+ Speed Auto
Cannabis seeds
by Sweet Seeds
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+ Speed Auto Cannabis Seeds by Sweet Seeds
+ Speed Auto is a feminized autoflowering cannabis seed that finishes its entire life cycle in as few as 49 days from germination — making it one of the fastest autoflowers you can grow. Bred by Sweet Seeds from two dedicated autoflower parents (automatic Critical Mass crossed with Speed Devil #2), this strain was selected for one thing above all else: speed. If you want to go from seed to harvest before some growers have even flipped to flower, this is the one.
Why + Speed Auto Seeds Stand Out
Forty-nine days. That's the full lifespan of + Speed Auto — measured in days rather than weeks, as Sweet Seeds puts it. Most autoflowers take 8–10 weeks from germination to chop. This one shaves a solid 2–3 weeks off that timeline without producing the wispy, disappointing plants you'd expect from something this fast.
The genetics tell the story. Automatic Critical Mass brings the yield potential and physical structure — dense, resinous flowers on a compact frame. Speed Devil #2 contributes the ridiculous pace. Both parents are established autoflowering strains, not photoperiod-to-auto conversions that still carry timing inconsistencies. At the core sits Siberian ruderalis genetics, which does two things: triggers automatic flowering regardless of light schedule, and grants natural cold resistance that makes + Speed Auto genuinely reliable in northern European climates and cooler outdoor environments.
Plants stay compact at 50–90 cm, which suits indoor tents, balconies, and discreet outdoor spots equally well. Yields range from 30–150 g per plant depending on conditions, or around 450 g per square metre indoors under optimised lighting. For a 49-day plant, that's seriously respectable output.
The honest limitation? You're not going to get the same yield ceiling as a photoperiod strain that vegs for 6 weeks. That's the trade-off with any autoflower, and it's more pronounced with one this fast. But if you're after multiple harvests per season, a quick turnaround between runs, or you just want something in the jar before summer ends — + Speed Auto earns its name.
What to Expect From + Speed Auto Plants
The finished product is aromatic, enjoyable marijuana with a balanced stone-to-high effect — not purely cerebral, not purely physical, but somewhere in the comfortable middle. Sweet Seeds selected the parent strains for taste as well as speed, so you're not sacrificing smoke quality for the sake of the calendar. Expect a pleasant sweetness on the nose with enough complexity to keep things interesting.
In the hand, the buds are dense relative to plant size. The compact stature means most of the energy goes into flower production rather than stretching upward. If you've grown lanky autos before that put out airy popcorn nugs, + Speed Auto is a different animal — the Critical Mass parentage shows in the flower structure.
Growing + Speed Auto Seeds
This is one of the most forgiving autoflowers for less-than-ideal conditions, thanks to that Siberian ruderalis backbone. Cold snaps that would stress a tropical-leaning strain barely register here. That said, optimal conditions still produce optimal results — here's how to get the most from your 49 days.
| Specification | Detail |
|---|---|
| Seed Type | Feminized Autoflower |
| Breeder | Sweet Seeds |
| Genetics | Auto Critical Mass x Speed Devil #2 |
| Ruderalis Heritage | Siberian ruderalis |
| Life Cycle | 49 days (seed to harvest) |
| Plant Height | 50–90 cm |
| Yield Per Plant | 30–150 g |
| Yield Per m2 | Up to 450 g |
| Effect | Balanced (stone to high) |
| Climate Suitability | Cold-resistant; suited to northern European climates |
| Seeds Per Pack | 3 |
How to Grow + Speed Auto for Best Results
- Germinate your + Speed Auto seeds using the paper towel method or directly in a small pot of moist, airy soil. Taproots typically emerge within 24–72 hours.
- Plant the germinated seed 1–2 cm deep in its final container. Autoflowers don't love transplanting — starting in the final pot (7–11 litres is the sweet spot) avoids root stress that costs you precious days on a 49-day schedule.
- Provide 18–20 hours of light per day throughout the entire life cycle. Autoflowers don't need a light schedule change to trigger flowering, but they do benefit from extended light hours for photosynthesis.
- Keep feeding light during the first 2–3 weeks. These plants are small and fast — heavy nutrients early on cause more harm than good. Introduce bloom nutrients once you see the first pistils, typically around day 20–25.
- Monitor humidity: 60–70% during seedling stage, dropping to 40–50% during flowering to prevent mould on those dense buds.
- Harvest when trichomes shift from clear to milky-white with a few amber ones mixed in. At 49 days, start checking daily from around day 42 — these plants can finish ahead of schedule.
+ Speed Auto vs Other Fast Autoflowers
There are plenty of autoflowers marketed as "fast." Most of them finish in 8–9 weeks, which is standard auto territory. + Speed Auto genuinely delivers in 6–7 weeks (49 days), which puts it in a smaller category. The only strains that come close are other Sweet Seeds speed-bred varieties and a handful of quick autos from competitors — but few match the yield-to-time ratio of 450 g/m2 in under 50 days.
Compared to a standard autoflower like, say, a Northern Lights Auto that takes 10–11 weeks, you could theoretically run two full cycles of + Speed Auto in the same timeframe. For perpetual growers or anyone working with a short outdoor season in the UK, Scandinavia, or the Netherlands, that maths changes everything.
| Feature | + Speed Auto | Typical Autoflower |
|---|---|---|
| Seed to Harvest | 49 days | 60–75 days |
| Height | 50–90 cm | 60–120 cm |
| Yield (per m2) | Up to 450 g | 350–500 g |
| Cold Resistance | Strong (Siberian ruderalis) | Varies |
| Runs Per Season (Outdoor) | 2–3 possible | 1–2 |
Who Should Grow + Speed Auto Seeds
If you're growing outdoors in northern Europe and your summers are short, + Speed Auto is built for you. The Siberian ruderalis genetics mean cooler nights and unpredictable weather won't derail your grow. You can start late, finish early, and still pull a decent harvest.
Indoor growers benefit too — especially if you're running a small tent and want to maximise harvests per year. A 49-day turnaround means you can fit 5–6 full cycles into 12 months if you stagger your starts. Even if you're just impatient (no judgement — we've all been there), there's something deeply satisfying about chopping a plant less than 7 weeks after dropping the seed into soil.
First-time growers also do well with + Speed Auto. The compact size is manageable, the cold resistance forgives environmental mistakes, and the short life cycle means you see results fast enough to stay motivated. If your first grow takes 4 months and fails, you might not try again. If it takes 49 days and succeeds, you're hooked.
Complete your setup with a propagation kit for reliable germination, and grab a jeweller's loupe to check trichome ripeness — on a 49-day plant, timing your harvest window matters more than usual. A compact grow tent in the 60x60 or 80x80 range pairs well with + Speed Auto's modest height.
Frequently Asked Questions
Does + Speed Auto really finish in 49 days?
Yes — 49 days from germination to harvest is the documented life cycle from Sweet Seeds. Some phenotypes may take a few days longer depending on conditions, but 6–7 weeks is realistic. Start checking trichomes from day 42 onward.
Can I grow + Speed Auto outdoors in the UK or northern Europe?
Absolutely. The Siberian ruderalis genetics give + Speed Auto natural cold resistance specifically suited to cooler climates. You can start as late as June and still harvest before autumn sets in, or run multiple cycles across the season.
How much does + Speed Auto yield?
Expect 30–150 g per plant depending on growing conditions, or up to 450 g per square metre indoors. For a 49-day autoflower, that yield-to-time ratio is hard to beat.
Should I transplant + Speed Auto or start in the final pot?
Start in the final pot. With only 49 days of life, any transplant shock costs you growing time you can't get back. A 7–11 litre container works well for the 50–90 cm plants this strain produces.
What light schedule does + Speed Auto need?
Run 18–20 hours of light per day from germination to harvest. As an autoflower, it doesn't require a 12/12 flip to trigger flowering — it flowers automatically based on age, regardless of light schedule.
Is + Speed Auto good for beginners?
It's one of the better choices for a first grow. Compact size, cold tolerance, and a fast life cycle mean fewer things can go wrong — and if something does, you've only lost 7 weeks, not 4 months.
What's the effect like from + Speed Auto?
Sweet Seeds describes it as a balanced stone-to-high effect — not overwhelmingly cerebral or sedating, but a comfortable middle ground. The aromatic, sweet-smelling buds produce enjoyable, well-rounded marijuana.
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.