Green-O-Matic
Cannabis seeds
by Greenhouse Seeds
Green-O-Matic Autoflower Seeds by Greenhouse Seeds
Green-O-Matic is an autoflowering cannabis seed strain from Greenhouse Seeds that delivers up to 700-800g/m² in just 6 weeks of flowering. Built for impatient growers who still want a serious harvest, this compact plant thrives in SOG setups and produces a cerebral, uplifting smoke with 15% THC. If speed and yield are your priorities, this is where you start.
Choose Your Pack Size
Green-O-Matic autoflower seeds come in three pack sizes. The 3-seed pack is a solid test run if you want to see how she performs in your setup before committing. The 5-seed pack covers a decent SOG tray. The 10-seed pack is the one we'd grab — with a 6-week turnaround, you'll want enough seeds to keep rotations going without reordering mid-cycle.
| Pack | Seeds | Best For |
|---|---|---|
| 3 Seeds | 3 | First-time trial run |
| 5 Seeds | 5 | Single SOG tray |
| 10 Seeds | 10 | Continuous rotation grows |
Why Green-O-Matic Autoflower Seeds Deserve a Spot in Your Grow Room
Most autoflowers make you choose: speed or yield. Green-O-Matic refuses that trade-off. In a Sea of Green setup, she pushes out 700-800g/m² in roughly 6 weeks of flowering — numbers that make some photoperiod growers do a double take. The plant stays short and stocky, which means you can pack them tight without canopy management turning into a full-time job.
The 15% THC content sits in a comfortable middle ground. It's not going to flatten you, but it's not decorative either. The smoke hits fast — you'll feel the cerebral lift within minutes — and it sticks around for a good while. Very low CBD and CBN levels mean the body load is almost nonexistent. This makes Green-O-Matic a proper daytime strain: clear-headed, uplifting, and functional. You can smoke a joint at noon and still get things done.
One honest limitation: she doesn't love the cold. If outdoor temperatures drop below 10°C, Green-O-Matic will struggle. But here's the upside of that rapid maturity — outdoors, she only needs 5-6 weeks from start to harvest. In climates where temperatures stay above 10°C from spring through autumn (think Central Europe, April through early November), you can realistically pull multiple outdoor harvests in a single season. That's not marketing fluff; that's just maths.
Green-O-Matic Autoflower Specifications
| Specification | Detail |
|---|---|
| Seed Bank | Greenhouse Seeds |
| Type | Autoflowering |
| Flowering Time | 6 weeks |
| Outdoor Maturity | 5-6 weeks |
| Indoor Yield | 700-800g/m² |
| THC Content | 15% |
| CBD Content | Very low |
| CBN Content | Very low |
| Plant Height | Short / compact |
| Recommended Setup | SOG (Sea of Green) |
| Minimum Outdoor Temperature | 10°C |
| Available Pack Sizes | 3, 5, or 10 seeds |
Running a SOG setup? Pair Green-O-Matic with a proper grow tent and LED panel to maximise that 700-800g/m² potential. A carbon filter is non-negotiable if you're growing indoors — even compact plants produce noticeable aromas during flowering. Check out our grow equipment section for complete tent kits that include ventilation.
Growing Green-O-Matic Autoflower Seeds: What to Expect
We've seen a lot of autoflower strains come through the shop over the years, and the ones that stick around tend to share a trait: they're forgiving. Green-O-Matic fits that mould. She's a short, sturdy plant that doesn't demand constant attention. In a SOG configuration, you're looking at a dense canopy of compact colas — the kind of setup where every square centimetre of your grow space is actually producing.
The 6-week flowering window is genuinely short. For context, most photoperiod strains need 8-10 weeks of flowering alone, plus the vegetative phase. With Green-O-Matic, you're cutting that timeline nearly in half. That speed opens up possibilities: perpetual harvests with staggered planting, or simply getting from seed to jar before impatience sets in. And because she's autoflowering, there's no light schedule to fiddle with — she'll flower regardless of your photoperiod.
The outdoor game is where things get interesting. That 5-6 week maturity means you're not locked into one growing season. Plant a batch in April, harvest in May. Plant again in June, harvest in July. Keep going until temperatures dip below that 10°C threshold. In the Netherlands, that gives you roughly April through October — potentially 3-4 full cycles if you time it right. Just keep an eye on night temperatures in spring and autumn; a cold snap can set her back.
How to Grow Green-O-Matic Autoflower Seeds
- Germinate your Green-O-Matic seeds using the paper towel method or directly in a small pot of moist, airy growing medium. Taproots typically appear within 24-72 hours.
- Transplant seedlings into their final containers early — autoflowers don't recover well from transplant shock, so moving them once while they're still small is better than repotting a mature plant. A 7-11 litre pot works well for SOG setups.
- Provide 18-20 hours of light per day throughout the entire lifecycle. Green-O-Matic is autoflowering, so she doesn't need a 12/12 flip to trigger flowering. More light hours means more energy for bud production.
- Keep indoor temperatures between 20-26°C and humidity around 40-50% during flowering. Outdoors, ensure ambient temperatures stay above 10°C — below that, growth stalls and the plant becomes vulnerable.
- Feed lightly during the first 2-3 weeks, then increase nutrients as flowering begins. Autoflowers are smaller than photoperiod plants and burn easily on heavy feeding schedules. Watch the leaf tips — yellowing tips mean you're pushing too hard.
- In a SOG setup, space plants 15-20cm apart to maximise your canopy coverage. Green-O-Matic stays compact, so tight spacing works in your favour here.
- Harvest after approximately 6 weeks of flowering. Trichomes should be mostly milky with a few turning amber. The fast-hitting, cerebral effect profile is strongest when you harvest at this stage rather than waiting for heavy amber.
Green-O-Matic vs Other Autoflower Strains
Compared to many autoflowering strains on the market, Green-O-Matic stands out on yield. A lot of autos top out around 400-500g/m² — she's pushing 700-800g/m² in optimal SOG conditions. That's a significant difference when you're measuring by the square metre. The 15% THC is moderate; if you want something stronger, look at strains in the 20%+ range, but you'll likely sacrifice that speed. Green-O-Matic's real selling point is the combination of both: she doesn't make you choose between a quick turnaround and a full jar.
If you're comparing within the Greenhouse Seeds catalogue, Green-O-Matic is their speed-focused autoflower. For growers who prefer a longer flowering period in exchange for different terpene profiles or higher potency, Greenhouse offers photoperiod options — but none of them will match this 6-week timeline. It depends on what matters more to you: time or THC percentage. For most home growers running perpetual cycles, we'd pick time.
Frequently Asked Questions
How long does Green-O-Matic take from seed to harvest?
Green-O-Matic reaches full maturity in about 5-6 weeks outdoors, with a flowering period of roughly 6 weeks indoors. Total seed-to-harvest time indoors, including the brief vegetative phase, is approximately 8-9 weeks — one of the fastest turnarounds you'll find in an autoflower.
What yield can I expect from Green-O-Matic autoflower seeds?
In an optimised SOG setup indoors, Green-O-Matic produces 700-800g/m². Actual results depend on your lighting, nutrients, and how tightly you pack the canopy. Even in less-than-ideal conditions, she's a heavy producer for an autoflowering strain.
Is Green-O-Matic suitable for outdoor growing?
Yes, as long as temperatures stay above 10°C. Her 5-6 week outdoor maturity means you can run multiple cycles per season in temperate climates. She's compact enough for balconies and small garden plots, but cold nights will cause problems.
What does Green-O-Matic smoke like?
The effect is cerebral and uplifting — a fast-hitting head high that lasts for hours without dragging you into the sofa. Very low CBD and CBN levels mean minimal body load. It's a solid daytime smoke: clear, functional, and energising rather than sedating.
Do Green-O-Matic autoflower seeds need a specific light schedule?
No. As an autoflowering strain, Green-O-Matic flowers regardless of light schedule. Most growers run 18-20 hours of light per day throughout the full lifecycle to maximise photosynthesis and bud development. There's no need for a 12/12 flip.
Can I grow Green-O-Matic in a small tent?
Absolutely. Green-O-Matic stays short and compact, making her one of the better autoflowers for small spaces. In a 60x60cm tent you can fit 4-6 plants in a SOG arrangement. An 80x80cm tent gives you room for 9-12 plants comfortably.
How does 15% THC compare to other autoflowering strains?
It's moderate. Many autoflowers sit in the 12-18% range, with some newer genetics pushing past 20%. Green-O-Matic's 15% delivers a noticeable and enjoyable cerebral effect without being overwhelming — the trade-off is her exceptional yield and speed, which most higher-THC autos can't match.
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.