Jack Herer

Jack Herer Feminised Cannabis Seeds by Greenhouse Seeds

Jack Herer is a feminised cannabis seed variety from Greenhouse Seeds that crosses a Haze with Red Skunk to produce a heavy-yielding, 20% THC hybrid named after the legendary marijuana activist. This strain delivers a strong cerebral and physical effect, with indoor yields reaching 800g/m² and outdoor harvests of up to 1.2kg per plant. It's one of the most decorated strains in cannabis cup history — and for good reason.

Why Jack Herer Seeds Belong in Your Grow Room

We've been stocking Greenhouse Seeds since our early years, and Jack Herer has stayed in the catalogue for one simple reason: it performs. This isn't a trendy strain that shows up for a season and disappears. It's a proven Haze-Skunk cross that consistently delivers fat, resinous buds with a THC level that sits firmly at 20%. That's enough to put even seasoned smokers in their seat — and Greenhouse Seeds recommends you be seated when you sample it.

The numbers speak for themselves. Indoors, Jack Herer yields between 700 and 800g/m² after just 8 weeks of flowering. Outdoors, under good conditions, individual plants can produce up to 1.2kg by the end of September. Those are not wishful-thinking figures — this strain has the genetics and the track record to back them up. It responds particularly well to SOG and ScrOG methods, so if you've got the training technique down, you'll be rewarded with an absolutely packed canopy.

The one thing to watch: that Haze parentage means Jack Herer can stretch during the first weeks of flower. If you're working with limited headroom — say a 120cm tent — you'll want to flip early or keep on top of your training. It's not unmanageable, but it's not a compact indica either. Plan your vertical space accordingly.

What Jack Herer Buds Look and Smell Like

When Jack Herer is properly grown and dried, the buds look like oversized clusters of green popcorn — dense, chunky nuggets absolutely riddled with orange pistils. The trichome coverage is heavy enough that the buds look like they've been rolled in powdered sugar. Crack one open and you get that classic Haze sharpness — spicy, slightly piney, with a skunky undertone from the Red Skunk side of the family. The resin production is genuinely impressive; your fingers will be sticky after handling even a small amount.

Compared to something like White Widow (another Greenhouse Seeds classic), Jack Herer runs warmer and more complex on the nose. White Widow leans earthy and sweet; Jack Herer has more bite. If you enjoy strains with character rather than generic "dank," this one delivers.

Jack Herer Cannabis Cup Wins

This strain has collected more trophies than most seed banks have strains. Here's the documented competition history — and Greenhouse Seeds themselves admit they've probably missed a few:

That's at least 10 documented placements across 7 years, with multiple first-place finishes. You'd be hard-pressed to find another single strain with this kind of competition pedigree.

How to Grow Jack Herer Feminised Seeds

1. Germinate your Jack Herer seeds using the paper towel method or directly in a propagation plug. Keep temperatures between 22–26°C and maintain high humidity (around 70%) until taproots emerge — typically within 48–72 hours.
2. Transplant seedlings into their growing medium once the taproot is 1–2cm long. Jack Herer does well in soil, coco, or hydro. If you're running coco or hydro, keep EC levels moderate during the seedling stage — this strain doesn't need heavy feeding early on.
3. During vegetative growth, start training early if you're using SOG or ScrOG. Jack Herer's Haze genetics mean it will stretch, so topping once or twice during veg helps create a more even canopy and controls height. Aim for 3–5 weeks of veg depending on your setup and target plant count.
4. Flip to 12/12 when your canopy fills roughly 60–70% of the screen (ScrOG) or when plants reach about half your desired final height. Expect noticeable stretch during the first 2 weeks of flower.
5. Flowering takes approximately 8 weeks. During weeks 3–6, you'll see the characteristic popcorn-shaped bud clusters forming and trichome production ramping up. Maintain good airflow — the dense bud structure can trap moisture if ventilation is poor.
6. Harvest when trichomes show mostly milky with some amber. For outdoor growers, this falls around the end of September in most European climates. Indoor yields of 700–800g/m² are realistic with SOG or ScrOG; outdoor plants can produce up to 1.2kg each under optimal conditions.
7. Dry slowly in a dark room at 18–20°C and 55–60% humidity for 10–14 days, then cure in glass jars for at least 2 weeks. The Haze terpene profile develops significantly during a proper cure — rushing this step costs you flavour.

Frequently Asked Questions

Last updated: April 2026