How to Grow Critical 47
Some crosses are so obvious in hindsight that it is strange someone had to think of them. Critical 47, often shortened to C47, married Critical Mass, the Spanish yield monster, with AK-47, one of the most decorated hybrids of the nineties. The result took home a Spannabis trophy in 2009 and has stayed in grow rooms ever since.
At 15-18% THC, this feminized strain sits comfortably in the medium band, and its 60% indica / 40% sativa balance reads exactly like its effect: happy and talkative at the front, relaxed through the back half. It is sociable flower, the kind that works at a table full of friends rather than on a solo couch. Current pack options are on the Critical 47 seeds page at Blimburn Seeds.
Recommended Strains
Critical 47
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THC | 15% - 18% (Medium) |
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Type | Feminized |
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Yield | High |
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Phenotype | 60% Indica / 40% Sativa |
AK 47
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THC | 16% - 19% (Medium) |
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Type | Feminized |
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Yield | High |
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Phenotype | 35% Indica / 65% Sativa |
Growing it is pleasantly uncomplicated, which is a big part of why the critical 47 strain keeps its following. This guide covers the full run: setup, feeding by EC, the 12/12 flip, and the harvest and cure that do justice to one of the strangest and best flavor profiles in the catalog.
Critical 47 at a Glance
The key numbers from the official datasheet, worth reading before germination day.
| Type | Feminized (photoperiod) |
| Lineage | Critical Mass x AK-47 |
| Award | Spannabis 2009 winner |
| Phenotype | 60% Indica / 40% Sativa |
| THC | 15% – 18% (medium) |
| Climate | Temperate |
| Height | Up to 4.92 ft (1.5 m) |
| Flowering time | 8 – 10 weeks after the flip |
| Harvest month | October |
| Yield indoor | 1.47 – 1.8 oz/ft² (450 – 550 g/m²) |
| Yield outdoor | 2.82 – 4.23 oz/plant (80 – 120 g/plant) |
| Effects | Happy, relaxed, talkative |
| Flavors | Cheese, fruity, hashish, lemon |
Notice the gap between the two yield lines: indoors this plant delivers a generous 450-550 g/m², while the per-plant outdoor figure is a modest 80-120 g. Critical 47 is a compact producer that shines under lights, where its dense bud set fills a canopy; outdoors it stays small and tidy rather than turning into a tree. Plan your setup around that.
Promos & Deals
Why Critical 47 Won Spannabis 2009
Spannabis is the largest cannabis fair in Europe, and its cups are judged by people who see hundreds of entries. For a strain to win in 2009, when Spanish breeding was at the top of its game and Critical crosses were everywhere, meant beating the strongest field imaginable in its own backyard.
What set Critical 47 apart was the combination judges kept coming back to: Critical Mass structure and speed carrying AK-47’s complex aroma, that odd and addictive meeting of sharp cheese, ripe fruit and old-school hashish. Fifteen years on, the award still tells you something useful; this is not a novelty cross but a proven recipe from the award-winning cannabis seeds shelf that earned its place in competition.
Getting Critical 47 Started
Germinate at 70-79°F in a paper towel or starter plug; expect taproots in one to three days. As a photoperiod feminized plant, Critical 47 tolerates transplanting well, so start in a solo cup and pot up to a 3-5 gallon final container as the roots fill each stage. Every seed grows into a flowering female, so what you germinate is what you harvest.
Veg under 18 hours of light at 68-81°F and 50-60% humidity. The AK side gives seedlings a quick, eager start, and the plant settles into the classic Critical pattern soon after: a strong central stem, close internodes and vigorous side branches that practically ask to be trained. Three to four weeks of veg is enough indoors; the plant doubles after the flip and stops around 4.92 ft at most.
Outdoors, plant after the last frost in a sunny, sheltered spot. Remember the compact outdoor profile from the datasheet: this is a container-friendly patio plant that finishes in October, not a hedge, so a 10 gallon pot on a south-facing terrace suits it perfectly.
Feeding Critical 47 by EC
Critical 47 inherits the Critical Mass feeding drive in a slightly politer form. Feed by EC, hold pH at 6.0-6.5 in soil, and it will keep pace without complaint.
| Stage | Weeks | EC | Notes |
|---|---|---|---|
| Seedling | 1-2 | 0.4 – 0.6 | Plain water or very light feed |
| Vegetative | 3-4 | 0.8 – 1.2 | Nitrogen-leaning base nutrients |
| Preflower | Flip + 1-2 | 1.2 – 1.4 | Transition feed through the stretch |
| Bloom | Flip + 3-8 | 1.4 – 1.6 | Bloom base, add PK booster |
| Flush | Final 1-2 | 0.0 – 0.4 | Plain pH-corrected water |
Mid-bloom is where the money is made: hold EC near 1.5-1.6 from week 3 to week 7 after the flip, watch for calcium and magnesium demand under LED lights, and let the fade happen naturally in the final stretch. Overfeeding late is the classic mistake with this strain, because it blunts exactly the cheese-and-fruit funk you grew it for.
Training and Flipping to 12/12
Top once above the fourth node in week 2 or 3 of veg, then use low-stress training to open the plant into an even, bowl-shaped canopy. Those close Critical internodes mean bud sites stack densely along every trained branch, which is how a 4.92 ft plant ends up producing like something much larger.
Flip to 12/12 when the canopy covers about two thirds of the footprint. The stretch is moderate and over within two weeks, after which the plant pours everything into flower for 8-10 weeks. From the first sign of dense bud set, drop humidity to 40-45% and keep air moving through the middle; AK aroma in a Critical-density flower is a gift for you and an invitation for moisture problems if the air stands still.
Harvesting and Curing Critical 47
Check trichomes from week 7 after the flip. Mostly cloudy with scattered amber preserves the happy, talkative character; another week toward amber shifts the weight to the relaxed side. Outdoors in a temperate climate, plants come down in October, conveniently ahead of the worst autumn weather.
Dry for 10-14 days at 59-68°F and around 55% humidity, then cure in glass for at least two weeks. Be warned that the cheese note gets louder in the jar, not quieter; by week three the mix of sharp cheese, lemon and hashish is unmistakable from across the room. Good jars with reliable seals are not optional with this one.
What to Do With Your Trim
Given the hashish note already in the flavor, this strain’s trim practically tells you what it wants to become. Dry-sift it over a fine screen for kief, or run ice water hash for something closer to the old-school texture its aroma promises. Pressed or sprinkled, it tastes like the strain concentrated into its best self.
Aroma, Flavor and Terpenes
Cheese, fruity, hashish and lemon is one of the odder flavor lists in the catalog, and all six listed terpenes pull in the same strange, wonderful direction. Myrcene and caryophyllene build the base: earthy musk and black pepper warmth that read as the hashish layer. Pinene cuts through with a resinous sharpness that keeps the funk from going flat.
Limonene carries the lemon top note, bright and clean against all that depth, while linalool adds the faint floral sweetness that rounds the fruit out. The cheese itself is pure lineage, the signature funk this family has carried for decades, and it emerges strongest after a slow cure. Few strains at this price smell like they cost more; Critical 47 is one of them.
Common Problems and Pro Tips
Critical 47 is a forgiving, high-yielding grow, but its dense Critical buds and low outdoor return are worth planning around.
- Watch the humidity: its dense, stacked Critical Mass buds trap moisture, so keep flowering humidity down and run a fan through the canopy to prevent bud rot.
- Grow it indoors or in a greenhouse: it yields heavily indoors but stays modest outdoors, so a tent or greenhouse gets far more out of this plant.
- Plan for the smell: its cheese and old-school hashish aroma gets pungent in flower, so run a carbon filter if you need to keep the grow discreet.
Expert tip: the vintage cheese, hash and lemon flavour deepens with time. Dry slowly and cure for two to three weeks so that rare, old-school European profile comes through fully.
Frequently Asked Questions
What awards has Critical 47 won?
Critical 47 won at Spannabis in 2009, the largest cannabis fair in Europe, competing against the strongest Spanish breeding of its era. The product page lists it among the award-winning and Spannabis-winning strains in the Blimburn Seeds catalog, a pedigree that still draws growers to it today.
Is Critical 47 an indica or a sativa?
It is a 60% indica / 40% sativa hybrid. The balance shows in the effect: a happy, talkative, social beginning that leans on the AK-47 side, finishing with the relaxed body feel the Critical Mass parent is known for. That mix makes it an easy, sociable strain rather than a heavy one.
How long does Critical 47 take to flower?
Flowering takes 8 to 10 weeks after switching to 12/12 indoors. With a typical three to four week veg, the full indoor run lands near 12 to 14 weeks from seed. Outdoor plants in a temperate climate finish in October, and its dense buds want good airflow through that window.
How much THC does Critical 47 have?
Flowers test at 15 to 18% THC, a medium level that suits its social character. It delivers a noticeable, rounded experience without the overwhelming intensity of modern 25%-plus hybrids, which is precisely why many returning growers keep it in rotation for relaxed, everyday use rather than a knockout high.
How much does Critical 47 yield?
Indoors it produces a generous 1.47 to 1.8 oz/ft² (450 to 550 g/m²) thanks to its dense, stacked bud structure. Outdoors it stays compact, giving 2.82 to 4.23 oz (80 to 120 g) per plant, so indoor and greenhouse setups suit it far better than an open-air grow.
What does Critical 47 taste like?
Sharp cheese and old-school hashish over ripe fruit, with a clean lemon note riding on top. It is a vintage European flavor profile that has become rare in modern catalogs, and it deepens considerably after two to three weeks of curing, so give it that time in the jar.
