Fast Growing Weed Seeds for Quick Harvests

Introduction: Why Fast Growing Weed Seeds Matter
Not every grower has time for 12-week flowering cycles. Whether you’re racing against a short season, avoiding mold in humid climates, or just eager to smoke your own bud—fast growing weed seeds are your best friend.
In this guide, we’ll break down the quickest cannabis strains from Hypno Seeds that still deliver quality, yield, and high THC. These are perfect for beginner growers, stealth setups, or anyone craving a faster turnaround without sacrificing potency.
TL;DR: Top Fast Growing Weed Seeds
- Quickest Auto: Rainbow Runtz Auto – ~8 weeks
- Fastest Feminized: Purple Runtz – 8–9 weeks
- Best Outdoor Option: Mimosa – finishes strong in warm zones
- Easy Indoor Grow: Gelato 33
- Great for impatient growers, short seasons, or stealth setups
- Don’t forget to read our Germination Guide
What Makes a Weed Seed Grow Fast?
When we talk about fast growing weed seeds, we’re talking about strains that reach harvest faster than average—without compromising quality.
Several traits contribute to speed:
Short Flowering Time
Most fast strains finish flowering in 8 to 9 weeks. Some autoflowers can go from seed to harvest in just 8–10 weeks total.
Autoflowering Genetics
These strains automatically switch from veg to flower after 3–4 weeks—no light schedule required. This cuts weeks off your grow cycle.
Compact Growth
Smaller plants mature faster. Many fast growing weed seeds are also short and bushy, making them perfect for indoor or balcony grows.
Strong Resistance
Fast harvests also mean less time for pests, mold, or mistakes. Beginner growers benefit from sturdy, low-maintenance plants.
Best Fast Growing Weed Seeds from Hypno Seeds (Autoflowers)
If you’re looking for the fastest turnaround possible, autoflowers are the way to go. These fast growing weed seeds skip the waiting game—flowering automatically and finishing in record time.
Here are our top picks:
Rainbow Runtz Auto
- Total Time: ~8 weeks from seed
- Flavor: Fruity, sweet, citrus
- THC: ~20%
- Grow Tip: Start in final container—autos don’t like transplants
- Best Outdoor Zones: CA, FL, TX
✅ The fastest growing strain in our catalog. Ideal for impatient growers.
Crystal Ball Auto
- Total Time: ~8–9 weeks from seed
- Flavor: Sweet, berry, earthy
- THC: ~20–22%
- Grow Tip: Keep temps stable during flowering to boost resin production
- Best Outdoor Zones: CA, TX, FL
✅ Easy to grow, magical flavor, and delivers a fast, satisfying harvest.
Z Autoflower
- Total Time: ~8–9 weeks from seed
- Flavor: Berry, candy, tropical
- THC: ~20%
- Grow Tip: Keep light intensity moderate to avoid foxtailing in flower
- Best Outdoor Zones: CA, AZ, FL
✅ Delivers rich Zkittlez flavor in a fast, easy-growing autoflower package.
Fast Growing Feminized Weed Strains
While autoflowers are the quickest from seed to stash, some feminized strains also offer short flowering times with high yield potential. These are great for growers who want fast growing weed seeds that still allow training, bigger size, and a bit more control.
Here are the top fast-flowering feminized picks from Hypno Seeds:
Gelato 33
- Flowering Time: 8–9 weeks
- Flavor: Creamy, citrus, vanilla
- THC: ~25%
- Grow Tip: Use SCROG or LST to maximize space and yield
- Best Outdoor Zones: CA, OR, VA
✅ Fast, flavorful, and ideal for indoor growers wanting high potency.
Sunset Runtz
- Flowering Time: 8–9 weeks
- Flavor: Tropical, sweet, floral
- THC: ~26%
- Grow Tip: Keep temperatures warm during flower to boost terpenes
- Best Outdoor Zones: CA, AZ, NC
✅ A beginner-friendly strain that finishes fast with stunning bag appeal.
Purple Runtz
- Flowering Time: 8–9 weeks
- Flavor: Grape, candy, earthy
- THC: ~29%
- Grow Tip: Slightly reduce temps at night to intensify colors
- Best Outdoor Zones: GA, NM, TX
✅ A powerful hybrid with fast flowering and show-stopping color.
Tips for Speeding Up Your Grow (Without Sacrificing Quality)
Want to take full advantage of fast growing weed seeds? These pro tips will help you speed things up even more—while keeping yields and potency high.
1. Start With the Right Genetics
Choose autoflowers or quick-flowering feminized strains for faster results.
Browse Autoflowering Seeds
Explore Feminized Seeds
2. Use Feminized or Autoflower Seeds
No time wasted identifying males. Autoflowers switch to flower on their own; feminized seeds guarantee bud-producing females.
3. Germinate the Right Way
Use the paper towel method for the quickest and most reliable results. 📖 Follow our Germination Guide.
4. Optimize Your Light Cycle
- Autoflowers: 18/6 or 20/4 light cycle from start to finish
- Photoperiods: 18/6 for veg, switch to 12/12 for flower
Use full-spectrum LEDs for faster, denser growth.
5. Dial In Temps & Humidity
Ideal conditions for fast growth:
- Temp: 72–78°F (22–26°C)
- Humidity: 55–65% veg, 40–50% flower
6. Harvest on Time
Don’t harvest early. Watch trichomes closely—cloudy or amber = ready. Rushing here can ruin the whole grow.
Start Your Grow with the Fastest Weed Seeds on the Market
Whether you’re working with a tight schedule, a stealthy setup, or just want quick results—fast growing weed seeds are your best bet.
From autos like Rainbow Runtz Auto to fast-flowering feminized stars like Purple Runtz, Hypno Seeds has everything you need to grow high-quality buds in less time.