Washington’s Weed Timeline: Planting, Pruning, and Harvesting by Region

Growing cannabis in Washington is like growing in three different states at once. From the fog-wrapped coastlines of the Olympic Peninsula to the sunbaked soil of the Columbia Basin, each region comes with its own rhythms, microclimates, and critical calendar dates.

This is your go-to, regional breakdown of when to plant, prune, and harvest cannabis throughout Washington, with tips for adapting to your local conditions and maximizing your yields.

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Understanding Washington’s Regional Growing Zones

Let’s divide the state into three practical zones for homegrowers:

1. Western WA (Coastal/Maritime) – Seattle, Olympia, Bellingham, Port Angeles

2. Central WA (Foothills & Elevation) – Wenatchee, Cle Elum, Yakima Highlands

3. Eastern WA (Inland/Arid) – Spokane, Walla Walla, Tri-Cities, Pullman

Each zone has different sunlight, temperature patterns, rainfall, and grow season length.

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Planting: Timing the Start of Your Grow

Western WA (Cool, Cloudy, Wet)

• Start Indoors: Late March – Mid April

• Transplant Outdoors: May 15 – June 1 (wait for 50°F+ nights)

• Direct Sow Autoflowers: May 20 – June 10

• Tips:
   – Use raised beds to combat soggy soil
   – Protect from May-June slugs and early mildew
   – Choose early-finishing, mold-resistant strains

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Central WA (Cool Nights, Bright Days, Shorter Season)

• Start Indoors: March 20 – April 5

• Transplant Outdoors: May 5 – May 20 (watch elevation frost risk)

• Direct Sow Autoflowers: May 10 – June 5

• Tips:
   – Use black fabric pots to warm the root zone
   – Windbreaks are essential
   – Great for colorful strains—cold nights trigger purpling

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Eastern WA (Hot, Dry, Long Season)

• Start Indoors: March 1 – March 20

• Transplant Outdoors: April 25 – May 15 (safe from frost)

• Direct Sow Autoflowers: May 1 – May 20

• Tips:
   – Mulch early to retain moisture
   – UV exposure is higher—expect extra trichomes
   – Best zone for sativa-dominant strains and big yields

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Pruning & Training: When to Shape for Size and Airflow

Late May – Early July: Vegetative Phase

Regardless of region, this is prime time for pruning, topping, and training.

Techniques by Region:

• Western WA
   – Focus on opening the canopy to prevent mildew
   – Remove bottom fan leaves early
   – Use SCROG if growing under a shelter

• Central WA
   – Expect vigorous vertical growth—use topping and LST
   – Remove large fans gradually to reduce sun blockage

• Eastern WA
   – Use supercropping to control height and windbreaks
   – Consider trellising for sativas or multi-cola plants

Always finish your aggressive pruning by early July—late cuts can stress the plant as it prepares to flower.

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Flowering Window: Know When Buds Begin

Flowering typically starts when daylight drops below ~14 hours, which happens around early August across the state.

• Autoflowers begin on their own ~3–5 weeks from sprout

• Photoperiod plants start blooming mid-August and peak in early September

Regional Considerations:

• Western WA – Watch for botrytis and bud rot mid-August onward

• Central WA – Nights cool fast—strain selection matters

• Eastern WA – Ideal flowering conditions; monitor for heat spikes and mites

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Harvesting: When to Cut for Potency and Prevention

Target Harvest Dates by Region

• Western WA

• Ideal Harvest Window: Sept 25th - Oct 10th
• Risks If Delayed: Bud rot, early rain, cold snaps

• Central WA

• Ideal Harvest Window: Sept 20th - Oct 5th
• Risks If Delayed: Mold, frost in early October

• Eastern WA

• Ideal Harvest Window: Oct 1st - Oct 15th
• Risks If Delayed: Freeze mid-October, low humidity

Harvest Tips:

• Track trichomes: Cloudy with 10–30% amber = peak potency

• Don’t wait for full fade in rainy regions—take them early if needed

• Use drying tents or garages if outdoor drying is impossible due to moisture

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Bonus Tip: Consider a Staggered Schedule

In Washington’s unpredictable climate, it pays to stagger your plants:

• Start early autoflowers for August harvest

• Plant main photoperiods for late September

• Keep a backup clone or fast-finishing strain in a container you can bring under shelter in October

This approach spreads risk, ensures at least one successful pull, and lets you experiment with multiple harvest windows.

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Grow with the Region, Not Against It

There’s no one-size-fits-all calendar in Washington. From wind-swept orchards in Chelan to shaded suburban plots in Tacoma, your success comes from understanding how your local climate and elevation shape your grow schedule.

Adapt to your region. Learn your microclimate. And don’t be afraid to tweak the timeline from year to year—Washington’s weather always keeps us on our toes.

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We help homegrowers turn backyard dreams into cured jars—rain or shine, east or west. From cloudy coastlines to dusty hills, we provide regional timelines, strain suggestions, and step-by-step support tailored to your corner of Washington. Check out our website for more tips.