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Cowlitz County, WA — Planting Guide

Cowlitz County, Washington Zone 8b June

June in Cowlitz County, Washington — your action list

A quick June briefing for Cowlitz County, Washington gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 15
Avg. first frost October 29
Soil temp (4") 82°F
Watering High
Pest pressure High
Daylight 15.6 hrs
  1. Time to start basil, peppers, and pole beans inside

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Start harvesting basil, carrots, and cucumber

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

July will be here before you know it — start on
  • First harvests: basil, carrots, and cucumber

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Cowlitz County is in USDA Zone 8b. The average last spring frost is April 15 and the first fall frost is October 29, giving you a growing season of approximately 197 days.

At an elevation of 268 ft, Cowlitz County receives approximately 47.4 in of rainfall annually. Summer highs average 87°F with winter lows around 42°F. The predominant soil type is Silt Loam.

Based on 31 years of NOAA climate station data, the last frost date here varies by 43 days year to year — ranging from March 24 in warm years to May 7 in cold years. The growing season is trending shorter by about 4.1 days per decade. Cowlitz County scores 63/100 (Good) on the Microclimate Index.

🌡️ Zone

8b (15°F to 20°F min)

❄️ Last Frost

April 15

🍂 First Frost

October 29

📅 Growing Season

197 days

⛰️ Elevation

268 ft

🌧️ Annual Rainfall

47.4 in

Cowlitz County, WA Moderate season
197 days
Last Spring Frost April 15
197 growing days
First Fall Frost October 29

Monthly Watering Calendar for Cowlitz County

When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.

Why it matters: Watering math is simple: 1 inch of rainfall delivers ~600 gallons to a 1,000 sq ft garden. Cowlitz County's 47" annual rainfall covers some months entirely; others need a few hours of drip irrigation per week. The calendar tells you which is which.

1"/wk 0" 1.9" 3.9" 5.8" 7.7" Jan 7.2" Feb 4.6" Mar 5.1" +0.7" Apr 3.6" +1.4" May 2.9" +2.3" Jun 2" +3.5" Jul 0.8" +3.4" Aug 0.9" +2.7" Sep 1.6" +0.9" Oct 3.4" Nov 7.6" Dec 7.7"
Rainfall sufficient Supplemental water needed Heavy watering required - - - 1"/week garden need
View detailed monthly data
MonthAvg RainfallRainy DaysExtra Water NeededWatering Effort
Jan 7.2 in 18 days None
Feb 4.6 in 12 days Low
Mar 5.1 in 15 days Low
Apr 3.6 in 13 days 0.7 in Moderate
May 2.9 in 10 days 1.4 in Moderate
Jun 2 in 6 days 2.3 in High
Jul 0.8 in 3 days 3.5 in Critical
Aug 0.9 in 2 days 3.4 in Critical
Sep 1.6 in 5 days 2.7 in High
Oct 3.4 in 11 days 0.9 in Moderate
Nov 7.6 in 14 days Low
Dec 7.7 in 18 days None

Annual total: 47.4 in. Water needs vary by crop — tomatoes need ~1.2"/week while herbs like rosemary need only 0.3"/week. Check individual plant pages for crop-specific water budgets that factor in your county's rainfall and soil drainage.

Cowlitz County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Frost Risk Probability

Based on 31 years of NOAA weather station data from 3 stations

Too early frost risk Safe to Plant Apr 15 → Oct 29 197 frost-free days Protect crops frost returns Mar Apr May Jun Jul Aug Sep Oct Nov Dec Safe: May 7 Protect by: Nov 24

Beginners: Plant frost-sensitive crops (tomatoes, peppers, squash) after the "Safe" date on the left. Harvest or cover them before the "Protect by" date on the right. Hardy crops (lettuce, peas, kale) can go in the yellow transition zones.

How to read this table: "Conservative" means you're safe from frost 9 out of 10 years — best for beginners and frost-sensitive crops. "Average year" is the typical date. "Aggressive" means only 1 in 10 years is that warm — experienced gardeners with frost protection can try these dates.

Planting Strategy Last Spring Frost First Fall Frost Frost-Free Days
Conservative (safest) May 7 Nov 24 201 days
Cautious Apr 24 Nov 7 197 days
Average year Apr 15 Oct 29 197 days
Optimistic Apr 9 Oct 20 194 days
Aggressive (risky) Mar 24 Oct 9 199 days
📊
How predictable are frost dates here?

Not very — frost dates can vary by ±43 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.

⚠️
Is the growing season changing?

Yes — growing seasons are getting shorter here (about 4.1 days per decade). Use the "Conservative" dates and choose fast-maturing varieties.

Gardening Difficulty Score

63 Good
Frost Timing Risk
10.0/10
Drought Risk
1.5/10
Soil Difficulty
0.0/10
Altitude Challenge
0.0/10
Climate Shift
10.0/10
Rainfall Challenge
1.0/10

Cowlitz County offers good growing conditions. A little planning around frost dates goes a long way.

Zone 8b Frost Countdown
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Last Frost: Apr 15 First Frost: Oct 29

Local Gardening Help in Cowlitz County

Free expert help is closer than you think. Your county's cooperative extension office connects you with trained gardeners, soil testing labs, and local programs — all specific to Cowlitz County's climate and soil.

County Extension Office

Cowlitz County Washington State University Extension Extension Office

Phone: 509-335-2811

Visit Extension Office Website →

Extension offices are run by land-grant universities and funded by the USDA. Their advice is free, research-based, and tailored to your county's specific conditions.

Master Gardener Program

Free gardening help from trained volunteers

Master Gardeners are community volunteers who complete 40–60 hours of university horticultural training. They answer gardening questions, diagnose plant problems, and offer workshops — all free.

Find Master Gardeners in WA →

Many extension offices run a Master Gardener hotline where you can call or email with photos of plant problems for free diagnosis.

Soil Testing

Available through your extension office

Before amending your soil, get it tested. Your extension office offers soil testing (typically $10–$25) that tells you exact pH, nutrient levels, and amendment recommendations specific to what you want to grow.

Request a Soil Test →

Services Available in Cowlitz County

Soil testing Pacific NW gardening Master Gardener hotline
Finding local nurseries & garden centers in Cowlitz County

Why Buy Local

Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Cowlitz County's soil and climate that big-box stores can't. Plants from local growers are typically hardier because they're already acclimated to your zone.

How to Find Them

Search for "nurseries near Cowlitz County WA" or "garden center Cowlitz County" on Google Maps. Also check with your extension office — they often maintain lists of reputable local nurseries and plant sales.

Community gardens & gardening groups

Community gardens are a great way to learn from experienced gardeners in your area, especially if you're limited on space. Search "community garden Cowlitz County WA" or check your extension office and local parks department. Facebook groups like "Cowlitz County Gardeners" or "Washington Gardening" are also excellent for local advice and plant swaps.

What to Plant After Your Harvest

After your first crops finish, use the remaining frost-free days to grow a second round.

Show 6 more succession options
After Lettuce (harvest ends Jul 29) 92 days until frost
After Spinach (harvest ends Jul 22) 99 days until frost
After Onion (harvest ends Sep 2) 57 days until frost
After Beets (harvest ends Jul 8) 113 days until frost
After Squash (Summer) (harvest ends Aug 19) 71 days until frost
After Cantaloupe (harvest ends Aug 19) 71 days until frost

Sunlight & Day Length in Cowlitz County

Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.

For new gardeners: Day length is the trigger that tells lettuce, spinach, and cilantro to bolt. In Cowlitz County, knowing when that day-length threshold arrives helps you plant a final round in time to harvest before it bolts.

Longest Day

15.6 hours

Summer solstice daylight

Shortest Day

8.4 hours

Winter solstice daylight

Peak Sun Hours

11 hr/day peak (summer)

Peak sun hours (green dashed line below) account for cloud cover — this is the usable direct sunlight your garden actually receives. Most vegetables need 6+ peak sun hours.

14hr 12hr 0h 4h 9h 13h 17h Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Daylight hours (sunrise to sunset) Peak sun hours (direct sunlight after cloud cover) ▪ Gold zone = long day (14+ hr) ▪ Blue zone = short day (<12 hr)

Onion tip: Your long summer days (14+ hours) support long-day onion varieties like Walla Walla, Sweet Spanish, and Ailsa Craig.

View detailed monthly data
MonthDaylight HoursPeak Sun HoursDay Length
January 8.8 hr 2.3 hr Short day
February 10.1 hr 3.1 hr Short day
March 11.6 hr 4 hr Short day
April 13.3 hr 5.3 hr Neutral
May 14.8 hr 7.8 hr Long day
June 15.6 hr 8.4 hr Long day
July 15.2 hr 11 hr Long day
August 14 hr 9.6 hr Long day
September 12.3 hr 7.5 hr Neutral
October 10.6 hr 4.1 hr Short day
November 9.2 hr 2.4 hr Short day
December 8.4 hr 1.8 hr Short day

Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.

Soil Temperature & Composting in Cowlitz County

Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.

For new gardeners: Air temperature lies. Your air can be 70°F in April but the soil 4 inches down is still 50°F — too cold for tomatoes or peppers to root properly. Cowlitz County's soil temperature curve tells you the real planting window. A $5 soil thermometer pays for itself in one season.

Plant Warm Crops When

Soil reaches 60°F+

Soil warm enough from Apr through Nov.

Best Month to Compost

May

Microbial activity peaks when soil is warm.

Active Composting

10 months

Nearly year-round composting.

60°F 70°F 30° 50° 70° 90° 110° Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
4" depth 8" depth - - - 60°F (corn, beans) - - - 70°F (tomatoes, peppers)
View detailed monthly data
MonthSoil 4" DeepSoil 8" DeepCompost ActivityTime to Finish
Jan 45°F 50°F 🐢 Slow ~24 weeks
Feb 44°F 48°F 🐢 Slow ~24 weeks
Mar 53°F 53°F ♻️ Active ~14 weeks
Apr 62°F 61°F ♻️ Active ~14 weeks
May 73°F 69°F 🔥 Peak ~8 weeks
Jun 83°F 76°F 🔥 Peak ~8 weeks
Jul 90°F 84°F 🔥 Peak ~8 weeks
Aug 91°F 85°F 🔥 Peak ~8 weeks
Sep 83°F 83°F 🔥 Peak ~8 weeks
Oct 71°F 75°F 🔥 Peak ~8 weeks
Nov 61°F 63°F ♻️ Active ~14 weeks
Dec 50°F 56°F ♻️ Active ~14 weeks

Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.

Pest & Disease Pressure in Cowlitz County

Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.

The practical takeaway: The most successful gardeners in high-pressure regions don't spray more — they design around the problem. Crop rotation, companion planting, and resistant varieties beat reactive spraying.

Insect Pest Pressure

7.2 / 10

High — expect multiple pest generations. Preventative measures essential.

Disease Risk

7.6 / 10

High fungal/bacterial risk. Space plants for airflow, water at soil level.

Seasonal Risk

Spring High
Summer High
Fall High
Winter Low
View 6 common pests in your area
PestRisk LevelPeak Months
Aphids High Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov
Squash vine borers Moderate May, Jun, Jul
Stink bugs High Apr, May, Jun, Jul, Aug, Sep, Oct
Whiteflies Moderate May, Jun, Jul, Aug, Sep, Oct
Spider mites High Jun, Jul, Aug, Sep
Fire ants Moderate Mar, Apr, May, Jun, Jul, Aug, Sep, Oct
Organic pest management tips
  • Install physical barriers: floating row covers, copper tape for slugs, mesh netting
  • Apply Bt (Bacillus thuringiensis) for caterpillar control — safe for beneficial insects
  • Use kaolin clay spray to deter a wide range of insects on fruiting crops
  • Release beneficial insects: ladybugs for aphids, parasitic wasps for caterpillars
  • Apply neem oil weekly during high-pressure months
  • Mulch heavily (3-4 inches) to reduce soil-borne disease splash

Cover Crops for Cowlitz County

Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with planting dates calibrated for your area.

What this means for you: Cover crops are the experienced gardener's secret weapon. Cowlitz County's climate determines which species thrive: clover and vetch in mild winters, cereal rye and Austrian peas in cold ones.

Spring Cover Crops (4 options) — Build soil before the main growing season
Crop Plant By Terminate N-Fixing Soil Benefit
Buckwheat Apr 19 Aug 20 Rapid growth, attracts pollinators, suppresses weeds
Cowpeas (southern peas) Apr 17 Aug 27 ✓ Yes Excellent nitrogen fixer for warm climates, edible
Sorghum-sudan grass Apr 23 Aug 20 Massive biomass, breaks compaction, suppresses nematodes
White clover Mar 17 Aug 20 ✓ Yes Living mulch, fixes nitrogen, permanent ground cover
Summer Cover Crops (1 options) — Fill gaps and suppress weeds between plantings
Crop Plant By Terminate N-Fixing Soil Benefit
Sunflowers May 11 Oct 1 Deep roots break compaction, attract pollinators and beneficial insects
Fall Cover Crops (7 options) — Plant after harvest to protect soil over winter
Crop Plant By Terminate N-Fixing Soil Benefit
Austrian winter peas Aug 21 Mar 25 ✓ Yes Fixes nitrogen, good for heavy clay soils
Crimson clover Aug 23 Mar 25 ✓ Yes Fixes nitrogen, attracts pollinators in spring
Daikon radish Sep 9 Apr 1 Deep taproot breaks compaction, excellent for clay soils
Hairy vetch Aug 12 Mar 25 ✓ Yes Excellent nitrogen fixer, good for depleted soils
Oats Sep 22 Apr 1 Quick biomass, winterkills in cold zones — no spring tillage needed
Winter rye Aug 5 Apr 1 Suppresses weeds, prevents erosion, breaks up compacted soil
Winter wheat Aug 9 Mar 25 Erosion control, weed suppression, good biomass

Wind & Microclimate in Cowlitz County

What this means for you: Why care about wind? Above about 10 mph, evaporation jumps and pollinators struggle to land on flowers. Cowlitz County's 9.1 mph average means you can plant tall crops without much support, but it doesn't mean ignore wind — a 20+ mph storm still snaps unstaked tomatoes.

Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.

Seasonal Wind Speed

Spring: 13 mph   Summer: 9 mph

Fall: 8 mph   Winter: 12 mph

Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.

Windbreak Benefit

5.5/10

Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.

Frost Pocket Risk

Moderate

Some terrain variation (510 ft range). Garden on slopes or higher ground if possible to avoid late-season frost pockets.

Rainwater Harvesting in Cowlitz County

How much water you can collect, when to collect it, and what size system you need for your garden.

Why it matters: A gravity-fed rain barrel ($75) is the easy entry. A larger cistern ($500-1500) covers a whole growing season. Cowlitz County's 47" annual rainfall determines whether the larger system is overkill or essential.

Annual Collection

23,624 gal

Per 1,000 sq ft of roof area (at 80% collection efficiency)

Recommended Setup

6 rain barrels (55 gal each)

For a typical 500 sq ft garden. Serious collectors: consider a 2,000 gal tank.

Legal Status

Unrestricted

Rainwater harvesting is fully legal in your state with no restrictions.

Best Collection Months

Jan, Mar, Nov, Dec

Highest rainfall months — your barrels will fill up quickly during these months.

Months to Draw From Storage

Jul, Aug

Dry months when you'll rely on stored water — size your storage for this gap.

Rainwater collection tips for your area
  • Your county receives approximately 47.4 inches of rain per year
  • A 1,000 sq ft roof can collect roughly 23,624 gallons annually
  • Rainwater harvesting is fully legal in your state
  • Use a first-flush diverter to keep roof debris out of your collection

Soil & Growing Conditions in Cowlitz County

Soil Type

Silt Loam

Soil pH 5.7–6.5 · Moderately Well Drained drainage

Native soil is well-suited to most vegetables and herbs with regular compost additions.

Watering Needs

Drought stress: 1.5/10

Cowlitz County has very low drought pressure. Natural rainfall usually meets garden needs — water only during extended dry spells.

Season Tips

197-day frost-free season

Plenty of time for warm-season crops. Start heat-lovers indoors 6–8 weeks before last frost to maximise your harvest window.

Your Free Printable Garden Planner

Plan every bed, every planting, every harvest — in one place. This 22-page printable includes your zone's planting calendar, a month-by-month task list, a seed inventory tracker, a harvest log, and succession-planting charts. Built to print, write in, and actually use all season.

Instant PDF download. No spam, unsubscribe any time.

Recommended for Your Garden

🧪
Soil Test Kit $12-25

Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.

📏
Digital pH Meter $10-20

Get instant, accurate soil pH readings to fine-tune your amendments.

🍂
Organic Compost $8-30

Boost soil fertility and structure with rich, well-aged organic compost.

🥬 Vegetables to Grow in Cowlitz County

114 vegetables that grow well in Zone 8b with planting dates for Cowlitz County.

Show all 114 vegetables with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Acorn Squash Mar 18 Apr 22 Apr 29 Jul 22 – Aug 26 80–100
Amaranth Feb 25 Apr 22 Apr 29 Jul 29 – Sep 16 90–120
Artichoke Apr 29 Sep 2 – Nov 11 120–180
Arugula Mar 11 Apr 1 Apr 15 Aug 20 May 20 – Jul 22 30–50
Asparagus Apr 29 730–1095
Beets Apr 1 Aug 20 May 27 – Jun 24 50–70
Belgian Endive Mar 11 Apr 1 Apr 15 Aug 20 Aug 5 – Sep 30 110–150
Bitter Melon Feb 25 Apr 22 Apr 29 Jul 1 – Aug 12 60–90
Black Beans Apr 22 Jul 22 – Sep 9 90–120
Bok Choy Mar 11 Apr 1 Apr 15 Aug 20 May 27 – Jul 1 40–60
Broccoli Mar 11 Apr 1 Apr 15 Aug 20 Jun 17 – Jul 29 60–90
Broccoli Rabe Mar 11 Apr 1 Apr 15 Aug 20 May 27 – Jul 1 40–60
Brussels Sprouts Mar 11 Apr 1 Apr 15 Aug 20 Jul 15 – Sep 9 90–130
Butternut Squash Mar 18 Apr 22 Apr 29 Jul 29 – Sep 2 85–110
Cabbage Mar 11 Apr 1 Apr 15 Aug 20 Jun 17 – Aug 12 60–100
Calabash Feb 25 Apr 22 Apr 29 Jul 22 – Sep 16 80–120
Cardoon Apr 29 Sep 2 – Oct 14 120–150
Carrots Apr 1 Aug 20 Jun 3 – Jul 8 60–80
Cauliflower Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Aug 12 55–100
Celeriac Mar 11 Apr 1 Apr 15 Aug 20 Jul 29 – Sep 2 100–120
Celery Mar 11 Apr 1 Apr 15 Aug 20 Jul 8 – Sep 2 80–120
Celtuce Mar 11 Apr 1 Apr 15 Aug 20 Jun 17 – Jul 29 60–90
Chard Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Jul 29 50–60
Chayote Feb 25 Apr 22 Apr 29 Sep 2 – Nov 11 120–180
Chickpeas Mar 11 Apr 1 Apr 15 Aug 20 Jul 8 – Aug 19 80–110
Chicory Mar 11 Apr 1 Apr 15 Aug 20 Jun 17 – Jul 29 60–85
Chinese Cabbage Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Jul 8 50–70
Christmas Lima Beans Feb 25 Apr 22 Apr 29 Jul 22 – Aug 26 80–100
Collard Greens Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Aug 12 55–75
Corn Apr 22 Jun 24 – Aug 19 60–100
Cowpeas Apr 22 Jun 24 – Aug 5 60–90
Cress Mar 11 Apr 1 Apr 15 Aug 20 Apr 29 – May 20 14–21
Crookneck Squash Mar 18 Apr 22 Apr 29 Jun 17 – Jul 15 45–60
Crosne Apr 1 Aug 20 Sep 2 – Nov 4 150–200
Cucumber Mar 18 Apr 22 Apr 29 Jun 24 – Aug 19 50–70
Daikon Apr 1 Aug 20 May 27 – Jun 24 50–70
Delicata Squash Mar 18 Apr 22 Apr 29 Jul 22 – Aug 26 80–100
Edamame Apr 22 Jul 8 – Aug 19 75–100
Eggplant Feb 11 Apr 22 Apr 29 Jul 8 – Sep 9 65–85
Endive Mar 11 Apr 1 Apr 15 Aug 20 Jun 3 – Jul 8 45–65
Escarole Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Jul 8 50–70
Fava Beans Mar 11 Apr 1 Apr 15 Aug 20 Jul 1 – Aug 12 75–100
Fennel Feb 25 Apr 22 Apr 29 Jul 1 – Aug 12 60–90
Garlic Sep 17 Dec 17 – Jun 3 90–240
Ginger Feb 25 Apr 22 Apr 29 Dec 30 – Jan 13 240–300
Green Beans Apr 22 Jun 17 – Aug 12 50–65
Horseradish Apr 29 Sep 2 – Nov 11 120–180
Hot Peppers Feb 11 Apr 22 Apr 29 Jul 8 – Oct 14 70–120
Hubbard Squash Mar 18 Apr 22 Apr 29 Aug 12 – Sep 16 100–120
Jicama Feb 25 Apr 22 Apr 29 Sep 2 – Nov 11 120–180
Kabocha Mar 18 Apr 22 Apr 29 Jul 29 – Aug 26 85–100
Kai Lan Mar 11 Apr 1 Apr 15 Aug 20 Jun 3 – Jul 1 45–60
Kale Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Aug 5 50–70
Kidney Beans Apr 22 Jul 22 – Aug 26 85–110
Kohlrabi Mar 11 Apr 1 Apr 15 Aug 20 Jun 3 – Jul 8 45–65
Komatsuna Mar 11 Apr 1 Apr 15 Aug 20 May 20 – Jun 24 35–50
Leeks Mar 11 Apr 1 Apr 15 Aug 20 Jul 15 – Sep 30 90–150
Lentils Mar 11 Apr 1 Apr 15 Aug 20 Jul 8 – Aug 19 80–110
Lettuce Mar 11 Apr 1 Apr 15 Aug 20 May 20 – Jul 29 30–60
Lima Beans Apr 22 Jun 24 – Aug 5 60–90
Loofah Feb 25 Apr 22 Apr 29 Aug 12 – Oct 14 100–150
Luffa Feb 25 Apr 22 Apr 29 Jul 29 – Oct 14 90–150
Mache Mar 11 Apr 1 Apr 15 Aug 20 May 27 – Jul 1 40–60
Malabar Spinach Feb 25 Apr 22 Apr 29 Jun 24 – Jul 22 55–70
Melon Mar 18 Apr 22 Apr 29 Jul 8 – Aug 26 70–100
Microgreens Mar 11 Apr 1 Apr 15 Aug 20 Apr 22 – May 20 7–21
Mitsuba Mar 11 Apr 1 Apr 8 Aug 20 Jun 3 – Jul 29 50–70
Mizuna Mar 11 Apr 1 Apr 15 Aug 20 May 20 – Jun 17 30–45
Mustard Greens Mar 11 Apr 1 Apr 15 Aug 20 May 20 – Jul 22 30–50
Napa Cabbage Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Jul 15 55–75
New Zealand Spinach Feb 25 Apr 22 Apr 29 Jun 24 – Jul 22 55–70
Okra Feb 25 Apr 22 Apr 29 Jun 24 – Aug 19 50–65
Onion Mar 11 Apr 1 Apr 15 Aug 20 Jul 15 – Sep 2 90–120
Pac Choi Mar 11 Apr 1 Apr 15 Aug 20 May 27 – Jun 24 40–55
Parsnip Apr 1 Aug 20 Jul 15 – Aug 26 100–130
Patty Pan Squash Mar 18 Apr 22 Apr 29 Jun 17 – Jul 15 45–60
Peas Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Aug 5 55–70
Peppers Feb 11 Apr 22 Apr 29 Jul 1 – Sep 9 60–90
Pole Beans Feb 25 Apr 22 Apr 29 Jun 24 – Aug 19 55–70
Potatoes Feb 25 Apr 22 Apr 29 Jul 8 – Sep 16 70–120
Pumpkin Mar 18 Apr 22 Apr 29 Jul 29 – Sep 16 85–120
Purslane Mar 11 Apr 1 Apr 15 Aug 20 May 27 – Jul 1 40–60
Radicchio Mar 11 Apr 1 Apr 15 Aug 20 Jun 17 – Jul 22 60–80
Radish Apr 1 Aug 20 Apr 29 – May 20 22–35
Rhubarb May 6 365–730
Romanesco Mar 11 Apr 1 Apr 15 Aug 20 Jul 1 – Aug 12 75–100
Rutabaga Apr 1 Aug 20 Jun 24 – Jul 29 80–100
Salsify Apr 1 Aug 20 Jul 15 – Aug 26 100–130
Savoy Cabbage Mar 11 Apr 1 Apr 15 Aug 20 Jun 24 – Aug 19 70–110
Scallions Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Jul 8 50–70
Scarlet Runner Beans Feb 25 Apr 22 Apr 29 Jul 1 – Aug 5 60–80
Shallot Mar 11 Apr 1 Apr 15 Aug 20 Jul 15 – Sep 2 90–120
Shiso Feb 25 Apr 22 Apr 29 Jun 24 – Aug 19 50–70
Snap Peas Feb 25 Apr 22 Apr 29 Jun 24 – Aug 19 55–70
Snow Peas Mar 11 Apr 1 Apr 15 Aug 20 Jun 10 – Aug 5 50–65
Soybeans Apr 22 Jul 15 – Sep 9 80–120
Spaghetti Squash Mar 18 Apr 22 Apr 29 Jul 29 – Aug 26 85–100
Spinach Mar 11 Apr 1 Apr 15 Aug 20 May 20 – Jul 22 35–50
Squash (Summer) Mar 18 Apr 22 Apr 29 Jun 17 – Aug 19 45–65
Squash (Winter) Mar 18 Apr 22 Apr 29 Jul 22 – Sep 16 80–120
Sunchoke Apr 29 Aug 19 – Oct 14 110–150
Sweet Corn Apr 22 Jun 24 – Aug 5 60–90
Sweet Potatoes Feb 25 Apr 22 Apr 29 Jul 29 – Sep 16 90–120
Tatsoi Mar 11 Apr 1 Apr 15 Aug 20 May 20 – Jun 24 35–50
Tomatillo Feb 25 Apr 22 Apr 29 Jul 1 – Sep 9 60–85
Tomatoes Feb 25 Apr 22 Apr 29 Jul 1 – Sep 9 60–85
Turmeric Feb 25 Apr 22 Apr 29 Dec 30 – Jan 13 240–300
Turnip Apr 1 Aug 20 May 13 – Jun 17 40–60
Watercress Mar 11 Apr 1 Apr 15 Aug 20 May 27 – Jul 1 40–60
Watermelon Mar 18 Apr 22 Apr 29 Jul 8 – Aug 26 70–100
Wax Beans Apr 22 Jun 17 – Aug 12 50–65
Winter Melon Feb 25 Apr 22 Apr 29 Jul 29 – Sep 16 90–120
Yard Long Beans Feb 25 Apr 22 Apr 29 Jun 24 – Aug 5 55–80
Zucchini Mar 18 Apr 22 Apr 29 Jun 17 – Aug 12 45–60

🍓 Fruits to Grow in Cowlitz County

27 fruits that grow well in Zone 8b with planting dates for Cowlitz County.

Show all 27 fruits with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Alpine Strawberries May 6 Aug 5 – Nov 18 90–180
Aronia May 6 730–1095
Blackberries May 6 365–730
Blueberries May 6 730–1095
Boysenberries May 6 365–730
Cantaloupe May 6 Jul 15 – Aug 19 70–90
Che Fruit May 6 1095–1825
Elderberries May 6 730–1095
Figs May 6 730–1825
Goji Berries May 6 730–1095
Gooseberries May 6 730–1095
Grapes May 6 730–1095
Ground Cherry May 6 Jul 15 – Sep 9 65–80
Hardy Kiwi May 6 1095–1825
Honeydew May 6 Jul 29 – Sep 9 80–110
Jostaberry May 6 730–1095
Kiwi May 6 1095–1825
Loquat May 6 730–1825
Medlar May 6 1095–1825
Mulberries May 6 730–1825
Pawpaw May 6 1095–2555
Persimmon May 6 1095–2555
Pomegranate May 6 730–1095
Quince May 6 1095–1825
Raspberries May 6 365–730
Serviceberries May 6 730–1095
Strawberries May 6 Aug 5 – Jan 20 90–365

🌿 Herbs to Grow in Cowlitz County

39 herbs that grow well in Zone 8b with planting dates for Cowlitz County.

Show all 39 herbs with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Harvest Days to Maturity
Angelica Mar 11 Apr 1 Apr 8 Aug 20 365–730
Anise Mar 11 Apr 1 Apr 8 Aug 20 Jul 8 – Sep 23 90–120
Basil Feb 25 Apr 22 Apr 29 Jun 24 – Aug 26 50–75
Bee Balm Apr 22 Jul 22 – Oct 7 90–120
Borage Mar 11 Apr 1 Apr 8 Aug 20 Jun 3 – Jul 22 50–60
Caraway Mar 11 Apr 1 Apr 8 Aug 20 365–450
Catnip Apr 22 Jun 24 – Aug 26 60–80
Chamomile Mar 11 Apr 1 Apr 8 Aug 20 Jun 10 – Aug 19 60–90
Chervil Mar 11 Apr 1 Apr 8 Aug 20 May 20 – Jul 22 40–60
Chives Apr 22 Jun 24 – Sep 2 60–90
Cilantro Mar 11 Apr 1 Apr 8 Aug 20 May 20 – Jul 22 40–60
Comfrey Apr 22 Jun 24 – Sep 2 60–90
Cumin Mar 11 Apr 1 Apr 8 Aug 20 Jul 22 – Sep 23 100–120
Dill Mar 11 Apr 1 Apr 8 Aug 20 May 20 – Jul 22 40–60
Epazote Feb 25 Apr 22 Apr 29 Jun 17 – Aug 12 45–60
Fennel (herb) Mar 11 Apr 1 Apr 8 Aug 20 Jun 10 – Aug 19 60–90
Feverfew Apr 22 Jul 22 – Oct 7 90–120
Garlic Chives Apr 22 Jun 24 – Sep 2 60–90
Horehound Apr 22 Jul 8 – Sep 2 75–90
Hyssop Apr 22 Jul 1 – Sep 2 70–90
Lemon Balm Apr 22 Jun 24 – Aug 12 60–70
Lemon Thyme Apr 22 Jul 1 – Sep 2 70–90
Lemon Verbena Feb 25 Apr 22 Apr 29 Jul 1 – Sep 9 60–90
Lemongrass Feb 25 Apr 22 Apr 29 Jul 15 – Oct 14 75–120
Lovage Apr 22 Jul 1 – Sep 2 70–90
Marjoram Apr 22 Jun 24 – Sep 2 60–90
Mint Apr 22 Jun 24 – Sep 2 60–90
Oregano Apr 22 Jun 24 – Sep 2 60–90
Parsley Mar 11 Apr 1 Apr 8 Aug 20 Jun 10 – Aug 12 60–80
Rosemary Apr 22 Jul 15 – Dec 2 80–180
Rue Apr 22 Jul 1 – Sep 2 70–90
Sage Apr 22 Jul 8 – Sep 2 75–90
Savory Apr 22 Jun 17 – Aug 12 50–70
Sorrel Mar 11 Apr 1 Apr 8 Aug 20 May 20 – Jul 22 40–60
Stevia Feb 25 Apr 22 Apr 29 Jul 1 – Sep 9 60–90
Tarragon Apr 22 Jun 24 – Sep 2 60–90
Thai Basil Feb 25 Apr 22 Apr 29 Jun 24 – Aug 26 50–75
Thyme Apr 22 Jul 1 – Sep 2 70–90
Valerian Apr 22 Aug 26 – Dec 2 120–180

🌸 Flowers to Grow in Cowlitz County

54 flowers that grow well in Zone 8b with planting dates for Cowlitz County.

Show all 54 flowers with planting dates
Plant Start Indoors Direct Sow Transplant Fall Plant Bloom Days to Maturity
Ageratum Mar 4 Apr 1 Apr 1 May 27 – Oct 28 60–75
Alliums Oct 1 Oct 29 – Nov 19 28–42
Anemones Sep 3 Sep 10 – Oct 8 90–120
Astilbe Feb 18 Apr 15 Jun 24 – Aug 12 70–100
Bachelor's Button Feb 25 Mar 25 Sep 3 May 27 – Sep 23 60–90
Begonias Feb 4 Apr 1 Jun 10 – Nov 11 70–90
Black-eyed Susan Feb 18 Apr 1 Apr 15 Jun 24 – Nov 18 60–80
Bleeding Hearts Feb 18 Apr 15 Jun 3 – Jul 1 60–90
Calendula Feb 25 Mar 25 Aug 20 May 13 – Oct 7 50–70
California Poppy Aug 20 Oct 29 – Feb 18 60–90
Celosia Mar 18 Apr 1 Apr 1 Jun 3 – Nov 11 60–90
Columbine Feb 18 Apr 15 Apr 15 Jun 3 – Jul 1 70–100
Coreopsis Feb 18 Apr 1 Apr 15 Jun 17 – Nov 11 60–80
Cosmos Mar 18 Mar 25 Mar 25 Jun 3 – Nov 4 60–90
Crocus Oct 1 Sep 3 – Sep 24 10–20
Daffodils Oct 1 Sep 10 – Oct 8 20–40
Dahlias Mar 25 Apr 15 Apr 15 Jun 24 – Dec 9 70–120
Daylily Feb 18 Apr 15 Jun 24 – Nov 25 60–90
Dianthus Feb 18 Feb 25 Mar 4 Apr 22 – Jul 1 60–80
Echinacea (Purple Coneflower) Feb 18 Apr 15 Apr 15 Jun 24 – Nov 11 70–90
Foxglove Feb 18 Apr 8 Apr 8 May 27 – Jun 24 80–120
Freesia Sep 17 Oct 8 – Nov 12 84–112
Gaillardia (Blanket Flower) Mar 4 Apr 1 Apr 1 Jun 10 – Nov 25 70–100
Geraniums Feb 4 Apr 1 Jun 10 – Nov 11 70–100
Gladiolus Apr 15 Apr 15 Jun 24 – Dec 9 70–100
Hostas Feb 11 Apr 15 Jun 24 – Oct 28 60–90
Hyacinths Oct 1 Sep 24 – Oct 15 14–28
Hydrangeas Feb 11 Apr 8 Jun 17 – Oct 21 90–150
Impatiens Feb 18 Apr 8 Jun 17 – Nov 18 60–75
Irises Division Apr 8 May 27 – Jul 1 60–100
Larkspur Aug 20 Oct 29 – Feb 18 60–90
Lavender Feb 18 Apr 15 Jun 24 – Sep 30 90–120
Lilies Division Apr 8 Jun 17 – Oct 7 70–120
Lobelia Feb 18 Mar 4 Apr 29 – Jun 10 70–80
Lupine Feb 18 Apr 15 Apr 15 Jun 3 – Jul 1 75–100
Marigolds Mar 11 Apr 1 Apr 1 May 27 – Oct 14 50–70
Nasturtium Mar 18 Apr 1 Apr 1 May 27 – Nov 11 55–65
Pansy Feb 4 Mar 25 Aug 20 May 20 – Sep 9 70–90
Peonies Division Apr 15 Jun 10 – Jul 8 90–120
Petunia Feb 18 Apr 8 Jun 17 – Nov 4 70–90
Phlox Feb 18 Apr 15 Apr 15 Jun 24 – Sep 2 80–110
Portulaca Mar 18 Apr 1 Apr 1 May 20 – Oct 28 50–70
Ranunculus Sep 3 Sep 17 – Oct 15 90–120
Roses Feb 11 Apr 8 Jun 17 – Nov 18 90–180
Salvia Feb 18 Apr 1 Jun 10 – Nov 11 70–90
Sedum (Stonecrop) Feb 18 Apr 15 Aug 5 – Oct 28 60–90
Snapdragon Feb 4 Mar 4 Mar 25 Aug 20 Jun 3 – Oct 7 70–100
Sunflower Mar 25 Apr 1 Apr 1 Jun 24 – Nov 11 70–100
Sweet Alyssum Mar 4 Mar 4 Mar 25 Sep 3 May 6 – Sep 9 45–60
Sweet Pea Aug 27 Nov 5 – Jan 14 65–85
Tulips Oct 1 Sep 17 – Oct 15 15–30
Vinca (Annual) Feb 4 Apr 1 Jun 10 – Nov 11 70–90
Yarrow Feb 18 Apr 1 Apr 15 Jun 17 – Nov 11 60–90
Zinnia Mar 18 Apr 1 Apr 1 Jun 10 – Nov 11 60–70

Monthly Planting Guide for Cowlitz County

Gardening Guides & Resources

Helpful guides from The Ultimate Homestead to improve your garden in Cowlitz County.

Frequently Asked Questions

What planting zone is Cowlitz County, WA?

Cowlitz County is in USDA Hardiness Zone 8b. This zone classification determines which perennial plants survive winter and sets the baseline for frost timing across the county.

When is the last frost in Cowlitz County, WA?

Based on 31 years of NOAA weather station data, the median last spring frost in Cowlitz County falls around April 15. In 8 out of 10 years, last frost lands between March 24 and May 7 — a 43-day window of variability. Use May 7 as your conservative safe-to-plant date for frost-sensitive crops.

When is the first fall frost in Cowlitz County, WA?

The median first fall frost in Cowlitz County arrives around October 29. In cold years it can arrive as early as October 9; in mild years as late as November 24. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.

How long is the growing season in Cowlitz County?

Cowlitz County has a frost-free growing season of approximately 197 days. This is enough time for most warm-season crops including tomatoes, peppers, and squash with proper timing. Climate records show the growing season is trending shorter by about 4.1 days per decade.

What is the soil like in Cowlitz County for gardening?

Cowlitz County has predominantly Silt Loam soil with a pH range of 5.7–6.5 and Moderately Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.

What is grown commercially in Cowlitz County?

Cowlitz County has commercial agriculture that includes Wheat, Hay, Apples, Potatoes, Cattle. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.

Is Cowlitz County a good location for home gardening?

Cowlitz County scores 63/100 (Good) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. Conditions here are moderate — most common crops grow well with standard timing and care.

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A 22-page printable planner built for Cowlitz County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA GHCN-D daily station data (1994–2024) from 3 weather stations in or near Cowlitz County (31 years of records). Frost dates represent 50% probability averages; local conditions vary by elevation and microclimate. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.