Amnesia G13 by Marshall Seeds: A Comprehensive Strain Guide

Origins and Breeding History

Amnesia G13 sits at the intersection of two powerhouse families: the Haze-forward Amnesia line and the potency-famous G13 heritage. Marshall Seeds is credited with developing this cultivar, selecting for a mostly sativa expression while integrating the resin density and reliability associated with G13. The result is a modern hybrid designed to deliver classic, euphoric daytime energy with updated vigor and yield traits.

The Amnesia family rose to prominence in the Dutch scene during the 1990s and 2000s, featuring Haze-dominant chemotypes known for citrus-incense aromas and a bright, cerebral high. G13, by contrast, has long been mythologized as a high-THC indica-leaning line, treasured for its dense trichome coverage and consistent production. Marshall Seeds appears to have used that G13 backbone to temper Amnesia’s lankiness and lengthen resin windows without diluting the uplifting profile.

Because breeder releases often include multiple phenotypes, it is common to find slight variations of Amnesia G13 across seed runs or clone selections. Some cuts lean more toward terpinolene-limonene aromatics and a soaring buzz, while others carry a touch more myrcene-caryophyllene depth and physical ease. Across these phenotypes, the consistent thread is a sativa-first experience anchored by measurable potency and a refined, modern growth habit.

Genetic Lineage and Phenotypic Expectations

While the precise parental clones are proprietary to Marshall Seeds, the lineage plainly merges an Amnesia-type Haze mother line with G13 genetics. This structure predicts a mostly sativa chemotype with a terpene stack led by terpinolene and limonene, supported by myrcene, ocimene, and beta-caryophyllene. The G13 influence typically contributes increased resin production, tighter calyx stacking, and improved uniformity.

In practical terms, cultivators can expect medium-tall plants with significant stretch during the first 2–3 weeks of flowering. Many growers report 1.8–2.3x stretch following the flip to 12/12, making canopy control essential. Internodal spacing is moderate, offering enough air penetration to mitigate mold compared to denser indica-leaners.

Chemically, a significant number of sativa-dominant Amnesia crosses test with THC in the 18–24% range by dry weight under optimized conditions, and Amnesia G13 tends to align with this bracket. CBD is typically low, often under 0.5–1.0%, with minor cannabinoids like CBG frequently landing between 0.2–1.0%. Terpene totals of 1.5–3.0% by weight are common in well-grown, slow-cured samples, with top terpenes each contributing in the 0.3–0.9% range depending on phenotype and cultivation.

Appearance and Bud Structure

Amnesia G13 often displays long, tapered colas with a spear-like silhouette, a hallmark of Haze-dominant sativa structures. Buds tend to be medium density rather than rock-hard, balancing airflow with respectable calyx mass. Under strong light and consistent feed, trichome frost is conspicuous and sticky, contributing to a glossy, sugar-coated look.

Coloration typically ranges from lime and spring green to slightly darker olive tones, with copper-to-amber pistils threading through the tips. The calyx-to-leaf ratio is generally favorable, which makes trim time efficient and preserves bag appeal. In some phenotypes, subtle foxtailing appears late in flower, often as a response to high PPFD or late-stage heat, but it rarely detracts from overall bud quality.

On close inspection, resin heads are plentiful and bulbous, with a high proportion of intact capitate-stalked trichomes when properly handled. This trait makes the cultivar an attractive candidate for solventless processing, where yields benefit from dense glandular coverage. Growers commonly report that careful drying and a 4–8 week cure amplify the crystal-forward aesthetic and enhance depth of color.

Aroma Profile

The dominant bouquet is a bright, zesty citrus layered over incense-like spice, consistent with terpinolene-limonene-led Amnesia lines. Freshly ground flowers can release notes of lemon zest, sweet orange oil, and lemon balm, followed by hints of cedar, anise, and light herbal spice. Some expressions showcase tropical nuances reminiscent of mango rind and green apple skin.

On the back end, the G13 heritage can contribute a subtle earthy undertone that grounds the high-tone citrus. This earth-meets-incense character is often detectable in the jar after a proper 10–14 day dry and multi-week cure. When the terpenes are preserved, the aroma projects strongly; it is not uncommon for cured jars to perfume a room within seconds of opening.

Across phenotypes, intensity tends to sit in the medium-high range, with terpene totals frequently landing between 1.5–3.0% by weight in dialed-in grows. Limonene-driven cuts skew lemon-candy and citronella, while terpinolene-tilted phenos read as piney-citrus-incense. If myrcene shows higher, expect a softer, musky undertone amid the citrus brightness.

Flavor and Consumption Experience

Inhalation typically mirrors the nose with bright lemon-lime atop a gently resinous pine and incense base. The first draw often tastes clean and zesty, like lemon peel and sweet orange, with faint floral edges. On exhale, a cedar-spice finish lingers, sometimes with a light herbal bitterness that keeps the sweetness from cloying.

Vaporizing between 180–195°C (356–383°F) tends to showcase terpinolene and limonene without cooking off delicate top notes. At the lower end, expect a sharper citrus; at the higher end, more incense and spice will emerge alongside a fuller body feel. Combustion produces a denser, more resinous smoke with bolder cedar and pepper tones.

For edibles made with decarboxylated flower, activating at 105–115°C (221–239°F) for 40–60 minutes preserves more aromatics while fully converting THCa to THC (theoretical conversion factor ~0.877 from THCa to THC). Infusions carry a lightly citrus-herbal flavor that pairs well with chocolate, ginger, or citrus zests. Because the flavor is high-tone, a proper cure of 4–8 weeks significantly improves smoothness and perceived sweetness.

Cannabinoid Profile and Potency Data

Amnesia G13 is best characterized as a THC-forward cultivar with modest minors and typically minimal CBD. In contemporary indoor production with optimized lighting and nutrition, dried flower commonly measures THC in the 18–24% range. Select cuts, CO2-enriched grows, or dialed phenotypes can occasionally exceed 24% total THC, though such results depend heavily on cultivation and post-harvest handling.

CBD content is usually trace, frequently below 0.5–1.0%, which classifies the chemotype as Type I (THC-dominant). Minor cannabinoids often include CBG at 0.2–1.0% and THCV in trace-to-low amounts (approximately 0.2–0.7% when present). Because cannabinoid expression is polygenic and environment-responsive, actual numbers vary batch to batch.

For extraction, this cultivar’s gland density can produce efficient returns, particularly with hydrocarbon or solventless methods. In live resin or rosin formats, total cannabinoids often land in the 65–80% range with terpene totals of 5–12% for concentrates, depending on input quality. Accurate decarboxylation math during formulation uses THC ≈ THCa × 0.877, allowing more precise potency predictions in infused products.

Terpene Profile and Aromatic Chemistry

The terpene stack in Amnesia G13 commonly centers on terpinolene and limonene, with myrcene, beta-caryophyllene, beta-pinene, and ocimene as secondary contributors. In well-grown samples, total terpene content of 1.5–3.0% by weight is a realistic target, with the leading terpene often measuring 0.4–0.9%. Terpinolene brings the hallmark citrus-pine-incense blend, while limonene sharpens lemon-orange brightness and perceived mood elevation.

Myrcene can add a soft, musky undercurrent and may modulate perceived body relaxation, particularly in evening use. Beta-caryophyllene, a dietary cannabinoid that binds to CB2 receptors, contributes peppery spice and may influence perceived anti-inflammatory effects. Beta-pinene and ocimene provide green, herbal lift and light floral-tropical accents that keep the profile crisp rather than heavy.

When dialing vaporization temperatures, remember that terpenes volatilize across ranges rather than single points. A band of 175–195°C (347–383°F) typically captures the citrus-incense top-notes and mid-spice base without excessive harshness. For combustion, maintaining proper moisture (10–12% final) reduces terpene burn-off and improves flavor consistency across sessions.

Experiential Effects and User Reports

Amnesia G13’s effects present swiftly with inhalation, often within 2–5 minutes, with a clear peak around the 30–45 minute mark. Users commonly describe an uplifted, energetic onset that feels mentally spacious and creatively engaging. The high often remains head-forward for 60–90 minutes before gradually transitioning into a calmer, lightly euphoric baseline.

This cultivar is generally positioned as a daytime or early-evening strain, favored for tasks that benefit from focus, ideation, or social ease. At moderate doses, many report improved motivation, talkativeness, and a brighter outlook. At higher doses, the sativa charge can feel racy for sensitive individuals, occasionally provoking transient anxiety or heart rate awareness.

Duration for inhaled use usually runs 2–3 hours from onset, with a longer tail at larger doses. For edibles made from Amnesia G13, onset commonly arrives at 45–120 minutes with an overall window of 4–8 hours. Beginners should start low (2.5–5 mg THC) and increase gradually, as the energetic character can feel intense when overshot.

Potential Medical Uses and Considerations

The bright, THC-forward profile of Amnesia G13 suggests potential utility for mood elevation in low-to-moderate doses. Individuals report temporary relief from stress, low motivation, and situational anxiety when dosing conservatively. The limonene-terpinolene stack often correlates with subjective improvements in outlook and engagement during daytime activities.

Some patients indicate benefits for neuropathic pain and migraine-related discomfort, where THC and beta-caryophyllene may contribute to perceived relief. Users with ADHD-like symptoms sometimes find short-term focus improvements, especially when combining cannabis with structured breaks and hydration. In appetite and nausea contexts, the results are mixed; while THC can stimulate appetite, the sativa edge may reduce hunger in a subset of users.

Important cautions apply. High-THC, sativa-leaning strains can transiently exacerbate anxiety, tachycardia, or insomnia in sensitive populations. Those with a history of psychosis, severe cardiovascular disease, or pregnancy should avoid THC-dominant products unless directed by a qualified clinician.

Comprehensive Cultivation Guide

Growth habit and vigor: Amnesia G13 is mostly sativa in heritage and will stretch 1.8–2.3x after the flip. Plan for early training and canopy control to keep tops at a uniform height. Internodal spacing is moderate, and lateral branching is robust when topped and low-stress-trained.

Environment: In veg, target 24–28°C (75–82°F) during lights-on and 20–22°C (68–72°F) at night. In flower, hold 23–26°C (73–79°F) day and 19–21°C (66–70°F) night to protect terpenes. Relative humidity should be 60–70% in veg and 45–55% in flower, with a VPD of ~0.9–1.2 kPa (veg) and 1.2–1.5 kPa (flower).

Lighting: Provide PPFD of 300–600 µmol/m²/s in veg and 700–1,000 µmol/m²/s in flower, adjusting by cultivar response and CO2 availability. Daily Light Integral (DLI) targets of 35–45 mol/m²/day in veg and 45–55 mol/m²/day in flower are productive without excessive stress. Under enriched CO2 (1,000–1,200 ppm), many growers observe 15–30% yield improvements with proper irrigation and nutrition.

Nutrition and pH: In coco or hydro, maintain pH 5.8–6.2; in living soil, 6.2–6.8 is typical. Feed EC around 1.2–1.6 mS/cm in late veg, 1.6–1.8 mS/cm early flower, and 1.8–2.0 mS/cm mid-to-late flower, tapering the final week. Provide robust nitrogen in veg, then push phosphorus and potassium from week 3–7 of bloom while supplying calcium, magnesium, and sulfur steadily.

Irrigation and runoff: Water to 10–20% runoff in inert media to prevent salt buildup, adjusting frequency to pot size and root mass. As a guideline, well-rooted 3–5 gallon containers may require daily or near-daily irrigation at peak transpiration. Avoid large wet-dry swings late in flower to reduce terpene loss and prevent microcracking of trichome heads.

Training: Top once or twice in veg to build a broad, even canopy. Low-stress training (LST) and a SCROG net help manage the expected 2x stretch; flip to flower when the net is 60–70% filled. Strategic defoliation at day 21 and day 42 of flower can increase light penetration and airflow, but avoid over-stripping sativa-dominant plants.

Flowering time and yield: Expect 9–11 weeks of flowering depending on phenotype and environment. Indoor yields commonly range from 450–600 g/m² under efficient LEDs, with expert runs surpassing 600 g/m² when CO2 and irrigation are dialed. Outdoors in warm, dry climates, 600–900 g per plant is feasible with large root zones and season-long training.

Pest and disease management: The open sativa structure reduces botrytis risk compared to denser indicas but watch for powdery mildew in cool, damp conditions. Maintain at least 0.5–1.0 m/s of canopy airspeed and 20–30 room air exchanges per hour in sealed environments. Integrate beneficial insects against mites and thrips, and avoid oil-based sprays past week 2 of flower to protect resin and flavor.

Harvest readiness: Use trichome color as a primary signal—harvest at mostly cloudy with 5–10% amber for a lively, euphoric profile. Later harvests (15–20% amber) increase body depth but can dull the energetic top-end. If terpene-forward flavor is the priority, harvest during the dark cycle or early lights-on to minimize volatilization.

Drying and curing: Hang whole plants or large branches for 10–14 days at 15–18°C (59–64°F) and 58–62% RH, with gentle air exchange but no direct airflow on flowers. Target a final moisture content of 10–12% before trimming. Cure in airtight containers at 60–62% RH for 4–8 weeks, burping as needed in the first 10–14 days; this stabilizes aroma and smooths the citrus-incense finish.

Medium-specific notes: In coco (70/30 coco/perlite), keep irrigation frequent with consistent EC and avoid drybacks beyond 30% during peak flower. In organic living soil, amend with slow-release inputs and top-dress phosphorus and potassium around week 3; maintain soil moisture uniformity to support microbial activity. Hydroponic systems can deliver rapid growth but require tight control of reservoir temperature (18–20°C / 64–68°F) and dissolved oxygen.

Cloning and propagation: Cut 10–15 cm (4–6 inch) tips with two nodes, strip lower leaves, and keep domed at 22–26°C (72–79°F) with 70–80% RH. Roots generally appear in 7–14 days with moderate light (PPFD 100–200 µmol/m²/s). Seed germination typically occurs in 24–72 hours under warm, moist conditions, with fresh seed lots showing 90%+ viability when stored properly.

Outdoor guidance: In the Northern Hemisphere, plan for an October harvest; select sites with full sun and low late-season humidity. Train early to spread the canopy and stake against wind, as tall phenotypes can reach 1.8–2.5 meters with robust feeding. Preventive sulfur (pre-flower) and biologicals in veg strengthen resistance before flowers set.

Post-harvest quality control: Use a hygrometer in cure containers and keep water activity around 0.60–0.65 to inhibit mold while preserving terpenes. Avoid rapid drying, which can cost a noticeable fraction of aromatic content and increase harshness. Properly cured Amnesia G13 often shows terpene persistence for months, with citrus-incense notes holding strong when stored cool, dark, a