Red Poison Auto
Cannabis seeds
by Sweet Seeds
Red Poison Auto by Sweet Seeds — Cannabis Seeds
Red Poison Auto is a feminised autoflowering cannabis seed from Sweet Seeds that produces some of the most visually striking plants you'll ever grow — around 80% of specimens shift from green into deep reddish, lilac, and purple hues during flowering. Descended from a cross between an exotic autoflowering variety with Pakistani Kush ancestry and the legendary Green Poison, this 70% Indica / 30% Sativa hybrid goes from germination to harvest in roughly 8 weeks. The dried buds come out so deeply purple they're almost black. If you want a grow that stops people mid-sentence, this is the seed to start with.
Why Grow Red Poison Auto Seeds
We've seen hundreds of strains come through the shop since 1999, and Red Poison Auto still turns heads every single time someone brings in a photo of their harvest. The colour change is genuinely dramatic — not a subtle tinge of purple you need to squint at, but full-on reddish, lilac, and deep purple buds spiked with pinkish-white hairs. Some plants even push purple pigment into the fan leaves. About 80% of plants express this colouration, so the odds are firmly in your favour, though the remaining 20% stay green. That's genetics for you — not every seed in the pack will turn into an Instagram centrepiece, and it's worth knowing that upfront.
Beyond the looks, this strain is a proper workhorse. The autoflowering genetics mean you don't need to fiddle with light schedules — Red Poison Auto kicks into gear from day one and pushes through vegetative growth and flowering on its own clock. The plants develop a strong central stem with flexible, long branches that fill out nicely. Height ranges from 60 to 120cm depending on conditions, so she fits comfortably in a standard grow tent without needing aggressive training. The Pakistani Kush ancestry shows in the dense, resin-caked bud structure, while the Green Poison parentage brings vigour and yield.
The aroma and flavour of the dried product are intense and pleasant — sweet, earthy, with that deep Kush undertone. But honestly, the real selling point is handing someone a jar of nearly black bud and watching their reaction. That never gets old.
Red Poison Auto Yield and Flowering Time
Red Poison Auto delivers 400-550g/m2 indoors and 35-175g per plant outdoors, finishing in approximately 8 weeks from germination. That's fast, even by autoflower standards.
| Specification | Detail |
|---|---|
| Seed Bank | Sweet Seeds |
| Seed Type | Feminised Autoflower |
| Genetics | Pakistani Kush Auto x Green Poison |
| Indica / Sativa | 70% Indica / 30% Sativa |
| Flowering Time | ~8 weeks from germination |
| Plant Height | 60-120cm |
| Indoor Yield | 400-550g/m2 |
| Outdoor Yield | 35-175g per plant |
| Colour Expression | ~80% of plants turn reddish/lilac/purple |
| Seeds Per Pack | 3 |
The outdoor yield range is wide — 35g to 175g — because autoflowers are sensitive to how much direct light they get. A south-facing balcony in Amsterdam is not the same as a terrace in southern Spain. Indoors under 18-20 hours of light, you'll consistently hit the upper end of that 400-550g/m2 window. The plants respond well to LST (low-stress training) if you want to open up the canopy and push yields further, though the strong central cola on Red Poison Auto is already impressive without intervention.
Red Poison Auto Lineage and Genetics
Red Poison Auto comes from a cross between an exotic autoflowering strain with Pakistani Kush ancestry — responsible for the purple colouration and dense bud structure — and Sweet Seeds' own Green Poison, a proven heavy-yielder with a reputation for vigour. The Pakistani side carries the ruderalis genetics that make this plant autoflower, plus the anthocyanin production that drives those dramatic colour shifts during flowering. Green Poison contributes growth speed, branch flexibility, and resin production.
The 70/30 Indica-to-Sativa ratio shows in the plant structure: compact, bushy, with tight internodal spacing but enough stretch in the branches to avoid a completely squat shape. If you've grown Green Poison photoperiod before, you'll recognise the growth pattern — Red Poison Auto just does it faster and adds the colour show on top.
How to Grow Red Poison Auto Seeds
- Germinate your Red Poison Auto seeds using the paper towel method or by placing them directly into a moist, light soil mix. Taproots typically appear within 24-72 hours.
- Transplant seedlings into their final container early — autoflowers don't love being repotted. A 7-11 litre fabric pot works well. Use an airy growing medium with good drainage; a light mix with perlite is a solid choice.
- Set your indoor light schedule to 18/6 or 20/4 from day one and keep it there for the entire cycle. Red Poison Auto doesn't need a 12/12 flip — she'll start flowering on her own around week 3-4.
- During the first two weeks of vegetative growth, keep feeding light. Half-strength nutrients are enough. The plants develop a strong stem and flexible branches quickly, so give them space to stretch.
- Once flowering begins, switch to bloom nutrients and watch for the colour change. Lower nighttime temperatures (around 15-18°C during dark periods) can encourage more intense purple and reddish pigmentation, though most plants will colour up regardless.
- The dense, resin-heavy buds are ready to harvest roughly 8 weeks after germination. Watch the trichomes — milky with a few amber is the sweet spot. Dry slowly in a dark, ventilated space at 18-21°C for 7-10 days, then cure in jars for at least two weeks.
One honest watch-out: those dense, fat buds can be susceptible to mould in high-humidity environments, especially in the final weeks of flowering. Keep your relative humidity below 50% during late flower and make sure air circulation is decent. A small oscillating fan pointed at the canopy makes a real difference.
Red Poison Auto Compared to Similar Strains
If you're drawn to Red Poison Auto for the colour, Sweet Seeds' Dark Devil Auto is the obvious comparison — it also produces deep purple, nearly black buds with a similar autoflowering timeline. The difference is in the genetics: Dark Devil Auto leans more Sativa in its effect profile and grows slightly taller, while Red Poison Auto's Pakistani Kush backbone gives it a denser, more compact structure and heavier Indica influence. For raw yield, Red Poison Auto edges ahead indoors at 400-550g/m2.
| Feature | Red Poison Auto | Dark Devil Auto |
|---|---|---|
| Genetics | Pakistani Kush Auto x Green Poison | Big Devil Auto x Pakistani auto |
| Indica/Sativa | 70/30 | More Sativa-leaning |
| Indoor Yield | 400-550g/m2 | 350-500g/m2 |
| Height | 60-120cm | 70-130cm |
| Colour | Reddish, lilac, purple, near-black | Deep purple to black |
| Seed-to-Harvest | ~8 weeks | ~8 weeks |
We'd pick Red Poison Auto if you want the Indica-heavy structure and the widest colour palette — the reddish and lilac tones are unique to this strain. Dark Devil Auto is the one if you want an even darker, almost monochrome purple result.
Growing Red Poison Auto indoors? Pair these seeds with a complete grow tent kit to control temperature and humidity — dropping night temps is the trick to maximising that purple colour expression. A carbon filter setup is also worth grabbing; the aroma on this strain is intense once flowering kicks in.
Frequently Asked Questions
Will all Red Poison Auto plants turn purple?
About 80% of Red Poison Auto plants display the reddish, lilac, and purple colour change during flowering. The remaining 20% stay green. It's genetic variation — you can encourage colour expression with cooler night temperatures, but some plants simply won't turn.
How long does Red Poison Auto take from seed to harvest?
Roughly 8 weeks from germination to harvest. That's the full cycle — vegetative growth and flowering included. She's one of the fastest autoflowers we carry at that yield level.
What yield can I expect from Red Poison Auto indoors?
Indoor growers typically get 400-550g/m2 under 18-20 hours of light. Outdoors, expect 35-175g per plant depending on light exposure and climate. The wide outdoor range reflects how much autoflowers depend on direct sunlight hours.
Is Red Poison Auto suitable for beginners?
Yes. Autoflowers don't need light schedule changes, and Red Poison Auto has a strong, forgiving growth structure. The main thing to watch is humidity during late flowering — those dense buds can trap moisture. Keep airflow up and humidity below 50% in the final weeks.
What does Red Poison Auto smell and taste like?
The dried buds have an intense, sweet, earthy aroma with Kush undertones from the Pakistani genetics. The flavour follows suit — rich and pleasant, with a depth that matches the near-black colour of the cured product.
Does Red Poison Auto need special nutrients?
No special feeding required. Standard autoflower nutrients work fine — light feeding in veg, bloom nutrients once flowers appear. She's not a fussy eater. Just don't overfeed in the first two weeks; autoflowers are sensitive to nutrient burn early on.
How tall does Red Poison Auto grow?
Between 60 and 120cm, depending on growing conditions. Indoors under strong light she'll stay more compact. Outdoors with plenty of sun, expect her to push closer to the 120cm mark. Either way, she fits standard grow tents without issues.
Last updated: April 2026
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Medical disclaimer. This content is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare provider before use of any substance.