Chem's Sister
Also known as: Chem Sis, Chemdawg A, Chem Dog A, Chem Sister
Breeder: Chemdog (Greg Krzanowski)
Chem's Sister is one of three original female phenotypes selected by Chemdog from the legendary 13 Dog Bud seeds in 1991. Labeled 'Chemdawg A' at the time, she was the sativa-leaning outlier of the trio — more uplifting and cerebral than the sedating Chem 91 or the resin-forward Chem D. A clone-only cultivar since the mid-1990s, Chem's Sister is historically significant as the maternal parent of Gorilla Glue #4, one of the most awarded and commercially successful strains ever created. Chem's Sister occupies a foundational position in modern cannabis genetics. Originally designated "Chemdog A," it was one of three female phenotypes selected by Greg Krzanowski from the first four seeds he germinated in 1991 out of the now-mythic 13 Dog Bud seeds. While its sibling Chem 91 became the more famous keeper and the reputed ancestor of Sour Diesel and OG Kush, Chem's Sister carved its own legacy through its distinctive sativa-leaning expression — brighter, more cerebral, and less sedating than the original Chemdog. The cut first circulated widely in the mid-1990s and gained broader recognition when High Times included it in their 25 Greatest Strains of All Time list. Its most consequential genetic contribution came around 2009-2011, when breeder Joesy Whales accidentally pollinated a Chem's Sister female, eventually producing the Gorilla Glue #4 (GG4) phenotype — one of the most decorated and commercially successful strains of the 2010s. THC content typically ranges from 18-28%, with dominant terpenes of myrcene, caryophyllene, and limonene driving its signature diesel-citrus-skunk aromatic profile.
Lineage & Genetics
Cross: Dog Bud
Dog Bud — the source material for all Chemdog phenotypes. Purchased by Greg Krzanowski from P-Bud and Joe Brand at the Deer Creek, Indiana Grateful Dead show on June 6, 1991. Described as intensely potent with a 'chemmy' diesel taste unlike anything available at the time. Dog Bud's own lineage is unknown; Joe Brand traced it only to 'some friends of a friend in Crested Butte, Colorado.'
Lineage Dispute
Chem's Sister is the 'A' phenotype selected from the original 13 seeds found in Dog Bud purchased at a 1991 Grateful Dead concert in Deer Creek, Indiana. The upstream parentage of Dog Bud is completely unknown. SeedFinder classifies Chem Sister as indica, contradicting the near-universal sativa-dominant consensus from Leafly, Weedmaps, ILGM, GrowDiaries, DNA Genetics, and Greenpoint Seeds.
Terpene Profile
Myrcene —
Caryophyllene —
Limonene —
Linalool —
Humulene —
Aroma: Overwhelmingly diesel and fuel-forward — the defining Chemdawg signature amplified. Sharp ammonia and chemical notes hit first, followed by skunky funk, earthy soil, and a sweet citrus-sandalwood undercurrent. Breaking the buds open intensifies the gas-station profile dramatically. Carbon filters are essential indoors.
Flavor: Pungent diesel and chemical on the inhale with earthy, skunky undertones. The exhale softens into sweet-sour citrus, pine, and a spicy herbal finish. Less musky than Chem 91, with a cleaner citrus edge that distinguishes the A phenotype from its siblings.
Effects & Experience
Onset: Fast-acting and cerebral — within minutes of the first few hits, a sharp rush of euphoria enters the headspace.
Strongly cerebral and functional. Creativity, focus, and social energy dominate, with a gentle physical uplift that keeps the body light and mobile without sedation. Unlike Chemdawg proper, Chem's Sister does not pull toward couch-lock. Higher doses may introduce mild anxiety or paranoia in sensitive users.
Duration: 2–4 hours depending on dose and tolerance. The cerebral peak holds for roughly 60–90 minutes before gradually softening into calm alertness.
Commonly Reported Uses
Grower's Notes
Chem's Sister (also called Chem Sis or Chemdog A) is a clone-only, sativa-dominant phenotype selected from the original Chemdog seed stock by Greg Krzanowski in 1991. It was one of three females that emerged from the first four seeds germinated out of the legendary 13 found in a bag of "Dog Bud" purchased at a Grateful Dead concert at Deer Creek Amphitheatre in Noblesville, Indiana. The cut has been maintained exclusively through clonal propagation since the mid-1990s; no authentic seed lines exist commercially.
Breeder Notes
Acquiring verified genetics is the first and most critical step. Because Chem's Sister is clone-only, sourcing a legitimate cut from a reputable nursery or trusted cultivator network is essential. Mislabeled clones are common, and without the true genetics, the signature diesel-citrus resin profile will be absent regardless of how well the garden is dialed in.
Environment and Climate
This cultivar demands attentive environmental management. It thrives in warm, Mediterranean-style conditions with daytime temperatures of 70-85°F (21-29°C) and a moderate nighttime drop of 4-6°F. Relative humidity should be held at 60-65% during vegetative growth and brought down to 40-50% once flowering begins. The dense, resinous bud structure makes Chem's Sister highly susceptible to botrytis and powdery mildew, so strong, even airflow is non-negotiable. Invest in quality oscillating fans and an extraction system with carbon filtration — the latter is also essential for odor control, as this plant produces an overwhelmingly pungent diesel-skunk aroma that intensifies dramatically through flower.
Growth Structure and Training
Indoor cultivation is generally preferred for the level of control it affords. Both soil and hydroponic media work well; soil tends to produce a richer, more complex terpene expression, while hydro can push faster vegetative growth and slightly higher yields. In soil, maintain pH at 6.3-6.8; in hydro or coco, target 5.8-6.2. Feed a balanced nutrient regimen with moderate nitrogen through veg, then ramp phosphorus and potassium from week three of flower onward. Watch calcium and magnesium closely, especially under high-intensity LEDs — resin-heavy Chem lines are prone to interveinal chlorosis and tip burn when Cal-Mag is neglected.
Growth Structure and Training
Expect a significant vertical stretch of 1.5-2x during the first three weeks after flipping to 12/12. Topping, low-stress training, and SCROG are all strongly recommended to manage canopy height, improve light penetration, and maximize yield potential. Set trellis supports early, as the heavy colas can bend or snap branches in late flower. Target PPFD of 600-900 umol/m2/s during mid-to-late flowering.
Flowering Time and Harvest
Flowering runs 9-12 weeks indoors, with many growers finding peak expression around days 63-68 post flip. Trichome monitoring is critical for harvest timing: a window of mostly cloudy heads with 5-15% amber preserves the bright, cerebral character and terpene brightness that define this cut. Pushing further into amber shifts the effect toward sedation with diminishing flavor returns. Indoor yields average 12-16 oz/m2 (350-450 g/m2), with SCROG setups capable of pushing toward the high end. Outdoors in suitable climates, harvest falls between mid-October and early November, producing 16+ ounces per plant.
Pest and Disease Resistance
Pest vigilance is important throughout the cycle. Spider mites, aphids, and whiteflies are the primary threats. Organic IPM with neem oil, insecticidal soap, or beneficial predator insects is effective. Avoid overcrowding plants to promote airflow and reduce pest pressure.
History & Origin
In June 1991, Greg Krzanowski attended a Grateful Dead concert at Deer Creek Amphitheater in Indiana. He met P-Bud and Joe Brand selling 'Dog Bud' on Shakedown Street and purchased an ounce for $500. He later found 13 seeds in a mail-ordered ounce. He germinated four — one male was discarded, and the three females became Chem 91, Chem's Sister (Chem A), and Chem B. Chem's Sister circulated through tight-knit breeder networks. Her greatest historical impact came circa 2009 when a Chem's Sister plant in Joesy Whales' garden hermied and pollinated nearby Sour Dubb plants. Those seeds eventually produced Gorilla Glue #4, one of the most awarded strains in cannabis history.
Awards & Recognition
- ●3rd Place, Best Medical Hybrid — High Times Cannabis Cup (2016)
- ●Named to High Times "25 Greatest Strains of All Time" list
- ●Parent strain of Gorilla Glue #4 (GG4), which won: 1st Place Michigan Cannabis Cup (2014), 1st Place LA Cannabis Cup (2014), 1st Place Jamaica World Cup (2014), 1st Place Hempcon Cup Best Hybrid (2015), 1st Place World Cannabis Cup (2015)
Notable Crosses
Strains bred using Chem's Sister as a parent:
Frequently Asked Questions
6 common questions about Chem's Sister
What is Chem's Sister and what are its genetics?
Chem's Sister is a hybrid cannabis strain (75% Sativa / 25% Indica) bred by Chemdog (Greg Krzanowski). It is a cross of Dog Bud, testing at 18–27% THC. Chem's Sister is one of three original female phenotypes selected by Chemdog from the legendary 13 Dog Bud seeds in 1991. Labeled 'Chemdawg A' at the time, she was the sativa-leaning outlier of the trio — more uplifting and cerebral than the sedating Chem 91 or the resin-forward Chem D.
What does Chem's Sister smell and taste like?
Chem's Sister's dominant terpenes are Myrcene, Caryophyllene, Limonene. The aroma is described as overwhelmingly diesel and fuel-forward — the defining chemdawg signature amplified. sharp ammonia and chemical notes hit first, followed by skunky funk, earthy soil, and a sweet citrus-sandalwood undercurrent. breaking the buds open intensifies the gas-station profile dramatically. carbon filters are essential indoors.. The flavor profile features pungent diesel and chemical on the inhale with earthy, skunky undertones. the exhale softens into sweet-sour citrus, pine, and a spicy herbal finish. less musky than chem 91, with a cleaner citrus edge that distinguishes the a phenotype from its siblings..
What are the effects of Chem's Sister?
Fast-acting and cerebral — within minutes of the first few hits, a sharp rush of euphoria enters the headspace. Strongly cerebral and functional. Creativity, focus, and social energy dominate, with a gentle physical uplift that keeps the body light and mobile without sedation. Duration is typically 2–4 hours depending on dose and tolerance. the cerebral peak holds for roughly 60–90 minutes before gradually softening into calm alertness.. Commonly reported uses include Depression, Stress, Fatigue, Appetite loss.
How hard is Chem's Sister to grow?
Chem's Sister is rated moderate-hard difficulty. It flowers in 9-12 weeks, reaches medium-tall (60-80 in. indoor) in height, and yields 350-450 g/m² indoors. Best suited for indoor preferred environments.
What strains were bred from Chem's Sister?
Chem's Sister has been used as a parent in several notable crosses, including Gorilla Glue #4 / GG4 / Original Glue, Sister Glue / GG1, Fish Whistle, Tres Dawg, Bubba's Sis. Its genetics contribute to a wide range of modern cultivars.
Has Chem's Sister won any cannabis awards?
Yes. Chem's Sister has received recognition including 3rd Place, Best Medical Hybrid — High Times Cannabis Cup (2016); Named to High Times "25 Greatest Strains of All Time" list; Parent strain of Gorilla Glue #4 (GG4), which won: 1st Place Michigan Cannabis Cup (2014), 1st Place LA Cannabis Cup (2014), 1st Place Jamaica World Cup (2014), 1st Place Hempcon Cup Best Hybrid (2015), 1st Place World Cannabis Cup (2015).
Sources & References (37)
- SeedFinder.eu — Clone Only Strains entry
- Leafly (Canada) — Chem Sis strain page
- Weedmaps — 'Chemdog and 7 Strains That Come From It' (2021)
- MarijuanaBreak — Chem's Sister Strain Review
- DNA Genetics — Chem's Sister Terpene Profile
- I Love Growing Marijuana — Chem's Sister Review
- GrowDiaries — Chem Sis strain information
- Greenpoint Seeds — Fish Whistle (Chem Sis x Stardawg)
- Leaf Nation — 'Cannthropology: Chemdog'
- Maikoh Holistics — 'The Grateful Dead and Chemdog's Origin'
- THC Farmer — Chemdog history thread
- 3CHI — THCA Flower History of GG4
- Grower's Notes cultivation sources:
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- https://docmj.com/strain-feature-all-about-gorilla-glue-marijuana-4-gg4/
- https://www.cannaconnection.com/strains/gg4
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