What Is GG4 and Why Does It Challenge Growers?
GG 4 — officially renamed Original Glue by GG Strains after a legal dispute — is one of the most resin-saturated hybrids ever stabilized. Cross it out of your mind as a beginner-friendly strain: GG4 rewards growers who pay attention to canopy management, humidity control, and harvest timing. Get those three things right, and you're looking at dense, frosted colas that practically drip with trichomes. Get them wrong, and you'll fight bud rot, light burn, and a harvest that undershoots its genetic potential.
According to grow journals tracked on Grow Guide, the majority of indoor growers working with GG4 run it in soil (63% of all tracked grows platform-wide use soil), which suits this strain's moderate-to-heavy feeding style well. This guide covers every stage from veg setup through cure, with specific numbers at every step.
Setting Up Your Environment for GG4
Temperature and VPD
GG4 performs best between 74°F and 78°F (23–26°C) during lights-on. Drop temps 5–8°F during lights-off to encourage resin production and reduce stretching. For VPD, target 0.8–1.0 kPa during vegetative growth and push toward 1.2–1.5 kPa during mid-to-late flower to stress the plant productively without triggering heat stress.
Humidity — The Critical Number for GG4
This is where most GG4 grows go sideways. The strain's notoriously dense bud structure traps moisture in the interior of colas, creating perfect conditions for Botrytis cinerea (bud rot). Keep relative humidity at:
- Seedling/early veg: 60–70% RH
- Late veg: 55–60% RH
- Early flower (weeks 1–3): 50–55% RH
- Mid-to-late flower (week 4 onward): 40–45% RH
- Final two weeks: Drop to 35–40% RH
If you're seeing any discoloration deep in your colas after week 6, pull those buds apart — bud rot can wipe out 30% of your harvest before it's visible on the surface.
Airflow and Ventilation
Run at least two oscillating fans in your tent — one at canopy level, one below pointing up through the understory. Your exhaust fan should achieve a full air exchange every 1–3 minutes. For a 4×4 tent, that means a minimum 200 CFM fan. GG4's dense structure demands this; low airflow is not a negotiable shortcut with this strain.
GG4 Training: Tame the Stretch Before It Costs You
GG4 will stretch 50–100% of its vegetative height during the first three weeks of flower. A plant that enters flower at 18 inches can finish at 36 inches — or more. Plan for this. See our Fimming vs Topping guide for technique comparison, but here's the GG4-specific approach:
Topping and Low-Stress Training (LST)
Top your GG4 once at node 4–5 during veg (around day 21–28 from seed). Allow the two main shoots to develop, then top again 10–14 days later to create 4 main colas. Begin LST immediately after each topping by bending and securing lateral branches outward with soft ties or pipe cleaners. You're building a wide, flat canopy — not a Christmas tree.
SCROG for Maximum GG4 Yield
A Screen of Green (SCROG) setup is the highest-yield method for GG4 indoors. Place your net at 16–20 inches above the pot. During veg, tuck any growth that pokes above the net back through until the screen is 60–70% filled before flipping to 12/12. Once you flip, stop tucking and let colas shoot upward through the screen. With a properly filled SCROG, the 18–21 oz/m² ceiling becomes achievable rather than theoretical.
Use our Yield Calculator to estimate your harvest weight based on canopy size, light intensity, and grow medium before you even flip to flower.
GG4 Lighting: PPFD Targets by Stage
GG4 is not the most light-hungry strain, but it absolutely rewards dialing in your PPFD correctly. Use our Grow Light Calculator to match your fixture output to your canopy area. Rough targets:
- Seedling: 200–400 µmol/m²/s PPFD
- Veg: 400–600 µmol/m²/s PPFD, 18/6 photoperiod
- Early flower: 600–800 µmol/m²/s PPFD
- Peak flower (weeks 4–7): 800–1,000 µmol/m²/s PPFD
- Late flower/pre-harvest: Back down to 600–700 µmol/m²/s
Overdriving light on GG4 causes bleaching at the top colas — a common error when growers see how well the plant responds and crank intensity too high. Keep your light-to-canopy distance appropriate for your fixture's output. LED fixtures typically run best at 18–24 inches above canopy for GG4.
Nutrients and Feeding Schedule for GG4
GG4 is a moderate-to-heavy feeder, particularly during mid-flower. In soil, target these EC ranges:
- Early veg: EC 0.8–1.2, pH 6.2–6.8
- Late veg: EC 1.2–1.6, pH 6.2–6.8
- Early flower (weeks 1–3): EC 1.4–1.8
- Mid flower (weeks 4–7): EC 1.8–2.2 — ramp up P and K
- Flush (weeks 8–9): Plain water, EC below 0.5
In coco coir, run pH 5.8–6.2 throughout and expect to feed daily. EC tolerance is slightly higher in coco — you can push to EC 2.4 in peak flower without burn if you're watering to 10–15% runoff each time.
Magnesium Deficiency — GG4's Most Common Problem
If you see interveinal yellowing on mid-canopy fan leaves between weeks 3 and 6, that's almost certainly a magnesium deficiency — one of GG4's most documented issues. Supplement with CalMag at 2–5 mL/L, or use a dedicated Epsom salt solution (1 tsp/gallon). If you're unsure what you're looking at, run it through our Nutrient Deficiency Identifier before throwing product at the problem. For more on seedling-stage nutrition to set a strong foundation, see our Best Nutrients for Cannabis Seedlings guide.
Harvesting GG4: Reading Trichomes Correctly
GG4 finishes flowering in 8–9 weeks from flip. Don't trust the calendar alone — use a 60–100x loupe or digital microscope to read trichomes on sugar leaves and bud calyxes (not just fan leaves, which amber faster).
- All cloudy trichomes: Maximum potency, energetic effect — harvest window is open
- 10–20% amber: Balanced effect, peak THC with onset of CBN conversion — most growers target this
- 30–40% amber: More sedative, couch-lock profile — useful for some use cases
Flush for 7–14 days before harvest in soil (skip or shorten flush in coco). Stop all feeding and watch for leaves naturally yellowing — that's the plant consuming its own stored nutrients, which is what you want. Plan your harvest timing using the Grow Schedule Planner so your dry and cure window doesn't catch you off guard.
Drying and Curing GG4 for Maximum Terpene Expression
GG4's terpene profile — caryophyllene, myrcene, and limonene, producing notes of chocolate, coffee, and pine — is highly volatile. Rushed drying destroys it. Here's the protocol:
Drying
- Hang whole branches (or use drying racks for heavy colas) in a dark room at 60–65°F and 55–60% RH
- Target a slow dry of 10–14 days — not the common 5–7 day rush
- Run a small fan for air circulation but never point it directly at buds
- Stems should snap cleanly (not bend) before you jar up
Curing
- Trim, jar into wide-mouth glass mason jars at 58–62% RH (use Boveda or Integra Boost packs)
- Burp jars twice daily for the first two weeks: open for 10–15 minutes each time
- Weeks 3–4: burp once daily
- After week 4: burp every 2–3 days
- Minimum cure: 4 weeks. Optimal for GG4: 6–8 weeks — the chocolate and pine notes develop noticeably after the 5-week mark
Track every burp and note aroma changes using our Dry & Cure Timer. If jars smell like ammonia at any point, leave lids fully off for 2–4 hours — that's anaerobic bacteria and means your buds were too wet when you jarred.
Trimming GG4: Prepare for a Sticky Situation
GG4 earned its name honestly. Within 20 minutes of wet trimming, your scissors will be coated in a thick layer of resin that makes cutting nearly impossible. Keep a small cup of 91%+ isopropyl alcohol next to your workstation and wipe blades every 10–15 minutes. Wear nitrile gloves — they'll also accumulate resin, which you can roll into finger hash. Machine trimming is not recommended for GG4 if you care about trichome preservation; the dense resin clogs drum trimmers fast and damages the trichome heads you've worked 15 weeks to develop.
To understand the full terpene profile you're preserving through trim and cure, explore our Terpene Explorer — GG4's caryophyllene, myrcene, and limonene combination is particularly interesting to map.
Tracking Your GG4 Grow
GG4 is a strain that rewards detailed note-taking. Small adjustments to humidity in week 6, a CalMag top-up in week 4, or pulling the harvest two days later can significantly affect your final product. Keeping a structured grow journal means you can repeat what worked and avoid what didn't. See our guide on How to Keep a Cannabis Grow Diary for a practical system, or check the complete 2026 grow diary guide for a more detailed approach. You can also log your GG4 grow directly on Grow Guide to track progress and compare notes with other growers running the same genetics.
Frequently Asked Questions
How long does GG4 take to flower?
GG4 typically finishes flowering in 8–9 weeks from the flip to 12/12. Total seed-to-harvest time indoors is usually 14–17 weeks depending on how long you run veg. Add 10–14 days for drying and 4–8 weeks for curing before the final product is fully ready.
What yield can I expect from GG4 indoors?
Under optimal conditions with a SCROG setup and well-dialed environment, GG4 can yield 18–21 oz/m² (500–600 g/m²) indoors. Untrained plants in smaller setups will typically yield significantly less. Use the Yield Calculator to estimate based on your specific setup.
How do I prevent bud rot on GG4?
Keep relative humidity below 45% from week 4 of flower onward, and drop to 35–40% in the final two weeks. Run oscillating fans to ensure airflow reaches inside the canopy, and inspect the inner portions of dense colas weekly for any discoloration or soft spots.
Why is my GG4 showing yellowing between leaf veins?
Interveinal yellowing on GG4 is almost always a magnesium deficiency. Supplement with CalMag at 2–5 mL/L or Epsom salt at 1 tsp/gallon. If you're unsure of the diagnosis, use the Nutrient Deficiency Identifier before adjusting your feed program.
How long should I cure GG4 for best flavor?
A minimum of 4 weeks is needed, but GG4's signature chocolate and pine terpene notes don't fully emerge until weeks 5–6 of cure. For the best expression of the strain's profile, aim for a 6–8 week cure at 58–62% RH in sealed glass jars, burping regularly throughout.
References
- GG Strains (2024). Original Glue (GG4) — Official Strain Information. GG Strains LLC. Details the legal renaming and original genetics of GG4. ggstrains.com
- Cannabis Business Times (2023). Original Glue (GG4) from GG Strains — Cultivation Profile. Reports optimal temperature range of 74–78°F and notes on managing light intensity for GG4. cannabisbusinesstimes.com
- StrainGuide (2024). GG4 Strain: Effects, Terpenes, THC & Grow Guide. Documents magnesium deficiency prevalence, P/K feeding windows in weeks 4–7, and 4–6 week cure recommendations for GG4. strainguide.app
- Green Camp (2023). Gorilla Glue Strain Review. Covers humidity management below 45% during late flower, airflow requirements, and isopropyl alcohol use for trimming tools. greencamp.com
- Grow Guide Platform Data (2026). Internal grow journal analytics across 1,000 tracked grows. Shows 73.2% of all tracked grows are conducted indoors, with 63.3% of growers using soil as their primary medium — context for GG4 cultivation environment recommendations.
