Grandaddy Purple Feminised Seeds

Granddaddy Purple Cannabis Seeds: The Grape & Berry King

If you’re looking to buy Granddaddy Purple Feminised seeds in Australia, this is your ticket to some of the most strikingly gorgeous, purple buds on the planet. Otherwise known as GDP, this legendary 70/30% Indica/Sativa is a Cup-winning classic from San Francisco—prized for her unmistakable grape and berry swagger and a deep sense of calm.

Quick Stats

GDP is a potent, Indica-dominant hybrid (70% Indica / 30% Sativa) with THC levels averaging 17–23% (CBD: <1%). She flowers in 8–10 weeks indoors. Outdoors in Australia: North late March–early April • Mid early–mid April • South mid–late April (into May in cooler years). Matty’s tip: drop night temps by 5-10°C in late flower to bring out her purple hues.

The Legend

Born in 2003, GDP comes from an all-star family: a three-way cross of Mendo Purps, Skunk, and Afghan genetics, bred by renowned cannabis pioneer Ken Estes. He was looking for a potent strain that was as gorgeous as it was powerful. He nailed it—and created a legend that’s still a California classic.

Those deep violet leaves didn’t just make history — they made Instagram before Instagram existed.

Even two decades later, GDP thrives in Aussie setups because of her heat tolerance and short flowering window.

Funny Fact: GDP gets its name because it’s the granddaddy of all the purple strains. Ken Estes bred her to be the original, and she still holds the crown.

Flavour & Aroma

• On the nose: A loud, sweet blast of grape and wild berries with subtle hints of earthy funk.
• On the tongue: A burst of sugary grape and berry sweetness, followed by a floral, earthy exhale with a hint of spice.
• On the linger: sweet hash and grape candy — the kind that clings to your hoodie hours later.

Matty’s Take: “This strain tastes exactly like it smells. It’s a fruity punch to the face—no weird aftertaste, just pure candy-shop goodness.”

Effects & What to Expect

• First wave: An initial, cheeky uplift — that ‘smile for no reason’ buzz.
• Then it settles: A deep, full-body relaxation sets in, washing away stress and leaving you blissful. It’s a mellow, trance-like high—powerful but not a knockout punch unless you overdo it.

Matty’s Take: “After a long day, she’s my go-to. I just put on some music, melt into the couch, and forget about the world for a bit.”

How I Grow It (Matty’s Way)

Skill level: Beginner–Intermediate. She’s forgiving and resilient to pests and mould, which makes her a solid first pick. She stays compact, but a little low-stress training (LST) and topping will boost your yield big time.

Training & support: She’s a bush, not a beanstalk. Top her early to get a wide, flat canopy, and use LST to open up her bud sites for max light penetration.

A GDP-specific quirk for that famous purple: The temperature drop is key, but the real secret is the Nitrogen taper. Reduce your nitrogen input significantly (or cut it completely) one week before the flip. This prepares the plant to fully express its anthocyanin genetics when the cooler night-time temps (5–10°C drop) hit in late flower.

Feeding Philosophy: Remember: she’s a moderate feeder. Keep your pH dialled in (Soil 6.0–6.5; Coco/Hydro 5.5–6.0) to ensure she can actually uptake the nutrients she needs, especially Phosphorus for the colour transition. Ignore the hype — colour comes from calm plants, not drama.

Grow Log: Inside the Tent

Phase/Week	Key Action/Status	Matty’s Tip
Seedling Week 1	First true leaves appear; focus on humidity and warmth.	Keep the dome humid and the light gentle. Don’t drown her—she needs to breathe.
Veg Week 3	Compact, bushy growth; topped (FIM) and started LST.	She loves light—make sure to open her canopy up with LST so every bud site gets sun.
Veg Week 5 (Pre-flip prep)	Final LST before flip; canopy even, airflow tuned.	Do your defol now, mate — she hates a haircut in flower.
Flower Week 4	Buds stacking, with a sugary scent. No real stretch.	Keep airflow up and temps stable. Don’t push her with too much food—she’s not a pig.
Flower Week 7	Colas bulking up; first strong hints of purple in the leaves.	This is your final chance to drop the night temps. It’s the magic trick for those deep colours.
Flower Week 9 (Peak)	Trichomes are milky-white; a few have turned amber.	Start flushing now. A good flush brings out the sweetness and gives a cleaner smoke.
Harvest Week 10 (Colour Chase)	The deep violet expression is maximized. Buds are rock hard.	Drop the night temps to 18°C and watch her blush like a sunset. Chop immediately after the flush.

🚨 RED FLAG: The pH Fiasco (Matty’s Confession)

“I once had a mate who couldn’t figure out why his GDP was turning yellow-brown instead of purple, even though his temps were perfect. The problem? His runoff pH was 7.5. At that high pH, the plant locks out the Phosphorus it desperately needs in flower. The lack of available Phosphorus is what directly prevents the purple anthocyanin pigments from forming, leading to weak colours and burnt tips. Lesson learned: Test your runoff pH every single time. If your runoff’s off, your purple’s gone — simple as that.”

Matty’s Advanced Notes (For the Nerds)

Terpenes & Flavour

• Primary Terps: Myrcene, Caryophyllene, Pinene. This mix creates the deep, calming body effect with spicy and earthy undertones.
• Flavour Hack: Lower the dry room temperature (18°C) during the dry/cure process to help retain the delicate grape esters.

Environment & Feeding

• PPFD: 600–800 µmol/m²/s in bloom. She’ll pack on the weight with strong light.
• EC Target: 1.2–1.4 early veg, 1.6–1.8 in peak flower. Do not push above 2.0; she’ll show nutrient burn with clawed leaves.
• VPD & RH: Aim for 1.0–1.2 kPa in late veg, 1.2–1.5 kPa in flower. Keep RH between 40–50% in flower to prevent moisture build-up.
• Temperature Swing: For max purple expression, aim for a 5–10°C drop in night-time temps during late flower.

Air Management

• Fans & Flow: Keep strong cross-breeze — purple phenos get thicker resin when microclimates break early.

Pests & Resistance

• Pests: Naturally resistant, but dense colas attract caterpillars outdoors — use BT spray weekly in late flower.

🚫 Mythbusting

Myth: “Purple buds are always more potent.”
  Truth (Matty): “Nah, the colour comes from anthocyanin pigments, not THC. The colour is just eye candy, but with GDP, the potency is a bonus.”

Myth: “You have to shock GDP to get it to turn purple.”
  Truth (Matty): “Rubbish. It’s in the genes, mate. You just need to keep her happy and let the natural temperature swings bring out the colour. No need to stress her out.”

Myth: “GDP is a knockout strain that’ll put you to sleep.”
  Truth (Matty): “That’s only if you go full throttle. Start slow, and she’s a calm, chilled-out ride—not an immediate sleep button.”

Myth: “All purple strains are basically the same.”
  Truth (Matty): “Not even close, mate. GDP’s got that grape-berry candy shop flavour locked down — that’s why she’s still the purple queen.”

Myth: “Purple strains can’t handle Aussie heat.”
  Truth (Matty): “GDP’s tougher than she looks — she came from Cali heat, mate. Just give her a cool finish.”

Who It’s For?

Perfect If You:

• Want to grow a beginner-friendly classic with a world-famous look.
• Love a sweet, fruity flavour profile.
• Need a calm, relaxing buzz without being locked to the couch.
• Want to impress your mates with a beautiful-looking plant.

Maybe Not For You If You:

• You’re only chasing pure Sativa energy.
• You hate a strong grape aroma.
• You can’t control humidity in late flower.

🏆 Final Verdict

• World-famous Indica classic with a stunning look.
• Great yield potential and relatively easy to grow.
• Legendary grape and berry flavour is a classic for a reason.
• A balanced, relaxing ride that leaves you clear-headed.

If you’ve never grown purple before, this is where you start.

Matty’s Final Word: “She’s the original purple queen, mate. Grow her right and she’ll pay you back with some of the best-looking and best-tasting buds on the block. Cheers. 🍻”

🙋 We Answer Your Questions (Q&A with Matty)