengths are yield and ease. Its Critical Mass side brings big, dense buds, returning a high 500 g/m² indoors and up to 700 g per plant outdoors on a manageable 1.5 m plant. As a photoperiod it clones well and takes training, so you get full control over a big, citrus-rich, dependable harvest. 

Is Mamba Negra Indica or Sativa? 

Mamba Negra is a balanced hybrid with a slight indica lean, listed at 55% indica and 45% sativa, from its Critical Mass and Skunk parents. 

That near-even split gives it a versatile effect: creative, euphoric, and uplifting from the sativa side with a relaxing body presence from the indica side, so it suits many times of day. The plant has the sturdy, productive structure of its Critical Mass side with a manageable height, and it responds well to training. 

Flowering Time vs Full Grow Time 

Because Mamba Negra is a photoperiod strain, these two numbers are separate, and mixing them up is the most common planning mistake. 

  • Flowering time: 8-10 weeks. This is the bloom stage, which starts only when you switch the lights to 12/12 indoors (or when days shorten outdoors). 
  • Full grow time (seed to harvest): flowering plus however long you veg. Indoors, a typical grow runs around 4 to 5 months from seed, depending on veg length. 

The practical point: you control the total time by choosing your veg length. A longer veg means a bigger plant and harvest; a shorter veg gets you there faster. Outdoors, expect to finish around early to mid October. 

Does Mamba Negra Need a 12/12 Light Cycle? 

Yes. Mamba Negra is a photoperiod strain, so indoors it needs a 12/12 light cycle (12 hours on, 12 hours off) to start and maintain flowering. 

Keep it on a long veg schedule, usually 18/6, for as long as you want it to grow, then flip to 12/12 when it has the size and shape you want. Account for the stretch so it stays under your height limit. Outdoors, shortening late-summer days trigger flowering naturally. If you want a plant that flowers on age instead, that is the separate Mamba Negra Auto. 

Mamba Negra Grow Timeline, Week by Week 

Treat this as a development pattern, not a fixed schedule, since veg length is up to you. 

  • Weeks 1-2: germination and seedling. The taproot and first true leaves establish. Keep humidity up and feeding minimal. 
  • Weeks 3-5: vegetative growth (your choice). The plant builds its frame under 18/6. This is when you top and train. 
  • Week 0 of flower: the flip. Switch to 12/12. Expect a moderate stretch. 
  • Weeks 1-3 of flower: stretch and bud set. Vertical growth finishes and flower sites form. 
  • Weeks 4-8 of flower: bud development. Dense, Critical-Mass-style buds fill out and the citrus-fruity aroma builds. 
  • Weeks 8-10 of flower: ripening and harvest. Judge by trichomes, not the calendar. 
Early cannabis growth in small pots under LED lighting inside a grow tent.

Choosing Your Setup: Space, Light and Pots 

Mamba Negra reaches around 1.5 m with a moderate stretch, so flip to 12/12 while it is comfortably under your height limit. Low stress training or a SCROG net keeps the canopy even and lifts the yield. 

Give it strong light to build its dense, citrus-rich buds. A full-spectrum LED at 30-40 watts per square foot over the flowering canopy keeps the colas full. Add a good inline exhaust fan and a carbon filter, since the citrus-fruity aroma is noticeable in flower. 

For pots, 3-5 gallon containers suit most indoor grows, scaled to veg time and plant size. Fabric pots improve root airflow and help prevent overwatering. 

Germinating and Raising Seedlings 

The paper towel method is the simple, reliable start. Soak the seeds for 12-24 hours, then place them between damp paper towels on a covered plate, kept dark and warm at 70-85°F (21-29°C). A taproot usually appears within two to three days. 

When the taproot reaches about 1-2 cm, plant it root-down a knuckle deep in a light mix and keep the surface moist until the seedling emerges. Hold off on nutrients at this stage. New to growing? Our beginner growing guides cover germination step by step. 

The Vegetative Stage, Topping and Training 

Veg is where you shape a photoperiod plant, and Mamba Negra’s productive, Critical-Mass-driven frame responds well to training. Keep it under 18/6 with a nitrogen-rich feed and build a strong, even frame before you flower. 

Topping the main stem early encourages multiple colas and a wider, flatter canopy, which spreads the high yield. Combine it with low stress training or a SCROG net to expose more bud sites to light. This is also the stage to take clones: cut from a healthy plant in veg to preserve a phenotype you like, since photoperiods clone reliably. Finish training before the flip. 

Feeding and Watering Mamba Negra 

Feed to the stage. Use a nitrogen-forward base through veg to fuel the Critical-Mass vigor, then move to a bloom formula higher in phosphorus and potassium once you flip to 12/12 and buds form. A high-yielding plant handles a solid feed, but start moderate and increase based on how the plant responds rather than overfeeding early. 

Water by root-zone moisture, not a timetable. Let the top inch or two of medium dry between waterings, then water thoroughly until a little drains. Fabric pots and this water-to-weight habit keep the roots healthy and prevent overwatering. 

Flowering and Knowing When to Harvest 

Once you flip to 12/12, expect a moderate stretch, then dense buds fill out over the 8-10 week bloom. The bright citrus-fruity aroma develops, so keep air moving and run a carbon filter indoors, and watch the dense Critical-Mass-style colas for moisture. 

Let ripeness, not the calendar, decide the harvest. Check the trichomes under a loupe and cut when most are cloudy with a few turning amber for the fullest effect. After harvest, hang the branches in the dark at about 60°F (15-16°C) and 55-60% humidity for 7-14 days, then cure in sealed jars, burping daily for the first couple of weeks to protect the citrus flavor. 

Outdoor cannabis farm with tall flowering plants spread across rolling hills.

Growing Indoors vs Outdoors 

Indoors, Mamba Negra rewards control. Hold 18/6 for veg, flip to 12/12, train the canopy even, and the high 500 g/m² yield of dense, citrus-rich flower is very reachable under strong light. 

Outdoors, it is a heavy producer in a warm, sunny climate, returning up to 600-700 g per plant and usually finishing around early to mid October. Its Critical Mass heritage gives big, productive buds. Give it full sun, rich well-draining soil, and strong airflow around the dense buds. 

How Tall and How Much? Height and Yield 

Height is easy to plan for. Mamba Negra reaches around 1.5 m with a moderate stretch, so flip early enough and train to keep the final canopy within your space. 

On yield it is a strong producer, listed as high at around 500 g/m² indoors and 600-700 g per plant outdoors, reflecting its Critical Mass heritage. Strong light, a topped or SCROG canopy, and a healthy root zone are what turn that potential into real weight of dense, citrus-rich flower. 

Best US Climates for Mamba Negra 

Mamba Negra does well in a warm, sunny climate, so growers in California, the Southwest, and warmer Western and Southern states can comfortably take it to an early-to-mid October finish outdoors and its big yield. Its 8-10 week flower also makes it workable in slightly cooler, shorter-season states. 

Its manageable size makes it a strong indoor choice anywhere. In the humid Southeast, keep strong airflow around the dense, Critical-Mass-style buds to prevent rot. For more options, browse our full how-to-grow guide library. 

Common Problems When Growing Mamba Negra 

A few predictable issues are easy to head off. 

Bud rot in dense colas 

Its Critical Mass heritage makes for dense buds that can trap moisture. Keep humidity moderate in late flower and strong airflow through the canopy, especially outdoors. 

Overfeeding 

Start moderate and increase based on the plant’s response, watching the leaf tips for nutrient burn, rather than pushing it too hard. 

Underusing the canopy 

Its productive frame rewards training. Top and spread it to a wide canopy so you capture the full yield rather than one dense central cola. 

Harvesting by the calendar 

The 8-10 week window is a guide, not a cutting date. Read the trichomes and pistils before you cut, since phenotype and environment shift the timing. 

Making the Most of Your Harvest 

Do not waste the trim. The resinous sugar leaves make good bubble hash, dry sift, or rosin that keeps the citrus-fruity character. The stems, roots, and fan leaves compost well and feed your next grow. 

Is Mamba Negra Right for You? 

If you want a dependable, high-yielding, balanced hybrid with a bright citrus-fruity flavor and a versatile, creative effect, yes. Its yield, flavor, and easy balance make it a reliable all-rounder. If you want a high-CBD or high-CBG version, a plant that flowers on age, or maximum THC, consider the Mamba Negra CBD, CBG, Auto, or another strain. Browse our full how-to-grow guide library for more. 

Cannabis seedlings in trays receiving gentle mist under warm light.

Frequently Asked Questions 

Is Mamba Negra indica or sativa? 

Mamba Negra is a balanced hybrid with a slight indica lean, listed at 55% indica and 45% sativa, from its Critical Mass and Skunk parents. The effect is creative, euphoric, and uplifting with a relaxing body presence, so it suits many times of day. The plant has the sturdy, productive structure of its Critical Mass side with a manageable height. 

How long does Mamba Negra take to flower? 

Mamba Negra flowers in 8 to 10 weeks once you switch to 12/12. Total seed-to-harvest time depends on your veg length, usually around 4 to 5 months indoors. Outdoors it finishes around early to mid October. Judge the finish by trichome maturity rather than the calendar, since phenotype and conditions shift the exact timing. 

Does Mamba Negra need a 12/12 light cycle? 

Yes. It is a photoperiod strain, so indoors it needs a 12/12 light cycle to flower. Keep it on 18/6 during veg, then flip when it has the right size. Outdoors, shortening late-summer days trigger flowering. If you want a plant that flowers on age, grow the Mamba Negra Auto instead. 

How much does Mamba Negra yield? 

Mamba Negra is a high yielder, producing around 500 g/m2 indoors and 600 to 700 g per plant outdoors, reflecting its Critical Mass heritage. Strong light, a topped or SCROG canopy, and a healthy root zone are what turn that potential into real weight of dense, citrus-rich flower. 

How strong is Mamba Negra? 

Mamba Negra is moderately potent at 18% THC, listed as medium. The effect is balanced, creative, euphoric, and uplifting with a relaxing body presence, approachable and versatile rather than overwhelming. Its bright citrus-fruity flavor and big, dependable Critical Mass yield are a big part of its appeal alongside the comfortable strength. 

What is the difference between Mamba Negra and Mamba Negra CBD? 

The standard Mamba Negra in this guide is the THC-rich version at 18% THC, grown for a balanced recreational effect. Mamba Negra CBD is a separate, CBD-rich version with minimal THC for a calmer character, and there are also CBG, Fast Blooming, and autoflowering versions. Pick the one that matches the profile you want. 

What does Mamba Negra taste like? 

Mamba Negra has a bright citrus and fruity flavor from its Critical Mass and Skunk heritage. To protect those terpenes, run a carbon filter in flower, dry slowly at around 60F with moderate humidity, and cure in sealed jars, burping daily for the first two weeks. A careful cure keeps the citrus-fruity character fresh and full.