100% success rate with these seeds, and a great strain! I tried some seeds from another distributor, and they were all duds. Had a few of these left over, from a few years ago and they grew long tap roots in one day! Very happy with the quality of seeds at the seed pharm.
Austin, on Pineapple Express Feminized Seeds, November 2025
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Autoflower · Purple Urkle x Big Bud
Granddaddy Purple Autoflower Seeds
Granddaddy Purple Autoflower carries the Purple Urkle x Big Bud cross that made GDP a Bay Area classic: deep purple buds, a grape and berry nose and a dense, heavy indica frame. This version flowers on its own clock. Autoflower seeds, indica-dominant at about 70% indica.
- Deep purple. Colour that shows strongest with cool nights
- Grape and berry. A sweet, fruity nose over earth
- Autoflower. No light change needed
$45 away from 10 free seeds and free shipping.
$0$100 · 10 free seeds + free shipping$200 · 20 free
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Shipping is $10, free over $99. Orders over $100 get 10 free seeds, and orders over $200 get 20. Every pack is covered by our 90% germination guarantee. Charged in USD.
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Purple Urkle and Big Bud
Granddaddy Purple came out of the San Francisco Bay Area as a cross of Purple Urkle and Big Bud. Purple Urkle supplies the colour and the grape; Big Bud supplies the weight and the dense, chunky structure. The autoflower version keeps that indica-dominant build, about 70% indica, and adds ruderalis so it flowers on age.
Colour and aroma
The buds turn a deep purple, sometimes almost black at the tips, with orange pistils and a thick frost. Colour is strongest when night temperatures drop a few degrees below the day in the last weeks. The smell is sweet grape and berry over an earthy base, closer to grape candy as the buds cure.
Strain label
Granddaddy Purple Autoflower Seeds · The Seed Pharm- Seed type
- Autoflower Seeds
- Lineage
- Purple Urkle x Big Bud
- Indica / sativa
- Indica-dominant (~70% Indica / 30% Sativa)
- THC
- 20% THC
- Flowering time
- 7-9 weeks
How to grow Granddaddy Purple Auto
Run 18/6 or 20/4 from seed to harvest and sow straight into the final container. The plant grows wide rather than tall, so a light bend of the main stem early on is all the training it needs.
Dense indica buds and cool nights together invite mould, so if you push for colour, push for dry air too. Keep relative humidity moderate in flower and lower it near harvest.
Outdoors, start it once nights are mild. It finishes in summer or early fall, so the colour depends on a cool spell; indoors you can create one.
Read our full Granddaddy Purple seeds review for lineage, grow notes and yield.
Read next: Autoflower outdoor growing · How to germinate seeds · Prairie guide
Granddaddy Purple Auto pack prices
| Pack | Price | Per seed | You save | Bonus seeds | Shipping |
|---|---|---|---|---|---|
| 3 seeds | $39 | $13.00 | Base price | None | $10 |
| 5 seeds | $55 | $11.00 | $10 (15%) | None | $10 |
| 10 seeds | $105 | $10.50 | $25 (19%) | 10 free | Free |
| 20 seeds | $180 | $9.00 | $80 (31%) | 10 free | Free |
Prices in USD. Savings are against the 3-seed price per seed. Bonus seeds are added at checkout once your whole order passes $100, and 20 once it passes $200.
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Granddaddy Purple Autoflower Seeds
Granddaddy Purple Autoflower carries the Purple Urkle x Big Bud cross that made GDP a Bay Area classic: deep purple buds, a grape and berry nose and a dense, heavy indica frame.
From $39
Regular
Granddaddy Purple Regular Seeds
Granddaddy Purple crosses Purple Urkle with Big Bud: grape and berry from one side, big, dense buds from the other.
From $39
Autoflower
Grease Gun Autoflower Seeds
The gassiest autoflower Atlas Seed makes.
From $39Granddaddy Purple Auto questions
Why is Granddaddy Purple so purple?
The colour comes from Purple Urkle. Cool nights in the last weeks bring it out most.
Does the autoflower keep the grape smell?
Yes. Sweet grape and berry over earth, from the same Purple Urkle and Big Bud background.
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