Auto Dark Purple is an autoflowering cannabis seed from Delicious Seeds that produces deep purple bud clusters in practically 100% of plants. Five generations of selective breeding between the classic OG Kush and a first-gen Purple Kush Auto have locked in the colour, the sweet fruity OG aroma, and a compact indica structure that handles neglect better than most strains you'll meet. If you want purple buds without the faff of a long photoperiod grow, this is one of the easier routes in.
Why Auto Dark Purple earns its name
This is the rare purple strain that actually delivers on the purple promise. Most "purple" autos throw the odd tinted leaf and call it a day — Delicious Seeds spent five generations stabilising the trait, so you're looking at properly dark, almost black-purple bud clusters on nearly every phenotype. According to a 2023 paper on cannabis pigmentation (When Cannabis sativa L. Turns Purple, PMC10376404), cyanidin-3-rutinoside is the major anthocyanin behind that deep colour — the same pigment family you'll find in blackberries and red cabbage.
The genetics read like a purple-lover's shortlist: classic OG Kush crossed with a first-generation Purple Kush Auto, then reworked through five generations to lock in both the sweet, fruity OG flavour and the colour. The autoflowering side keeps things quick — 45 to 55 days from seed to harvest — which is why we keep recommending it to balcony growers and first-timers who don't fancy waiting four months for a photoperiod plant to wrap up.
What to expect from the plant
Auto Dark Purple stays compact with a tidy, even canopy — no wild stretching, no lanky side branches reaching for the ceiling. Outdoors you're looking at 50–70g per plant, which is solid for an auto of this size. The purple leaves also double as camouflage on urban balconies, which is a small but genuinely useful detail if your neighbours have curious eyes.
What makes her easy to grow: high pest resistance, decent mould resistance, and a surprising tolerance for irrigation mistakes. We've seen growers drown autos that lesser genetics would've sulked over — this one shrugs it off. Not bulletproof, but forgiving.
Effect profile
At 18% THC, she's firmly in heavy-indica territory. Expect a sedating, body-led effect with the unmistakable OG Kush flavour lingering on the exhale — sweet, fruity, faintly earthy. Research on phytocannabinoids suggests indica-dominant chemotypes lean toward sedation and physical relaxation (Phytocannabinoids: Pharmacological effects, PMC10658372), which tracks with what Delicious Seeds describes and what growers consistently report back.
Grow specifications
| Seed bank | Delicious Seeds |
|---|---|
| Genetics | OG Kush × Purple Kush Auto (F5) |
| Type | Autoflowering, feminised |
| Indica/Sativa | Indica-dominant |
| THC | ~18% |
| Flowering time | 45–55 days (seed to harvest) |
| Yield (outdoor) | 50–70g per plant |
| Height | Compact — balcony-friendly |
| Flavour | Sweet, fruity OG Kush |
| Resistance | Mould, pests, irrigation stress |
| Pack size | 3 feminised seeds |
How Auto Dark Purple compares to other purple autos
Purple autos are a crowded shelf these days — here's how this one sits against the alternatives we stock.
| Strain | Colour consistency | Finish time | Difficulty |
|---|---|---|---|
| Auto Dark Purple (Delicious Seeds) | ~100% purple phenos | 45–55 days | Easy |
| Typical purple auto hybrids | Variable — often 50–70% | 60–75 days | Easy–medium |
| Photoperiod purple strains | High, cold-dependent | 8–10 weeks flower + veg | Medium |
The honest limitation: autos cap your yield ceiling. If you want monster harvests, a photoperiod purple will outproduce this every time — but you'll wait twice as long and need to manage light cycles. Auto Dark Purple trades peak yield for speed, colour reliability, and a very forgiving grow.
Pairs well with a quality autoflower soil mix and a mild auto-specific nutrient line — autos don't need the heavy feeding schedules photoperiods do. A 60x60 grow tent with an LED around 150–200W is plenty for 1–2 plants of this size.
How to grow Auto Dark Purple
- Germinate seeds in damp kitchen paper between two plates for 24–72 hours, until the taproot reaches about 2–3mm.
- Transplant directly into the final pot (7–11 litres works well). Autos hate being repotted — start them where they'll finish.
- Keep the light cycle at 18/6 or 20/4 from seedling through to harvest. No flip needed — she'll start flowering on her own clock.
- Feed light for the first 2–3 weeks. Autos are sensitive to overfeeding; start at quarter strength and work up.
- Want deeper purple? A cooler night-time temperature (around 15–18°C) in the last 2 weeks pushes anthocyanin production. Colour is partly genetic, partly environmental.
- Flush with plain water for the final 7–10 days before harvest.
- Harvest between day 45 and 55 when trichomes are mostly cloudy with a few amber. Dry slowly at 18–20°C with 55–60% humidity for 10–14 days, then cure in jars.
Frequently Asked Questions
Are purple cannabis strains stronger than green ones?
No — colour and potency are unrelated. Purple comes from anthocyanin pigments (the same family found in blackberries), not from cannabinoids. Auto Dark Purple hits 18% THC because of its OG Kush genetics, not because it's purple.
Is Auto Dark Purple good for beginners?
Yes. It's autoflowering (no light-cycle management), resistant to mould and pests, and tolerant of irrigation mistakes. Compact size makes it suitable for balcony or small tent growing. A genuinely forgiving strain to learn on.
What makes the buds turn purple?
Anthocyanin pigments — specifically cyanidin-3-rutinoside, according to research on cannabis pigmentation (PMC10376404). Delicious Seeds bred for high anthocyanin expression over five generations, and cooler night temperatures in late flower push the colour even deeper.
How much can I expect to harvest?
Around 50–70g per plant outdoors, according to Delicious Seeds. Indoor yields vary with light, pot size, and technique, but expect similar per-plant numbers with good conditions. She's compact — so plan on fitting more plants rather than chasing one giant.
Does the sweet OG Kush flavour really come through?
Yes — that's the trait Delicious Seeds worked hardest to preserve across the five generations of breeding. Expect a sweet, fruity OG Kush profile on both the smell and the exhale, with the earthy Kush undertone staying intact.
How long from seed to harvest?
45 to 55 days total, according to Delicious Seeds. That includes the seedling, veg, and flowering stages combined — autos run on their own clock rather than responding to light cycle changes. One of the quicker purple autos on the market.
Last updated: April 2026
