How to Grow Granddaddy Purple
Granddaddy Purple is a legendary, indica-dominant feminized strain that crosses Purple Urkle with Big Bud. It is a 70/30 indica with a high 25% THC, a sweet berry and fruity flavor, and a happy, relaxed, talkative effect. Famous for its deep purple buds and rich grape-berry aroma, it pairs classic looks with heavy yields, making it a rewarding strain to grow.
As a feminized photoperiod strain, Granddaddy Purple lets you control the grow: you keep it in vegetative growth under long days for as long as you like, then switch the lights to trigger flowering. It finishes flowering in about 8 to 10 weeks, and outdoors it is ready to harvest in October, giving you a compact, high-yielding plant with striking purple colors and a sweet, berry-forward profile.
Recommended Strains
Granddaddy Purple
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THC | 25% (High) |
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Type | Feminized |
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Yield | High |
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Phenotype | 70% Indica / 30% Sativa |
Granddaddy Purple Auto
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THC | 16% - 19% (Medium) |
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Type | Autoflowering |
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Yield | High |
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Phenotype | 80% Indica / 20% Sativa |
Potent, beautiful and beginner-friendly, Granddaddy Purple is a rewarding strain to grow. You can see the full genetics and buy Granddaddy Purple seeds on the strain page, and browse the rest of our feminized seeds alongside it.
Strain Profile at a Glance
| THC | High (25%) |
|---|---|
| Lineage | Purple Urkle x Big Bud |
| Type | Feminized |
| Genetics | 70% Indica / 30% Sativa |
| Climate | Temperate |
| Flowering time | 8-10 weeks |
| Harvest | October (outdoors) |
| Height | 4.92 ft / 1.5 m |
| Yield indoor | 1.47-1.64 oz/ft² (450-500 g/m²) |
| Yield outdoor | 21.16-24.69 oz/plant (600-700 g/plant) |
| Grow difficulty | Easy, beginner-friendly |
| Flavors | Berry, Fruity |
| Effects | Happy, Relaxed, Talkative |
Promos & Deals
Vegetative Growth and Flipping to Flower
Granddaddy Purple is a feminized photoperiod strain, so it flowers in response to the light cycle rather than on its own schedule. You keep it in vegetative growth under long days, usually 18 hours of light to 6 of darkness, for as long as you want to build its size and structure. This is where you set the frame of the plant, so give it room, healthy roots and steady feeding before you make the switch.
When the plant is the size you want, you flip the lights to a 12/12 cycle, 12 hours of light and 12 of darkness, to trigger flowering. From that point it takes about 8 to 10 weeks to finish. Because it is a compact, indica-dominant plant that stays around 1.5 m, it responds well to light training during veg: gently opening the canopy early helps light reach more bud sites and lifts your final yield.
Climate and Where to Grow It
Granddaddy Purple suits a warm, temperate climate and grows well both indoors and outdoors where it gets strong light and steady conditions. Because it is a photoperiod plant, outdoor growers should time it so it finishes in October, while indoor growers can run it year-round under a controlled light cycle. A cooler finish, with chilly nights late in flowering, is often what brings out its deepest purple colors.
Its high 25% THC places it firmly among our high-THC seeds, and its compact, indica-dominant structure sits naturally in our indica seeds. You can explore both of its parents directly through the Purple Urkle and Big Bud pages to see where its color and its heavy yields come from.
On yield it is a heavy producer, giving around 450-500 g/m² indoors and a large 600-700 g per plant outdoors, so there is real weight here to go with the looks and potency. Keep temperatures around 68-80°F (20-27°C) and the humidity steady through flowering so the dense, colorful buds ripen clean in its temperate window.
Feeding Schedule (EC Guide)
Granddaddy Purple is a vigorous, heavy-yielding plant that can take a moderate to full feed, but build up gradually rather than pushing it from the start. Feed it steadily through veg, shift toward bloom nutrients as it starts flowering, then flush at the end so the berry and fruity notes come through clean. The ranges below are a starting guide; adjust to your water and medium.
| Stage | EC (mS/cm) | Notes |
|---|---|---|
| Seedling | 0.5-0.7 | Light feed while roots establish |
| Vegetative | 1.2-1.6 | Build nitrogen as the plant grows |
| Early flower | 1.6-1.9 | Shift toward bloom nutrients (P and K) |
| Full flower | 1.8-2.1 | Peak bloom feed for heavy, dense buds |
| Flush | 0.0-0.4 | Plain water for the final 1-2 weeks |
Flowering and Harvest
Once flipped to 12/12, Granddaddy Purple flowers for about 8 to 10 weeks, and outdoors it is ready around October. It builds dense, chunky buds that often turn deep purple as they ripen, developing a sweet berry and grape aroma over a rich, fruity base. Those striking purple colors and heavy, resinous flowers are the signature it inherits from Purple Urkle, and they are a big part of why the strain is so loved.
Yields are heavy, around 450-500 g/m² indoors and 600-700 g per plant outdoors on a well-grown specimen, so there is real weight to go with the beauty. Keep the dense colas supported and the canopy open so light reaches the lower sites, feed it well through flower, and harvest when most of the trichomes have turned cloudy with a few amber for the fullest berry, fruity flavor and the most relaxing effect.
Drying and Curing
Dry whole plants or branches in a dark room at around 60°F (15-18°C) and 55-60% humidity for 7-14 days, until the thin stems snap rather than bend. A slow, even dry matters with such dense buds, because they can stay damp in the middle while the outside dries, and a gentle dry protects both the sweet berry aroma and the deep purple colors that define the strain.
Then cure the trimmed buds in sealed jars, burping them daily for the first week and letting them settle for three to four weeks. A proper cure is what brings out the full berry, fruity character and smooths the smoke, turning a freshly dried harvest into the rich, grape-sweet result Granddaddy Purple is famous for.
What to Do With Your Trim
Don’t bin the sugar leaves you remove while manicuring. Granddaddy Purple is a resinous plant, so its trim is excellent for dry sift, bubble hash or rosin. That resin and its sweet, berry aroma make the trim genuinely valuable, turning offcuts into a potent, flavorful concentrate run rather than waste, a real bonus from such a heavy-yielding, high-THC strain.
Flavor and Terpenes
Granddaddy Purple leads with a sweet berry and grape flavor over a rich, fruity base, the classic profile it inherits from its Purple Urkle parent. It is a smooth, full-bodied smoke, and a good cure brings that berry-fruity character forward in the jar and on the inhale, with the deep fruit sweetness giving it its signature taste.
Its terpene profile frames that flavor. Linalool brings a soft, gently floral note that rounds out the berry sweetness, while camphene adds a cool, woody, slightly herbal edge underneath. The sweet berry and grape notes themselves come through strongly from its Purple Urkle genetics, with these terpenes building a soft, floral, woody frame around that rich, fruity core.
Effects and Best Use
With its high 25% THC and indica-dominant 70/30 make-up, Granddaddy Purple delivers a potent, well-rounded experience. It is reported as happy, relaxed and talkative, pairing an upbeat, good-natured lift with a comfortable, settled body. The potency is genuinely high, so a measured dose goes a long way, especially for newer smokers who may prefer to start slow and build up.
That happy, relaxed, talkative profile makes it a natural choice for the late afternoon or a social evening, well matched to its sweet berry, fruity flavor. The combination of real potency, beautiful purple buds and a comfortable, easy-going body is exactly why Granddaddy Purple has stayed a beloved classic among indica-dominant strains.
Common Problems and Pro Tips
Granddaddy Purple is forgiving and beginner-friendly, but its dense buds ask for a clean, airy finish. In flowering, keep the air moving and the humidity steady so those tight, chunky colas ripen without trapping moisture at the heart of the bud. With buds this dense, good airflow through the final weeks is the main thing that keeps the harvest clean.
For the deepest purple color, let the plant see cooler nights in late flowering, since a drop in night temperature is what brings out its signature hues, though the color is genetic and will show to some degree regardless. Training also pays off: light topping and low-stress training during veg open the canopy and spread the bud sites, which lifts your final yield on this already heavy producer.
As a pro tip, support the dense colas as they fill out so the branches do not strain under the weight, then flush properly at the end so the berry and fruity notes come through clean. Protect the terpenes and color with a careful dry and a full three to four week cure, save the resinous trim for concentrates, and harvest when most trichomes are cloudy with a few amber for a rich, flavorful result.
FAQ
Is Granddaddy Purple a feminized strain?
Yes. Granddaddy Purple is a feminized photoperiod strain, so it produces female plants and flowers in response to the light cycle. You keep it under long days to grow its size, then flip the lights to a 12/12 cycle to start flowering. That control lets you dial in exactly how big the plant gets before it blooms, which suits any grow space.
How much THC does Granddaddy Purple have?
Granddaddy Purple is a potent, high-THC strain, testing around 25% depending on the phenotype and how it is grown. Combined with its indica-dominant 70/30 genetics, the result is a happy, relaxed, talkative effect with a comfortable body. It is well worth dosing carefully if you are newer to strong strains, since the potency is genuinely high.
Why does Granddaddy Purple turn purple?
Granddaddy Purple gets its deep purple color from its Purple Urkle genetics, which carry pigments that show strongly in the buds and leaves. Cooler night temperatures in late flowering bring out the richest hues, but the color is largely genetic, so it will show to some degree even in a warmer grow. It is a big part of the strain’s fame.
How long does Granddaddy Purple take to flower?
Once you flip it to a 12/12 light cycle, Granddaddy Purple flowers for about 8 to 10 weeks before it is ready to harvest. Outdoors, it finishes around October. Because it is a photoperiod plant, you control the vegetative stage, so you can grow it to the size you want before switching the lights to begin flowering.
What does Granddaddy Purple taste like?
It has a sweet berry and grape flavor over a rich, fruity base, the classic profile it gets from Purple Urkle. Linalool brings a soft, floral note and camphene a cool, woody edge, while the berry and grape sweetness comes through from its genetics. A proper three to four week cure brings that berry-fruity character forward on the inhale, smooth and full-bodied.
Is Granddaddy Purple indica or sativa?
Granddaddy Purple is indica-dominant, at a 70/30 split, so it grows as a compact, sturdy plant with dense, often deep-purple buds, staying manageable at around 1.5 m and finishing in about 8 to 10 weeks of flowering. That balance shows in its happy, relaxed, talkative effect, which pairs an upbeat head with a comfortable, settled body.
