G13 Haze
Cannabis seeds
by Mr. Nice Seedbank
G13 Haze Cannabis Seeds by Mr. Nice
G13 Haze is a regular cannabis seed variety from Mr. Nice that crosses the legendary G13 clone with a pure Haze male — two old-school genetics fused into a single, potent hybrid. Bred by Nevil and Shantibaba, this strain carries serious pedigree and delivers THC levels between 18% and 23%. It is a limited edition release, so once it is gone, it is gone.
Pack Size
Available in packs of 15 regular seeds (SKU: CSMN0018). Regular seeds produce both male and female plants — expect roughly a 50/50 split, so you will want to sex your plants early and remove males unless you are breeding.
Why G13 Haze Seeds Belong in Your Collection
There is a reason growers keep coming back to Mr. Nice genetics: Nevil Schoenmakers and Shantibaba built their reputation on working with original, verified clone-only cuts — not second-hand copies of copies. The G13 clone used here is the real deal, and crossing it with a Haze introduced that soaring sativa character that pure G13 lacks on its own. The result is a strain that leans heavy on potency and flavour while offering enough phenotypic variation to keep things interesting.
We have seen a lot of G13 crosses come through over the years, and the Mr. Nice version stands apart because of its breeding stock. If you have grown Neville's Haze or SSH from Mr. Nice before, you already know the quality of their Haze lines. G13 Haze takes that same male and pairs it with one of the most storied indica clones in cannabis history. The offspring are vigorous, resinous, and — fair warning — not the easiest plants to manage. More on that below.
According to research compiled by Healthline, indica-dominant and hybrid strains with high THC content have traditionally been associated with relaxation and appetite stimulation, though individual responses vary considerably. A WHO Expert Committee report on cannabis noted that cannabinoid concentrations in the brain and serum are influenced by the specific cannabinoid profile of the plant material consumed (WHO Expert Committee on Drug Dependence). With THC levels reaching up to 23%, G13 Haze sits firmly in the high-potency bracket.
G13 Haze Growing Specifications
| Specification | Detail |
|---|---|
| Breeder | Mr. Nice Seeds |
| Genetics | G13 clone x Haze |
| Seed Type | Regular (non-feminised) |
| Seeds per Pack | 15 |
| THC Range | 18–23% |
| Indoor Flowering Time | 9–11 weeks |
| Indoor Yield | 500–750 g/m² |
| Outdoor Harvest (Northern Hemisphere) | November – early December |
| Outdoor Harvest (Southern Hemisphere) | May – June |
| Recommended Setup | Bio or hydro |
| Difficulty | Experienced growers |
How to Grow G13 Haze Seeds
G13 Haze thrives in bio and hydro setups. The phenotypic variation between seeds is wider than you might expect — some plants lean sativa-dominant with stretchy internodes and longer flowering, while others show more of the G13 indica structure. That unpredictability is part of the appeal if you are pheno-hunting, but it does mean you need to pay attention.
- Germinate your G13 Haze seeds using your preferred method — paper towel, jiffy plugs, or direct into a starter medium. Regular seeds are robust germinators, but keep temperatures between 22–26°C for best results.
- Transplant seedlings into your bio or hydro setup once they have developed their first set of true leaves. This strain responds well to both growing methods, so use whichever system you are most comfortable with.
- Provide 18–24 hours of light during the vegetative stage. G13 Haze is a hungry plant that benefits from strong lighting — if you are running LEDs, do not skimp on wattage.
- Sex your plants early. With 15 regular seeds, you will likely get 7–8 females. Remove males as soon as pre-flowers appear unless you are deliberately breeding.
- Switch to a 12/12 light cycle to trigger flowering. Sativa-leaning phenotypes may stretch significantly during the first 2–3 weeks of flower — plan your canopy height accordingly or use training techniques like LST or a SCROG net.
- Watch your EC levels carefully. The more sativa traits a phenotype shows, the more sensitive it is to high nutrient concentrations. Experienced hydro growers report using bloom-stage nutrients at around 0.45 ml/L as a starting point, adjusting upward based on plant response.
- Harvest between weeks 9 and 11 of flowering. Sativa-dominant phenotypes will push closer to 11 weeks; indica-leaning ones may finish by week 9. Check trichomes under magnification — milky with a few amber heads is the sweet spot for most growers.
- Flush your medium during the final 1–2 weeks before harvest. This is particularly relevant in hydro setups where salt buildup can affect the flavour of your final product.
The Honest Limitations of G13 Haze
This is not a beginner strain. We would not recommend G13 Haze to anyone who has not already grown at least a couple of sativa-leaning varieties. The phenotypic spread means two plants from the same pack can behave very differently — one might finish flowering in 9 weeks at a manageable height, while the next stretches to the ceiling and needs 11 weeks. If you only have room for 2–3 plants and need predictable results, a feminised variety like Super Silver Haze or Critical Mass might be a safer bet.
The EC sensitivity is real. We have seen growers burn sativa-dominant phenotypes by running the same nutrient schedule they use for indica-heavy strains. Start lower than you think you need to and ramp up gradually. The plant will tell you when it is hungry.
On the upside, the yield potential is genuinely impressive for a haze cross. Hitting 500–750 g/m² indoors is no joke — that is commercial-grade output from a strain that also delivers on potency and flavour. The resin production on well-grown G13 Haze is thick and aromatic, with that classic haze spiciness supported by the denser, earthier notes from the G13 parent.
G13 Haze for Breeding and Poly Hybrids
G13 Haze regular seeds are a strong foundation for creating new poly hybrids. The combination of G13's tight structure and potency with the Haze's cerebral character and vigour gives you a versatile starting point. Because these are regular seeds, you get access to both male and female plants — critical if you are selecting a male for pollen production. Mr. Nice specifically notes this strain's value in breeding projects, and the genetic diversity within the pack gives you plenty of material to work with when selecting parent plants.
According to research published in PMC on sink strength and nutrient allocation in cannabis, THC-dominant chemovars showed superior sink strength and higher flower biomass compared to CBD-dominant varieties, with demand-driven control of nutrient uptake (PMC, 2024). This aligns with what growers report about G13 Haze — the high-THC phenotypes tend to be the heaviest feeders and biggest yielders in the pack.
G13 Haze Compared to Other Mr. Nice Strains
| Trait | G13 Haze | Super Silver Haze | Critical Mass |
|---|---|---|---|
| Genetics | G13 x Haze | Skunk x NL5 x Haze | Afghani x Skunk |
| Seed Type | Regular | Regular | Regular |
| Flowering Time | 9–11 weeks | 9–11 weeks | 6–8 weeks |
| Indoor Yield | 500–750 g/m² | 450–600 g/m² | 400–600 g/m² |
| THC | 18–23% | 18–22% | Moderate |
| Difficulty | Experienced | Experienced | Beginner-friendly |
| Best For | Pheno-hunting, breeding | Classic haze flavour | Fast, reliable yields |
If you want the haze character but with a bit more predictability, Super Silver Haze is the safer pick. If you just want weight and speed, Critical Mass finishes weeks earlier. G13 Haze is the one you grow when you want something special — a limited edition cross with genuine breeding potential and a THC ceiling that the others cannot quite match.
Complete your setup with a quality propagation kit to give these regular seeds the best start. A root stimulator pairs well with G13 Haze's vigorous early growth, and a SCROG net will help you manage the sativa stretch during early flowering. If you are running hydro, pick up a reliable EC meter — this strain punishes sloppy nutrient management.
What G13 Haze Smells and Tastes Like
Crack open a cured jar of well-grown G13 Haze and you get hit with that unmistakable haze spice — sharp, almost incense-like, with a sweetness lurking underneath. The G13 parent adds a denser, earthier layer that grounds the whole profile. When vaporised, the terpene profile becomes more pronounced, with notes of pine and musk coming through alongside the spice. It is not a subtle smoke. Your neighbours will know.
The flavour carries through on the exhale with a peppery, slightly floral finish that lingers. If you have ever smoked a proper old-school haze from the late '90s or early 2000s, this will feel familiar — but with more body and depth from the G13 genetics.
Frequently Asked Questions
How does G13 Haze compare with other popular haze strains?
G13 Haze delivers higher yield potential (500–750 g/m²) than most haze crosses, with THC reaching 18–23%. The G13 parent adds indica structure and resin production that pure hazes lack. The trade-off is less predictable phenotypes — you will see more variation between plants than with stabilised haze hybrids.
Is G13 Haze suitable for outdoor growing?
Yes, but only in warm climates with long autumns. In the Northern Hemisphere, harvest falls between November and early December — that is late, and frost or heavy rain can be a problem in northern Europe. Southern Hemisphere growers harvest between May and June. Indoor growing gives you far more control over this strain.
How should I store G13 Haze seeds?
Keep them in a cool, dark, dry place — a sealed container in the fridge at around 6–8°C is the gold standard. Avoid temperature fluctuations and moisture. Properly stored cannabis seeds can remain viable for several years, though germination rates may gradually decrease over time.
Why are these regular seeds instead of feminised?
Mr. Nice releases G13 Haze as regular seeds to preserve the full genetic spectrum. Regular seeds give you access to male plants for breeding and tend to produce more vigorous, genetically diverse offspring. If you want only females, you will need to sex your plants during early flowering and remove males.
What EC level should I use for G13 Haze in hydro?
Start conservative — around 0.45 ml/L of bloom nutrients is a reasonable starting point based on grower reports. Sativa-dominant phenotypes are particularly sensitive to high EC values. Increase gradually and watch for signs of nutrient burn (leaf tip yellowing). The indica-leaning phenotypes can handle slightly more.
Can G13 Haze be used for breeding new hybrids?
Absolutely — Mr. Nice specifically recommends this strain for creating poly hybrids. The combination of G13 potency and Haze vigour makes it a versatile parent. With 15 regular seeds, you have enough material to select standout males and females for your breeding programme.
What is the strongest phenotype of G13 Haze?
THC levels range from 18% to 23% across phenotypes. The sativa-dominant expressions tend to deliver the most intense cerebral effect but take longer to flower (closer to 11 weeks). Indica-leaning phenotypes finish faster and produce denser flowers but may sit at the lower end of the THC range.
Last updated: April 2026
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Medical disclaimer. This content is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare provider before use of any substance.