Jack 47 F1 Fast Seeds

Feminized Seeds

Various Quantities

Price range: $32.25 through $54.00

🎃 Halloween Sale: 25% off through Sunday at midnight Pacific.
3 free Buds & Roses seeds in orders $75+, a full 6-pack at $175+. Want a certain strain? Add it to your order notes (not guaranteed).

Pack Size (Sweet Seeds)

Clear

25% Off

Jack 47 x Jack 47 Auto. Sativa Dominant. Fast-flowering feminized seeds by Sweet Seeds.

Jack 47 F1 Fast fast-flowering feminized cannabis seeds by Sweet Seeds. A quicker, photoperiod-based version of a sativa-leaning classic, offering fruity and minty flavor, high THC in the 16 to 24% range, and a very high outdoor yield ceiling. Sold in 3 and 5-seed packs.

Grow specs

Genotype	Sativa Dominant
Genetics	Jack 47 x Jack 47 Auto
Seed type	Feminized, fast-flowering photoperiod
Flowering time (indoor)	6 to 8 weeks
Indoor yield	High (450 to 600 g/m²)
Outdoor yield	Very high (above 750 g per plant)
THC	High (16 to 24%)
CBD	Medium (1 to 5%)
Plant height	Medium
Flavor	Fruity, minty

About Jack 47 F1 Fast

This is an F1 version of the original Jack 47, made by crossing a photoperiod Jack 47 with its own autoflowering version. The result keeps the 12/12 flowering requirement of the parent but finishes sooner. The genotype is sativa dominant.

Breeders describe the plant as vigorous and adaptable, and that matches its record of working across different growing methods. THC runs high, in the 16 to 24% range, with CBD between 1 and 5%. Because the seeds are feminized, you do not need to sort males from females, and that makes planning a tent or a garden bed much simpler. The earlier finish compared with the full-term Jack 47 is the reason to pick this version.

How it grows

Jack 47 F1 Fast needs a 12/12 light schedule to flower, then finishes in about 6 to 8 weeks. Plants reach a medium height with vigorous growth, so give the canopy room and train early.

Indoor yields are rated high at 450 to 600 g/m². Outdoors the rating climbs to very high, above 750 g per plant, which makes it a standout for growers with space and sun. A sativa-dominant frame responds well to topping and a light trellis, so use them early to spread the canopy.

Flavor, aroma and effect

Fruity and minty is the combination here. Expect a sweet, juicy fruit note paired with a cooler mint edge, a mix that gives the flowers a fresh character rather than a heavy one. The sativa-leaning ancestry shows in how bright the aroma reads.

Who it is for

Suits growers who like sativa-dominant plants but would rather not wait through a full-length flowering. It rewards those with outdoor space, given the very high yield rating, and works equally well in a tent where a medium plant with a faster finish keeps cycles moving.

Pack options

Jack 47 F1 Fast Seeds from Sweet Seeds come in 2 pack sizes: 3 seeds ($43) and 5 seeds ($72). Every seed is feminized. This is a photoperiod plant bred for a shorter bloom, so it still needs a 12/12 light schedule to start flowering.

Seed Germination Instructions

for cannabis seeds

Step 1: Soak the seeds

Fill a glass with clean, room-temperature water (68-77°F / 20-25°C).
Use filtered, dechlorinated, or pH-balanced water to prevent contaminants.
Drop the seeds into the water and gently swirl to ensure full submersion.
If seeds float, tap them down lightly or leave them to absorb water.
Optional: Add 3% hydrogen peroxide (H₂O₂) at a ratio of 1 ml per 100 ml of water to prevent mold and bacteria.
Place the glass in a dark, warm location for 2-6 hours (do not exceed 12 hours to prevent drowning).

Step 2: Prepare the Germination Plate

Dampen two layers of paper towel, cotton, or thick toilet paper with clean, dechlorinated water.
If using toilet paper, fold multiple plies to ensure adequate thickness.
Place seeds evenly between the layers, ensuring they do not touch each other.
Towels should be moist but not soaking wet.
Set the damp towel on a plate and cover with another plate or place it inside a resealable plastic bag to retain moisture.
Store in a dark, warm location (70-78°F / 21-26°C) such as a drawer or cabinet.
Check the moisture level every 6-12 hours and add water as needed to prevent drying.
Expected Germination Time:
- Most seeds crack open within 48-72 hours.
- Some may take 5-6 days to show taproots.
- Older seeds or seeds with a tougher shell may take up to 10-15 days to sprout.
- If a seed has not sprouted within 10 days, gently check it for signs of swelling or softening.

Step 3: Monitor Germination

Seeds typically crack open and develop a taproot within 48-72 hours, but some may take up to 5-6 days.
Older or dormant seeds may take 10-15 days to sprout, especially if they have a thicker shell.
Check regularly for signs of mold or fungal growth.
If mold appears, replace the paper towel and rinse seeds in a diluted hydrogen peroxide solution (1 ml of 3% H₂O₂ per 100 ml water).
The seed is ready for planting when the white taproot emerges and reaches ¼-½ inch (0.6-1.3 cm).

Step 4: Planting the Seeds

Prepare a pH-balanced growing medium (pH 5.5-6.0) such as:
- Quality soil-perlite mix
- Coco coir with perlite
- Rockwool cubes (must be pre-soaked in pH 5.5 water)
Plant the seed 2-5 mm deep, with the root tip facing downward.
Use containers that are at least 10 cm (4 inches) deep with drainage holes for healthy root development.
Lightly cover the seed with soil—do not press down too hard.
Spray the top layer with water instead of drenching it.

Step 5: Initial Care for Seedlings

Keep the growing medium moist but not waterlogged—spray with a spray bottle instead of overwatering.
Maintain high humidity by:
- Covering containers with clear plastic wrap or a humidity dome.
- Ensuring there is some airflow to prevent mold buildup.
Place seedlings under cold white LED or fluorescent lights or in indirect sunlight at 68-77°F (20-25°C).

Step 6: Gradual Exposure to Light

Once seedlings emerge and develop their first set of leaves (cotyledons):
- Slowly introduce them to stronger light sources.
- Start with low-intensity LED, CFL, or indirect sunlight, then gradually increase exposure.
Keep grow lights at a safe distance:
- LEDs: 12-24 inches (30-60 cm) above seedlings.
- HPS/MH: 24-36 inches (60-90 cm) above seedlings.
If transitioning to outdoor sunlight:
- Harden seedlings off gradually by placing them outside for short periods each day.

Additional Tips

Use filtered rainwater, bottled water, or dechlorinated tap water.
Maintain humidity levels between 70-80% for optimal germination.
Avoid handling the taproot directly, as it is delicate and can be easily damaged.
If using rockwool cubes, pre-soak them in pH 5.5 water before planting.
Germination rates depend on strain genetics, seed age, and storage conditions.
Seeds may take longer to sprout if conditions are too dry, cold, or hot.
Failure to follow these steps may reduce germination success and replacements are unlikely.
By following these steps, you’ll achieve healthy, vigorous cannabis seedlings ready for strong growth. 🌱