GrapeFruit Matic 420 Fast Buds – Fast Autoflowering Citrus Strain with 19% THC · High-Yield Indoor & Outdoor

GrapeFruit Matic 420 Fast Buds is a lightning-fast autoflowering strain that delivers big flavor, solid potency, and impressive yields without demanding expert skills—perfect for your next grow, whether you're in a closet or a backyard.

Struggling with slow, finicky plants?

You’ve probably dealt with strains that take forever to mature, demand perfect conditions, or collapse at the first sign of stress. You invest weeks of care only to end up with airy buds, weak flavor, or disappointing harvests. It’s frustrating when your time and effort don’t pay off.

What if your next grow was stress-free and packed with flavor?

Imagine harvesting frosty, citrus-scented buds in under ten weeks—no complicated light schedules, no delicate pruning, and no fear of mold or pests derailing your crop. Picture a plant that grows strong on its own, shrugs off minor mistakes, and rewards you with smooth, uplifting smoke every time.

GrapeFruit Matic turns that into reality

This autoflowering powerhouse from FastBuds hits harvest in just 65 days from seed, producing up to 600 g/m² indoors or 300 g per plant outdoors. With a zesty grapefruit aroma, 19% THC, and a balanced sativa-dominant high, it’s built for flavor lovers and efficient growers who want quality without the hassle.

Before You Plant GrapeFruit Matic

Setting up for success starts with the right space and gear. Whether you're growing indoors under LED or outdoors in a sunny spot, this strain thrives with minimal fuss—but a little prep goes a long way. Choose a well-draining soil or coco mix, and make sure your space gets consistent light and airflow.

• Start with a final pot size of 18–27 L (0.63–0.95 ft³) to avoid transplant stress
• Use a balanced, light fertilizer for autoflowers from day one
• Keep humidity at 60–70% during germination and seedling stage
• Ensure 18–20 hours of light daily—no switching required
• Check pH: 6.0–6.5 for soil, 5.8–6.2 for coco or hydro

During Growth: Watch It Explode

GrapeFruit Matic grows fast and furious, shooting up to 0.80–1.10 m (2.62–3.61 ft) with a bushy, jungle-like structure. You’ll notice the citrus terps early, and by week 4, the plant enters flowering automatically. No stress, no switches—just steady growth and increasing resin production.

Keep watering moderate and avoid topping or aggressive training—this is an auto, after all. Instead, use gentle LST to open up the canopy and boost light penetration. As buds form, you’ll see them pack on weight and sparkle with trichomes.

After Harvest: Flavor, Potency & Easy Maintenance

Once cured, GrapeFruit Matic delivers a smooth, creamy smoke with a bold grapefruit kick and subtle earthy undertones. The high is uplifting and creative at first, then mellows into relaxed clarity—perfect for daytime or social moments.

After harvest, clean your space and sterilize tools. The plant residue? Save the trim—it’s potent enough to make extracts or edibles. This strain leaves you not just with top-shelf bud, but with confidence for your next grow.

Short- and Long-Term Advantages

• Harvest in just 65 days—ideal for quick turnover or multiple cycles per year
• High resistance to mold and pests, even in humid climates
• Consistent yields season after season, indoors or outdoors
• Low nutrient demand—saves money and reduces burn risk
• Minimal odor during growth, great for discreet setups
• Smooth, flavorful smoke that impresses connoisseurs
• Great for beginners—forgives common mistakes like overwatering
• Perfect for micro-grows or stealth gardens thanks to compact height

Technical specifications

• Breeder / Brand: FastBuds
• Type: Autoflowering
• Dominance: Sativa-dominant hybrid
• Genetics: Sour Citrus × Ruderalis
• Crop cycle: 65 days from germination
• Indoor yield: 400–600 g/m² (14.11–21.16 oz/ft²)
• Outdoor yield: Up to 300 g/plant (10.58 oz/plant)
• Indoor height: 0.80–1.10 m (2.62–3.61 ft)
• Outdoor height: 0.80–1.10 m (2.62–3.61 ft)
• Difficulty: Low
• Structure: Bushy, dense branching, moderate stretch
• Climate: Temperate, Mediterranean, continental
• Resistance: High resistance to mold, pests, and water stress
• Training: Suitable for LST; avoid topping or FIM
• Recommended pot: 18–27 L final pot (early placement)
• Light cycle: 18–20 h daily throughout life
• Smell in grow: Medium (carbon filter recommended in confined spaces)
• THC: 19%
• CBD: 1%
• Aromatic profile: Limonene, myrcene, pinene
• Flavour: Citrus, grapefruit, sweet-tart, earthy
• Effect: Cerebral, uplifting, creative, followed by mellow relaxation

How to Grow GrapeFruit Matic Successfully

Get the most out of your GrapeFruit Matic with this expert-backed grow guide—simple, effective, and tailored to its autoflowering nature.

Quick overview

FastBuds’ GrapeFruit Matic is a low-difficulty, sativa-leaning auto ready in 65 days. Ideal for indoor tents or outdoor patios in temperate climates.

• Autoflowering – no light cycle changes needed
• Ready in ~9–10 weeks from seed to harvest
• Thrives in soil or coco with moderate feeding
• Best in 18–27 L pots to maximize root space
• Perfect for stealth grows or beginner-friendly setups

Safe start

Launch strong with a solid root foundation and early vigor.

• Germinate seeds in moist paper towels at 22–25 °C (71.6–77 °F)
• Transplant carefully when radicle reaches ~1 cm (0.39 in)
• Use a light, airy soil mix with perlite for drainage
• Water lightly—just enough to keep medium damp
• Boost root development with Startrex BioTabs at planting

Stable seedling

Keep young plants healthy and on track for explosive growth.

• Provide 18–20 hours of light daily with full-spectrum LEDs
• Maintain humidity at 60–70% for first 1–2 weeks
• Keep temps between 22–26 °C (71.6–78.8 °F)
• Begin mild nutrient feeding after first true leaves appear
• Support root health with Mygal (Mycorrhizal gel) for faster uptake

Directed growth

Guide structure and maximize light exposure without stress.

• Use low-stress training (LST) to spread branches early
• Avoid topping, FIM, or aggressive pruning—autos don’t recover well
• Keep EC progressive—start low, increase slightly in late veg
• Ensure pH stays in ideal range: 6.0–6.5 (soil), 5.8–6.2 (coco)
• Enhance terpene production with Fulvic-Blast during late veg

Efficient flowering

Maximize bud density, resin, and flavor in the final stretch.

• Reduce humidity to 40–50% to prevent mold
• Ensure strong airflow with oscillating fans
• Switch to bloom-focused nutrients at first pistils
• Add a PK booster like Mega Pk at peak flowering
• Flush with plain water 7–10 days before harvest

Harvest, drying and curing

Nail the finish for maximum potency and smoothness.

• Harvest when 70% of trichomes are milky, 30% cloudy
• Dry slowly at 18–22 °C (64.4–71.6 °F) and 50–60% RH
• Cure in glass jars for 2–4 weeks, burping daily
• Trim carefully—this strain produces resinous, dense colas
• Store cured buds in airtight containers away from light

Frequently Asked Questions

How long does GrapeFruit Matic take to grow?

From seed to harvest, GrapeFruit Matic takes about 65 days—just over nine weeks. No light cycle changes are needed, making it perfect for beginners.

What size pot should I use?

Use a final pot size of 18–27 L (0.63–0.95 ft³). Since it’s an autoflower, avoid transplanting—start in the final container.

Does it smell strong during flowering?

The smell is medium intensity—citrusy and sweet, but noticeable. In enclosed spaces, use a carbon filter like those in Deeper Underground setups to stay discreet.

Can I grow it outdoors in a cold climate?

Yes, it’s resilient to cooler temps and mold, but performs best in temperate or Mediterranean climates. Start in late spring or early summer for best results.

Is it good for beginners?

Absolutely. It’s forgiving of common mistakes like overwatering, nutrient imbalances, or minor climate swings—plus, it grows fast and delivers consistent results.

Personal Experience of Pevgrow’s CEO (Alan)

I grew GrapeFruit Matic in my 120x120x200 cm tent under a 600W HPS, one plant per 20L pot. I started with Startrex BioTabs and added Mygal at transplant—roots exploded in two weeks. I kept 18/6 lighting, watered every 2–3 days, and used a light organic base.

By week 4, it was flowering—no switch, no stress. I did light LST to open the canopy and saw trichomes going crazy by week 8. I flushed for 10 days, dried slowly, and cured for three weeks. Yield? 580 g/m² of frosty, citrus-packed bud. The high was clean, creative, and lasted hours without anxiety. I’ve grown dozens of autos—this one’s in my top 5. I’ll definitely grow it again.