The Ultimate 90-Day Autoflower Cannabis Grow Guide [Seed to Harvest]
If you’re looking for the best autoflower grow guide, you’re in the right place. Autoflowers are unique because they grow on their own internal clock. Unlike photoperiod cannabis, which requires light cycle changes to flower, feminized autoflower cannabis seeds go from seed to harvest in about 90 days, regardless of light schedule.
That makes them a great option for beginners and seasoned growers alike — fast, compact, and less complicated. But to maximize yield, flavor, and potency, you’ll want to follow a consistent plan.
This post is your complete 90-day autoflower daily cannabis grow checklist, broken down into easy phases. Plus, we’ll cover FAQs, common mistakes, and tips to help you get the most from your plants.
🚀 Why Grow Autoflowers?
Autoflowers are becoming increasingly popular, and for good reason:
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Fast turnaround — most are ready in 70–90 days.
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Compact size — ideal for stealth or small spaces.
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Resilient genetics — many strains resist pests, mold, and stress.
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No light cycle changes — they flower automatically under 18–24 hours of light.
If you want a hassle-free grow that doesn’t sacrifice quality, autoflowers are one of the best cannabis options.
🌱 Phase-by-Phase Autoflower Grow Planner
Phase 1: Germination & Seedling (Days 1–14)
The first two weeks determine your plant’s future health. Think of this stage as laying the foundation.
Daily Checklist:
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Keep environment warm (75–80°F) and humid (65–70%).
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Use distilled or filtered water, pH 6.0–6.5.
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Provide 18–20 hours of light.
Steps:
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Day 1–2: Germinate seeds in a paper towel or starter plug.
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Day 3–7: Move sprouted seeds into final pots (3–5 gallon fabric pots are best). Autoflowers dislike transplanting, so start them in their forever home.
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Day 7–14: First true leaves appear. Begin ¼-strength nutrients.
Pro Tip: Keep lights 18–24 inches above seedlings. Too close = light stress; too far = stretching.
Phase 2: Vegetative Growth (Days 15–30)
Autoflowers don’t stay in veg long, but these two weeks are crucial for building structure before flowering begins.
Daily Checklist:
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Water every 2–3 days or when the top inch is dry.
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Keep temps 72–78°F, RH 55–65%.
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Train branches with LST (low-stress training) to spread the canopy.
Steps:
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Nutrients: Move to ½ strength by Week 3. Add Cal-Mag if using LEDs.
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LST: Gently bend and tie down the main stem around Day 18–21. This encourages more bud sites.
Pro Tip: Avoid topping or high-stress training. Autoflowers have limited time, and recovery eats into yield.
Phase 3: Pre-Flower & Stretch (Days 31–45)
This is when things get exciting. Your plant starts showing pistils and stretching rapidly.
Daily Checklist:
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Adjust LST as branches stretch.
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Begin bloom nutrients (start at ½ strength).
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Maintain 72–78°F, RH 45–55%.
Steps:
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Remove large fan leaves blocking bud sites.
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Keep watering consistent — roots need oxygen, so don’t overwater.
By the end of Week 6, you’ll see dozens of bud sites forming.
Phase 4: Flowering (Days 46–75)
Now the plant’s focus is all on bud development. Patience and consistency will pay off.
Daily Checklist:
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Check soil moisture every day. Water every 2–3 days.
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Feed bloom nutrients with extra phosphorus & potassium.
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Defoliate lightly to prevent humidity pockets.
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Keep RH at 40–50%.
Steps:
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Around Day 50, add bloom boosters.
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Watch trichome development closely by Day 60.
By the end of this stage, buds will be swelling, sticky, and covered in trichomes.
Phase 5: Ripening & Flush (Days 76–90)
The final stretch. Don’t rush — letting buds ripen properly makes all the difference.
Daily Checklist:
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Flush with plain, pH’d water starting Day 76.
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Check trichomes daily:
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Clear = not ready
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Cloudy = peak potency
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10–20% amber = more sedative effect
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Keep RH at 35–45%, temps at 70–75°F.
Steps:
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Around Day 85–90, your autoflower should be ready to harvest.
Pro Tip: Use a jeweler’s loupe or USB microscope for trichome checks. Pistil color alone isn’t reliable.
🌿 Harvest & Curing
Harvest isn’t the end — it’s half the battle. Poor drying or curing can ruin good buds.
Steps:
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Cut plants at the base and hang branches in a dark room (60–65°F, 50–55% RH).
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Dry for 7–10 days until stems snap.
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Trim buds and cure in airtight glass jars.
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Burp jars daily for 2 weeks, then weekly for up to 2 months.
Result: Smooth, flavorful, potent buds that burn clean.
⚡ Autoflower Grow FAQs
Q: How much do autoflowers yield?
A: Yields range from 1–4 oz per plant indoors, and much more outdoors in optimal conditions. Genetics, pot size, and care are the biggest factors.
Q: Can I grow autoflowers outdoors?
A: Yes — autoflowers thrive outdoors and finish quickly, making them perfect for short summers or multiple harvests per season.
Q: Do autoflowers need 12/12 light to flower?
A: No — they flower automatically under 18–24 hours of light. Many growers keep them at 20/4.
Q: What’s the best soil for autoflowers?
A: Light, well-aerated mixes (like coco + perlite) work best. Avoid heavy soils that suffocate roots.
❌ Top 7 Autoflower Growing Mistakes to Avoid
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Starting in small pots — Autoflowers don’t like transplanting.
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Overfeeding — Start nutrients at ¼ strength.
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Overwatering — Roots need oxygen; let the top inch dry before watering.
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Too much training — Autoflowers have no time to recover. Stick to LST.
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Ignoring pH — Keep water between 6.0–6.5.
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High humidity in flower — Leads to mold and bud rot.
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Harvesting too early — Wait until trichomes are cloudy/amber.
🏆 Final Thoughts
A 90-day cannabis grow with autoflowers is not only possible — it’s one of the easiest ways to produce quality buds at home. By following this daily cannabis grow checklist, you’ll take your plant from seed to sticky harvest in just three months.
The key is consistency: keep your lighting, nutrients, and environment steady, and your autoflower will reward you with potent, resinous buds.
Whether you’re growing one plant in a closet or a full indoor tent, this autoflower grow guide gives you the roadmap to success.