Is Granddaddy Purple indica or sativa? Its genetics and family tree

The parents in each account

Purple Urkle is a California indica whose origins, Leafly says, are believed to stem from a select phenotype of Mendocino Purps. Big Bud is an indica that Leafly describes as a three-way cross of Afghani, Northern Lights and Skunk #1, first developed in the United States and taken to the Netherlands in the 1980s.^13,14

Leafly’s own account uses older names. Mendocino Purps, or Mendo Purps, comes from Mendocino County in Northern California, began as a clone-only plant and took a top-ten slot in High Times’ Strains of the Year in 2007; Leafly lists Granddaddy Purple and Grape Ape as its children.¹⁵ Skunk #1 was bred by Sacred Seed Co. in the late 1970s from Afghani, Acapulco Gold and Colombian Gold, and Afghani, which Leafly also lists under the name Afghanistan, is an indica named for its geographic origin that breeders prize for its heavy resin.^16,17

What Ken Estes says

In a 2026 interview with Leafly, Estes said a man whose house he had helped save showed him a plant called Purple Medicine, which was not grown commercially because it yielded only about a pound per light; he drove up to Humboldt to see it, named it after his first thought on picking up the first pound, “this is like the grandpa of all weed”, and launched it in Oakland in 2003. He does not name parent strains in that interview.⁶

Leafly’s history of the Purps family cites an earlier Estes interview with Klub Kush Magazine in which he said his cut came from crossing Skunk strains to express purple traits, and its timeline describes “Ken’s GDP” as using Skunk instead of Afghani and Kush. The same article reports that Dark Heart Nursery acquired a GDP cutting attributed to Estes in 2003, and quotes Ghost of ABF Genetics: “Nobody in the Bay ever called it that.”¹⁹

How indica is it?

Every source leans indica, but the labels vary by version: Leafly and Weedmaps call it an indica, AllBud an indica-dominant hybrid at 70% indica and 30% sativa, Royal Queen Seeds 75% indica for its feminized seeds and United Cannabis Seeds 80% for its own, while SeedFinder’s description of Apothecary’s plant calls it “all-indica”.^1,2,3,4,5,18 Royal Queen Seeds’ autoflower, a cross with Big Bud Auto, is listed at 75% indica, 20% sativa and 5% ruderalis.²⁰

Ken’s GDP, clones and seed versions

Estes’s breeder name on SeedFinder is Grand Daddy Purp, whose page introduces him by name and says his “Grand Daddy Purp” strain was developed in 2003; it lists the strain as regular seeds only, never feminized, with a genealogy that shows a backcross of Grand Daddy Purple.^21,22 Weedmaps says the strain is available as a clone from Dark Heart Nursery in Northern California.²

Seeds sold under the name are not all the same plant. SeedFinder lists nine breeders’ versions, among them Royal Queen Seeds, United Cannabis Seeds and Atlas Seed, and High Times reported that Purple Punch’s mother came from “an old pack of Granddaddy Genetics’ GDP”.^23,24 The description on SeedFinder’s “Unknown or Legendary” entry, which says Apothecary has been growing and refining the plant (the Apothecary text cited on this site), says its phenotypes have been known by names including Grape Ape, Purple Erkel and Grandaddy Grape Ape.¹⁸

Granddaddy Purple and Grape Ape

The two names are easy to mix up, and the sources mix them too. Leafly gives Grape Ape the same three parents it gives Granddaddy Purple, Mendocino Purps, Skunk and Afghani; a photo caption in Leafly’s Purps history calls a 2014 Grape Ape a “child of GDP”; and the Apothecary text lists Grape Ape among GDP’s phenotype names.^1,18,19,25 Our comparison sets them side by side: Granddaddy Purple vs Grape Ape.

What our lab data adds

Our lab matching treats the initials GDP and the common spellings (Grand Daddy, Grandaddy, Purp, Purps) as one strain, and accepts “Ken’s” in front of the name as the breeder-of-record prefix; 20 of the 512 tests carry it.²⁶

We excluded 161 results sold under near-miss names. Among the most frequent were the crosses “Harlequin x GDP” (10), “WC x GDP” (8), “gdp x animal cookies” (5), and vape and distillate products such as “Stiiizy Infused Distillate Grand Daddy Purple Bulk” (21); besides the flower tests we use, 292 concentrate results matched the name strictly.²⁶ None of this tests parentage: matching is by label text, and the same name from different growers can be different genetics.