Grandaddy Purple Feminized Marijuana Seeds

Where Granddaddy Purple comes from

Granddaddy Purple was introduced in California in the early 2000s and quickly became one of the most famous indicas on the West Coast. It crosses Purple Urkle, a Mendocino purple phenotype prized for its grape aroma and colour, with Big Bud, an Afghan and Skunk based heavyweight known for its large colas and yield. The result kept the grape and the purple while adding size and weight to the buds.

It has been a staple of dispensary menus in the United States and Canada ever since, and it is a parent or grandparent of many newer strains, including Cherry Pie, Grape Pie and Black Mamba. The name is often spelled Grandaddy Purple, Grand Daddy Purp or simply GDP; they all refer to the same plant. Earlier listings on our own site gave a lower THC figure, but modern lab results for well grown GDP generally land between 17% and 25%.

Granddaddy Purple strain effects and experience

Granddaddy Purple is a classic nighttime indica. The first part of the effect is a soft, contented lift with a light, dreamy head. Worries fade, and most people feel calm and quietly happy rather than energetic.

Within half an hour the body side takes over. A warm heaviness spreads through the muscles, the eyelids get heavy, and many people find it hard to stay up long after a full session. Appetite also tends to wake up. With THC up to 25%, a little goes a long way. GDP is best kept for the end of the day, when you have nowhere else to be.

Granddaddy Purple flavour, aroma and appearance

The aroma is sweet and fruity: concord grape, mixed berries and a touch of sweet citrus, backed by earthy, woody notes and a hint of pine. Breaking a bud releases a deeper skunky sweetness from the Big Bud side. The smoke is smooth, with grape candy and berry on the inhale and earth, wood and a light spice on the exhale. Myrcene usually leads the terpene profile, with caryophyllene and pinene in support, which suits its relaxing, earthy character.

The buds are large, dense and rounded, often deep violet to near black with bright orange pistils and a heavy coat of white trichomes. Colour varies with temperature; a warm grow room can leave some plants mostly green, while cool nights in late bloom push almost every plant to purple.

Growing Granddaddy Purple in Canada

Indoors

GDP is a sturdy, medium sized plant with a stretch of about 1.3 to 1.5 times. Veg for four weeks and flip at 40 to 50 cm for a finished height of 80 to 120 cm. It prefers 21 to 26 degrees during the day and a drop to 15 to 17 degrees at night in the last two weeks if you want strong purple colour. It is a moderate feeder; give it extra phosphorus and potassium in bloom but go easy on nitrogen after week three. Because the buds are thick, keep humidity near 45% from week five. Harvest usually falls between day 55 and day 65.

Outdoors, by region

An 8 to 9 week bloom lets Granddaddy Purple finish outdoors across most of southern Canada. On the BC coast, plant out in late May and expect a harvest in the last days of September or the first week of October, with a rain cover ready for the dense colas. In the Okanagan and the Kootenays, dry autumn weather and cool nights make for excellent colour. In southern Ontario and Quebec, a sunny, open garden brings it in during the first week of October. On the Prairies, start seeds indoors in April, transplant after the last frost, and keep frost cloth or a garage nearby for cold nights in late September. Our outdoor cultivation guide covers soil and timing in more detail.

Height and training

Top once at the fourth node and spread the branches with low stress training. GDP has strong side branches that can support heavy buds, and a flat canopy gives six to ten large colas instead of one dominant top. Remove the lowest growth before the flip, and use a net or stakes in the last three weeks because the colas get heavy.

Flowering and harvest cues

Do not judge ripeness by colour, since the purple can appear well before the plant is ready. Check trichomes from day 55; mostly cloudy with 15% to 20% amber gives the classic heavy GDP effect. Dry slowly for 10 to 14 days at about 60% humidity, then cure for at least two to three weeks. The grape aroma grows stronger and sweeter with a longer cure.

Granddaddy Purple yield indoors and outdoors

Indoors, a trained canopy produces 400 to 500 g/m², helped by the Big Bud genetics. Outdoors, a full season plant can return 500 to 600 g, with larger plants in good soil producing more. The buds are dense and heavy, so the dried weight is reliable, and the resin makes good hash and rosin.

Who Granddaddy Purple is for, and who should pick something else

Grow Granddaddy Purple if you want a classic purple indica with grape flavour, need a relaxing strain for evenings, or want a proven parent for your own crosses. Granddaddy Purple feminized seeds are also a good choice for growers who enjoy watching a plant change colour in the fall.

Pick something else if you want an energetic daytime strain, need maximum THC, or cannot manage humidity in a wet autumn.

How Granddaddy Purple compares

Purple Urkle, the mother, is lighter, smaller and even more grape forward. Big Bud, the father, brings the size and yield. Black Mamba crosses GDP with Black Domina for darker buds and more hash. Grape Pie is a grandchild through Cherry Pie, with a pastry note on top of the grape. Among our indica feminized seeds, Granddaddy Purple remains the purple classic many growers start with.

Frequently asked questions about Granddaddy Purple

Is Granddaddy Purple indica or sativa?

Granddaddy Purple is an indica dominant strain, usually rated about 75% indica and 25% sativa. It gives a calm, happy start and then a heavy, sleepy body relaxation. The plant is medium height with large, dense buds.

What two strains make Granddaddy Purple?

Granddaddy Purple is a cross of Purple Urkle and Big Bud. Purple Urkle adds the grape flavour and purple colour, and Big Bud adds the large colas and heavy yield. It was first released in California in the early 2000s.

How strong is Granddaddy Purple?

Granddaddy Purple usually tests between 17% and 25% THC, with CBD under 1%. It is strong enough to feel very relaxing and sleepy at higher doses. Most people find a small amount is enough for an evening.

How long does Granddaddy Purple take to flower?

Granddaddy Purple flowers in about 8 to 9 weeks, or 55 to 65 days after switching to 12 hours of light. In a Canadian garden, expect to cut it from the last week of September into early October. Cool nights near the end of bloom bring out its purple colour.