Green Poison XL Auto
Cannabis seeds
by Sweet Seeds
Green Poison XL Auto — Sweet Seeds' Biggest Autoflower Just Got Better
Green Poison XL Auto is a third-generation autoflowering cannabis seed from Sweet Seeds that delivers up to 600g/m² indoors in just 8 weeks from seed to harvest. Built from selectively bred tall-stemmed Green Poison Auto specimens across three generations, this XL version stands roughly 25% taller than the original, develops more bud sites, and produces noticeably more resin. If you want autoflower convenience without sacrificing yield, this is where you start.
Why Green Poison XL Auto Deserves a Spot in Your Grow
We've carried the original Green Poison Auto for years and it's always been a reliable seller — compact, fast, decent output. But the XL Auto genuinely improves on it in the ways that matter. Sweet Seeds took their tallest, most vigorous Green Poison Auto phenotypes and worked them across three generations to lock in the traits growers actually want: more height for more bud sites, thicker resin coverage, and yields that compete with photoperiod strains.
The numbers back it up. Indoors, you're looking at up to 600g/m² under optimal conditions. Outdoors, expect around 250g per plant. She reaches 80–125cm in height — tall enough to develop a proper canopy structure, compact enough to fit in a 60x60 or 80x80 tent without issues. And because she's autoflowering, you don't need to worry about light cycle management. Plant her, give her 20 hours of light daily, and she'll flower on her own schedule.
The honest limitation? At 15–20% THC, she's not going to compete with the 25%+ photoperiod monsters. But that's actually a feature for a lot of growers. The effect is a well-rounded indica-dominant body relaxation with enough sativa influence to keep you mentally present — a proper all-day smoke that doesn't flatten you. We'd pick this over a higher-THC strain that leaves you couch-locked by 3pm.
Green Poison XL Auto Grow Characteristics and Specs
Green Poison XL Auto is a slightly indica-dominant hybrid (56% indica, 44% sativa) that flowers automatically regardless of light schedule. Here's what you need to know before you pop the seed.
| Specification | Detail |
|---|---|
| Seed Bank | Sweet Seeds |
| Seed Type | Autoflowering Feminised |
| Genetics | 56% Indica / 44% Sativa |
| Generation | 3rd Generation Autoflowering |
| THC Content | 15–20% |
| Height | 80–125cm |
| Indoor Yield | Up to 600g/m² |
| Outdoor Yield | Up to 250g per plant |
| Seed to Harvest | Approximately 8 weeks |
| Seeds per Pack | 3 |
Aroma and Flavour Profile of Green Poison XL Auto
This is where Green Poison XL Auto earns its name. The aroma is sweet and fruity with herbal undertones and a hint of earthiness that comes through when you break open a cured bud. It's the kind of smell that fills a room — your carbon filter is going to earn its keep during the final weeks of flowering. The smoke carries that sweetness through, with a smooth inhale and a lingering fruity aftertaste that makes it genuinely pleasant to smoke. If you've grown the original Green Poison Auto, the XL version carries the same terpene profile but denser — more resin means more flavour per hit.
How to Grow Green Poison XL Auto
Growing Green Poison XL Auto is straightforward, even if this is your first autoflower. Here's the process from seed to jar.
- Germinate your seeds using the paper towel method or directly in a small pot of moist, airy soil. Tap roots typically appear within 24–72 hours.
- Transplant seedlings into their final container early — 11–15 litre pots work well. Autoflowers don't love being repotted mid-grow, so get them into their permanent home within the first week.
- Set your light schedule to 20 hours on, 4 hours off for the entire grow cycle. Green Poison XL Auto doesn't need a 12/12 flip — she'll begin flowering automatically around week 3.
- Feed lightly during the first two weeks, then gradually increase nutrients as she enters the vegetative growth phase. Switch to bloom nutrients once you see the first pistils forming.
- Monitor humidity closely during flowering. Keep it below 50% in the final weeks to protect those dense, resinous buds from mould. Good airflow is non-negotiable.
- Harvest around week 8 from germination. Check trichomes with a jeweller's loupe — you're looking for mostly milky with a few amber for that balanced indica-sativa effect.
- Dry in a dark room at 18–20°C with 55–60% humidity for 7–10 days, then cure in glass jars for at least two weeks. Patience here pays off in flavour.
Green Poison XL Auto vs. the Original Green Poison Auto
The question we get asked most: is the XL version actually worth it over the original? Here's the direct comparison.
| Trait | Green Poison Auto | Green Poison XL Auto |
|---|---|---|
| Height | 60–100cm | 80–125cm (approx. 25% taller) |
| Indoor Yield | Up to 450g/m² | Up to 600g/m² |
| Outdoor Yield | Up to 175g/plant | Up to 250g/plant |
| Resin Production | Good | Improved — visibly denser trichome coverage |
| Bud Sites | Standard | Greater number due to extra height |
| THC | 15–20% | 15–20% |
| Seed to Harvest | ~8 weeks | ~8 weeks |
The THC range and flowering time are essentially identical. What you gain is yield and resin — up to 33% more bud indoors, and visibly frostier flowers. If you're growing in a space where you can accommodate the extra 20–25cm of height, the XL version is the better pick. If your tent is under 100cm tall, stick with the original.
Complete your setup: pair Green Poison XL Auto with a proper grow tent and ventilation kit if you're running indoors. For outdoor growers, a set of fabric pots in the 15-litre range gives roots the aeration they need for maximum autoflower performance. And if you want to compare Sweet Seeds genetics side by side, their Crystal Candy XL Auto makes an interesting companion grow — similar speed, completely different terpene profile.
Green Poison XL Auto Effects and Experience
Green Poison XL Auto delivers a balanced effect that leans towards physical relaxation without heavy sedation. The 56% indica genetics bring a warm, full-body calm that settles in within minutes, while the sativa side keeps your headspace clear and lightly uplifted. It's not a "clear the afternoon" smoke — it's more like a volume knob that turns the background noise down a few notches. Good for evenings, but equally workable during a lazy afternoon.
At 15–20% THC, she sits in that sweet spot where experienced smokers get a satisfying session and newer users aren't overwhelmed. The flavour on exhale — sweet, fruity, slightly herbal — makes it easy to reach for again. Traditionally, indica-dominant hybrids like this have been popular among users seeking physical relaxation and appetite stimulation.
Frequently Asked Questions
How long does Green Poison XL Auto take from seed to harvest?
Approximately 8 weeks from germination to harvest. This is one of the fastest turnarounds you'll find for an autoflower producing up to 600g/m². No light schedule changes needed — she flowers automatically.
What is the best light schedule for Green Poison XL Auto?
20 hours on, 4 hours off works best for the full cycle. Some growers run 18/6 to save on electricity, which also produces solid results. Avoid 24/0 — plants benefit from a short dark period for recovery.
How tall does Green Poison XL Auto grow?
Between 80 and 125cm on average. She's roughly 25% taller than the original Green Poison Auto. In a 120cm tent, you'll want to account for pot height and light distance — LST can help manage the canopy if space is tight.
Is Green Poison XL Auto resistant to mould and pests?
She shows good natural resistance to common moulds and pests. However, her dense bud structure means humidity control in the final two weeks of flowering is critical. Keep relative humidity below 50% and maintain good airflow to prevent issues.
Can I grow Green Poison XL Auto outdoors?
Yes — she performs well outdoors and can yield up to 250g per plant. Because she's autoflowering, she doesn't depend on seasonal light changes. Plant her after the last frost and she'll be ready to harvest in about 8 weeks regardless of day length.
What does Green Poison XL Auto smell and taste like?
Sweet and fruity with herbal undertones and a touch of earthiness. The improved resin production in the XL version intensifies the terpene profile compared to the original. Expect a noticeable aroma during late flowering — a carbon filter is recommended for indoor grows.
How does Green Poison XL Auto compare to other Sweet Seeds autoflowers?
She's one of the highest-yielding autos in the Sweet Seeds catalogue at up to 600g/m². Crystal Candy XL Auto is comparable in yield but offers a different flavour profile. For pure indica effects, their Dark Devil Auto is worth a look, though yields are lower.
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.