Whatcom County, WA — Planting Guide
Whatcom County is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 29, giving you a growing season of approximately 206 days.
At an elevation of 386 ft, Whatcom County receives approximately 49 in of rainfall annually. Summer highs average 85°F with winter lows around 34°F. The predominant soil type is Silt Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 52 days year to year — ranging from March 14 in warm years to May 6 in cold years. The growing season is trending longer by about 3.44 days per decade. Whatcom County scores 58/100 (Moderate) on the Microclimate Index.
🌡️ Zone
7b (5°F to 10°F min)
❄️ Last Frost
April 6
🍂 First Frost
October 29
📅 Growing Season
206 days
⛰️ Elevation
386 ft
🌧️ Annual Rainfall
49 in
Monthly Watering Calendar
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 6.1 in | 17 days | — | None |
| Feb | 6.2 in | 14 days | — | None |
| Mar | 4.3 in | 17 days | — | Low |
| Apr | 3.8 in | 11 days | 0.5 in | Low |
| May | 3.1 in | 9 days | 1.2 in | Moderate |
| Jun | 2.1 in | 7 days | 2.2 in | High |
| Jul | 0.7 in | 2 days | 3.6 in | Critical |
| Aug | 0.9 in | 3 days | 3.4 in | Critical |
| Sep | 2 in | 5 days | 2.3 in | High |
| Oct | 4.5 in | 10 days | — | Low |
| Nov | 7.1 in | 17 days | — | None |
| Dec | 8.2 in | 16 days | — | None |
Annual total: 49 in. Gardens typically need ~1 inch of water per week during the growing season. Months marked "None" for extra water are outside the active growing season for your zone — most gardens are dormant and don't need irrigation during those months.
Whatcom County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
Drainage
Well Drained
Frost Risk Probability
Based on 31 years of NOAA weather station data from 3 stations
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 6 | Nov 21 | 199 days |
| Cautious | Apr 16 | Nov 8 | 206 days |
| Average year | Apr 6 | Oct 29 | 206 days |
| Optimistic | Mar 25 | Oct 20 | 209 days |
| Aggressive (risky) | Mar 14 | Oct 8 | 208 days |
Not very — frost dates can vary by ±52 days year-to-year. Use the "Conservative" row in the table below, and keep row covers handy for surprise late frosts.
Yes — growing seasons are getting longer here (about 3.4 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.
Gardening Difficulty Score
Whatcom County presents some gardening challenges. Choose adapted varieties and plan around frost dates.
Local Gardening Help in Whatcom 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 Whatcom County's climate and soil.
County Extension Office
Whatcom 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.
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.
Services Available in Whatcom County
Finding local nurseries & garden centers in Whatcom County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Whatcom 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 Whatcom County WA" or "garden center Whatcom 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 Whatcom County WA" or check your extension office and local parks department. Facebook groups like "Whatcom 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
Sunlight & Day Length
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Longest Day
15.9 hours
Summer solstice daylight
Shortest Day
8.1 hours
Winter solstice daylight
Peak Sun Hours
11.1 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.
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
| Month | Daylight Hours | Peak Sun Hours | Day Length |
|---|---|---|---|
| January | 8.5 hr | 2 hr | Short day |
| February | 9.9 hr | 2.9 hr | Short day |
| March | 11.6 hr | 4.3 hr | Short day |
| April | 13.5 hr | 5.6 hr | Neutral |
| May | 15.1 hr | 7.2 hr | Long day |
| June | 15.9 hr | 9 hr | Long day |
| July | 15.6 hr | 11.1 hr | Long day |
| August | 14.2 hr | 9.2 hr | Long day |
| September | 12.3 hr | 7.4 hr | Neutral |
| October | 10.5 hr | 3.9 hr | Short day |
| November | 8.9 hr | 2.3 hr | Short day |
| December | 8.1 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 Calendar
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
Plant Warm Crops When
Soil reaches 60°F+
Soil warm enough from May through Oct.
Best Month to Compost
May
Microbial activity peaks when soil is warm.
Active Composting
8 months
Nearly year-round composting.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 35°F | 43°F | ❄️ Dormant | ~36 weeks |
| Feb | 39°F | 42°F | ❄️ Dormant | ~36 weeks |
| Mar | 43°F | 48°F | 🐢 Slow | ~24 weeks |
| Apr | 56°F | 54°F | ♻️ Active | ~14 weeks |
| May | 68°F | 63°F | 🔥 Peak | ~8 weeks |
| Jun | 77°F | 72°F | 🔥 Peak | ~8 weeks |
| Jul | 82°F | 77°F | 🔥 Peak | ~8 weeks |
| Aug | 84°F | 81°F | 🔥 Peak | ~8 weeks |
| Sep | 79°F | 79°F | 🔥 Peak | ~8 weeks |
| Oct | 68°F | 69°F | 🔥 Peak | ~8 weeks |
| Nov | 53°F | 60°F | ♻️ Active | ~14 weeks |
| Dec | 43°F | 49°F | 🐢 Slow | ~24 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Whatcom County
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Insect Pest Pressure
Moderate — common pests appear but manageable with monitoring.
Disease Risk
High fungal/bacterial risk. Space plants for airflow, water at soil level.
Seasonal Risk
View 6 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | High | Mar, Apr, May, Jun, Jul, Aug, Sep, Oct |
| Japanese beetles | Moderate | Jun, Jul, Aug |
| Squash vine borers | Moderate | May, Jun, Jul |
| Stink bugs | High | May, Jun, Jul, Aug, Sep |
| Whiteflies | Moderate | Jun, Jul, Aug, Sep |
| Spider mites | Moderate | Jul, Aug |
Organic pest management tips
- Use row covers on susceptible crops during peak pest months
- Apply neem oil preventatively every 7-14 days during active pest season
- Interplant with strong-scented herbs (basil, marigold) to confuse pests
- Hand-pick larger pests (beetles, caterpillars) in early morning when they're sluggish
- Practice crop rotation — never plant the same family in the same spot within 3 years
- Watch for powdery mildew, downy mildew, blight — common in your climate
Cover Crops for Whatcom County
Cover crops protect bare soil, fix nitrogen, suppress weeds, and improve soil structure — with county-specific planting dates.
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 23 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Crimson clover | Aug 24 | Mar 16 | ✓ Yes | Fixes nitrogen, attracts pollinators in spring |
| Daikon radish | Sep 7 | Mar 23 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Aug 10 | Mar 23 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 23 | Mar 23 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 31 | Mar 23 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Aug 3 | Mar 16 | — | Erosion control, weed suppression, good biomass |
Spring Cover Crops (4 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | Apr 17 | Aug 27 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Cowpeas (southern peas) | Apr 18 | Aug 27 | ✓ Yes | Excellent nitrogen fixer for warm climates, edible |
| Sorghum-sudan grass | Apr 15 | Aug 27 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Mar 12 | 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 | Apr 27 | Oct 1 | — | Deep roots break compaction, attract pollinators and beneficial insects |
Wind & Microclimate
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 11 mph Summer: 9 mph
Fall: 11 mph Winter: 12 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
4.6/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
Moderate
Some terrain variation (865 ft range). Garden on slopes or higher ground if possible to avoid late-season frost pockets.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
24,421 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, Feb, 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 49.0 inches of rain per year
- A 1,000 sq ft roof can collect roughly 24,421 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 Whatcom County
Soil Type
Silt Loam
Soil pH 5.2–6.4 · Well Drained drainage
Native soil is well-suited to most vegetables and herbs with regular compost additions.
Watering Needs
Drought stress: 3.5/10
Low-to-moderate drought stress. Plan to water 1–2 times per week during peak summer. (49 in. annual rainfall)
Season Tips
206-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.
Free Garden Planner
Plan your entire garden season — organize planting dates, track what you're growing, and know exactly when to start seeds, transplant, and harvest.
Recommended for Your Garden
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Get instant, accurate soil pH readings to fine-tune your amendments.
Boost soil fertility and structure with rich, well-aged organic compost.
🥬 Vegetables to Grow in Whatcom County
113 vegetables that grow well in Zone 7b with planting dates for Whatcom County.
Show all 113 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 9 | Apr 13 | Apr 20 | Jul 13 – Aug 17 | 80–100 |
| Amaranth | Feb 16 | Apr 13 | Apr 20 | Jul 20 – Sep 7 | 90–120 |
| Artichoke | — | — | Apr 20 | Aug 24 – Nov 2 | 120–180 |
| Arugula | Mar 2 | Mar 23 | Apr 6 | May 11 – Jul 13 | 30–50 |
| Asparagus | — | — | Apr 20 | — | 730–1095 |
| Beets | — | Mar 23 | — | May 18 – Jun 15 | 50–70 |
| Belgian Endive | Mar 2 | Mar 23 | Apr 6 | Jul 27 – Sep 21 | 110–150 |
| Bitter Melon | Feb 16 | Apr 13 | Apr 20 | Jun 22 – Aug 3 | 60–90 |
| Black Beans | — | Apr 13 | — | Jul 13 – Aug 31 | 90–120 |
| Bok Choy | Mar 2 | Mar 23 | Apr 6 | May 18 – Jun 22 | 40–60 |
| Broccoli | Mar 2 | Mar 23 | Apr 6 | Jun 8 – Jul 20 | 60–90 |
| Broccoli Rabe | Mar 2 | Mar 23 | Apr 6 | May 18 – Jun 22 | 40–60 |
| Brussels Sprouts | Mar 2 | Mar 23 | Apr 6 | Jul 6 – Aug 31 | 90–130 |
| Butternut Squash | Mar 9 | Apr 13 | Apr 20 | Jul 20 – Aug 24 | 85–110 |
| Cabbage | Mar 2 | Mar 23 | Apr 6 | Jun 8 – Aug 3 | 60–100 |
| Calabash | Feb 16 | Apr 13 | Apr 20 | Jul 13 – Sep 7 | 80–120 |
| Cardoon | — | — | Apr 20 | Aug 24 – Oct 5 | 120–150 |
| Carrots | — | Mar 23 | — | May 25 – Jun 29 | 60–80 |
| Cauliflower | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Aug 3 | 55–100 |
| Celeriac | Mar 2 | Mar 23 | Apr 6 | Jul 20 – Aug 24 | 100–120 |
| Celery | Mar 2 | Mar 23 | Apr 6 | Jun 29 – Aug 24 | 80–120 |
| Celtuce | Mar 2 | Mar 23 | Apr 6 | Jun 8 – Jul 20 | 60–90 |
| Chard | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jul 20 | 50–60 |
| Chayote | Feb 16 | Apr 13 | Apr 20 | Aug 24 – Nov 2 | 120–180 |
| Chickpeas | Mar 2 | Mar 23 | Apr 6 | Jun 29 – Aug 10 | 80–110 |
| Chicory | Mar 2 | Mar 23 | Apr 6 | Jun 8 – Jul 20 | 60–85 |
| Chinese Cabbage | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jun 29 | 50–70 |
| Christmas Lima Beans | Feb 16 | Apr 13 | Apr 20 | Jul 13 – Aug 17 | 80–100 |
| Collard Greens | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Aug 3 | 55–75 |
| Corn | — | Apr 13 | — | Jun 15 – Aug 10 | 60–100 |
| Cowpeas | — | Apr 13 | — | Jun 15 – Jul 27 | 60–90 |
| Cress | Mar 2 | Mar 23 | Apr 6 | Apr 20 – May 11 | 14–21 |
| Crookneck Squash | Mar 9 | Apr 13 | Apr 20 | Jun 8 – Jul 6 | 45–60 |
| Crosne | — | Mar 23 | — | Aug 24 – Oct 26 | 150–200 |
| Cucumber | Mar 9 | Apr 13 | Apr 20 | Jun 15 – Aug 10 | 50–70 |
| Daikon | — | Mar 23 | — | May 18 – Jun 15 | 50–70 |
| Delicata Squash | Mar 9 | Apr 13 | Apr 20 | Jul 13 – Aug 17 | 80–100 |
| Edamame | — | Apr 13 | — | Jun 29 – Aug 10 | 75–100 |
| Eggplant | Feb 2 | Apr 13 | Apr 20 | Jun 29 – Aug 31 | 65–85 |
| Endive | Mar 2 | Mar 23 | Apr 6 | May 25 – Jun 29 | 45–65 |
| Escarole | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jun 29 | 50–70 |
| Fava Beans | Mar 2 | Mar 23 | Apr 6 | Jun 22 – Aug 3 | 75–100 |
| Fennel | Feb 16 | Apr 13 | Apr 20 | Jun 22 – Aug 3 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | Apr 13 | — | Jun 8 – Aug 3 | 50–65 |
| Horseradish | — | — | Apr 20 | Aug 24 – Nov 2 | 120–180 |
| Hot Peppers | Feb 2 | Apr 13 | Apr 20 | Jun 29 – Oct 5 | 70–120 |
| Hubbard Squash | Mar 9 | Apr 13 | Apr 20 | Aug 3 – Sep 7 | 100–120 |
| Jicama | Feb 16 | Apr 13 | Apr 20 | Aug 24 – Nov 2 | 120–180 |
| Kabocha | Mar 9 | Apr 13 | Apr 20 | Jul 20 – Aug 17 | 85–100 |
| Kai Lan | Mar 2 | Mar 23 | Apr 6 | May 25 – Jun 22 | 45–60 |
| Kale | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jul 27 | 50–70 |
| Kidney Beans | — | Apr 13 | — | Jul 13 – Aug 17 | 85–110 |
| Kohlrabi | Mar 2 | Mar 23 | Apr 6 | May 25 – Jun 29 | 45–65 |
| Komatsuna | Mar 2 | Mar 23 | Apr 6 | May 11 – Jun 15 | 35–50 |
| Leeks | Mar 2 | Mar 23 | Apr 6 | Jul 6 – Sep 21 | 90–150 |
| Lentils | Mar 2 | Mar 23 | Apr 6 | Jun 29 – Aug 10 | 80–110 |
| Lettuce | Mar 2 | Mar 23 | Apr 6 | May 11 – Jul 20 | 30–60 |
| Lima Beans | — | Apr 13 | — | Jun 15 – Jul 27 | 60–90 |
| Loofah | Feb 16 | Apr 13 | Apr 20 | Aug 3 – Oct 5 | 100–150 |
| Luffa | Feb 16 | Apr 13 | Apr 20 | Jul 20 – Oct 5 | 90–150 |
| Mache | Mar 2 | Mar 23 | Apr 6 | May 18 – Jun 22 | 40–60 |
| Malabar Spinach | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Jul 13 | 55–70 |
| Melon | Mar 9 | Apr 13 | Apr 20 | Jun 29 – Aug 17 | 70–100 |
| Microgreens | Mar 2 | Mar 23 | Apr 6 | Apr 13 – May 11 | 7–21 |
| Mitsuba | Mar 2 | Mar 23 | Mar 30 | May 25 – Jul 20 | 50–70 |
| Mizuna | Mar 2 | Mar 23 | Apr 6 | May 11 – Jun 8 | 30–45 |
| Mustard Greens | Mar 2 | Mar 23 | Apr 6 | May 11 – Jul 13 | 30–50 |
| Napa Cabbage | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jul 6 | 55–75 |
| New Zealand Spinach | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Jul 13 | 55–70 |
| Okra | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Aug 10 | 50–65 |
| Onion | Mar 2 | Mar 23 | Apr 6 | Jul 6 – Aug 24 | 90–120 |
| Pac Choi | Mar 2 | Mar 23 | Apr 6 | May 18 – Jun 15 | 40–55 |
| Parsnip | — | Mar 23 | — | Jul 6 – Aug 17 | 100–130 |
| Patty Pan Squash | Mar 9 | Apr 13 | Apr 20 | Jun 8 – Jul 6 | 45–60 |
| Peas | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jul 27 | 55–70 |
| Peppers | Feb 2 | Apr 13 | Apr 20 | Jun 22 – Aug 31 | 60–90 |
| Pole Beans | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Aug 10 | 55–70 |
| Potatoes | Feb 16 | Apr 13 | Apr 20 | Jun 29 – Sep 7 | 70–120 |
| Pumpkin | Mar 9 | Apr 13 | Apr 20 | Jul 20 – Sep 7 | 85–120 |
| Purslane | Mar 2 | Mar 23 | Apr 6 | May 18 – Jun 22 | 40–60 |
| Radicchio | Mar 2 | Mar 23 | Apr 6 | Jun 8 – Jul 13 | 60–80 |
| Radish | — | Mar 23 | — | Apr 20 – May 11 | 22–35 |
| Rhubarb | — | — | Apr 27 | — | 365–730 |
| Romanesco | Mar 2 | Mar 23 | Apr 6 | Jun 22 – Aug 3 | 75–100 |
| Rutabaga | — | Mar 23 | — | Jun 15 – Jul 20 | 80–100 |
| Salsify | — | Mar 23 | — | Jul 6 – Aug 17 | 100–130 |
| Savoy Cabbage | Mar 2 | Mar 23 | Apr 6 | Jun 15 – Aug 10 | 70–110 |
| Scallions | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jun 29 | 50–70 |
| Scarlet Runner Beans | Feb 16 | Apr 13 | Apr 20 | Jun 22 – Jul 27 | 60–80 |
| Shallot | Mar 2 | Mar 23 | Apr 6 | Jul 6 – Aug 24 | 90–120 |
| Shiso | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Aug 10 | 50–70 |
| Snap Peas | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Aug 10 | 55–70 |
| Snow Peas | Mar 2 | Mar 23 | Apr 6 | Jun 1 – Jul 27 | 50–65 |
| Soybeans | — | Apr 13 | — | Jul 6 – Aug 31 | 80–120 |
| Spaghetti Squash | Mar 9 | Apr 13 | Apr 20 | Jul 20 – Aug 17 | 85–100 |
| Spinach | Mar 2 | Mar 23 | Apr 6 | May 11 – Jul 13 | 35–50 |
| Squash (Summer) | Mar 9 | Apr 13 | Apr 20 | Jun 8 – Aug 10 | 45–65 |
| Squash (Winter) | Mar 9 | Apr 13 | Apr 20 | Jul 13 – Sep 7 | 80–120 |
| Sunchoke | — | — | Apr 20 | Aug 10 – Oct 5 | 110–150 |
| Sunflower | Feb 16 | Apr 13 | Apr 20 | Jun 29 – Aug 17 | 70–100 |
| Sweet Corn | — | Apr 13 | — | Jun 15 – Jul 27 | 60–90 |
| Sweet Potatoes | Feb 16 | Apr 13 | Apr 20 | Jul 20 – Sep 7 | 90–120 |
| Tatsoi | Mar 2 | Mar 23 | Apr 6 | May 11 – Jun 15 | 35–50 |
| Tomatillo | Feb 16 | Apr 13 | Apr 20 | Jun 22 – Aug 31 | 60–85 |
| Tomatoes | Feb 16 | Apr 13 | Apr 20 | Jun 22 – Aug 31 | 60–85 |
| Turnip | — | Mar 23 | — | May 4 – Jun 8 | 40–60 |
| Watercress | Mar 2 | Mar 23 | Apr 6 | May 18 – Jun 22 | 40–60 |
| Watermelon | Mar 9 | Apr 13 | Apr 20 | Jun 29 – Aug 17 | 70–100 |
| Wax Beans | — | Apr 13 | — | Jun 8 – Aug 3 | 50–65 |
| Winter Melon | Feb 16 | Apr 13 | Apr 20 | Jul 20 – Sep 7 | 90–120 |
| Yard Long Beans | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Jul 27 | 55–80 |
| Zucchini | Mar 9 | Apr 13 | Apr 20 | Jun 8 – Aug 3 | 45–60 |
🍓 Fruits to Grow in Whatcom County
31 fruits that grow well in Zone 7b with planting dates for Whatcom County.
Show all 31 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | Apr 27 | Jul 27 – Nov 9 | 90–180 |
| Aronia | — | — | Apr 27 | — | 730–1095 |
| Blackberries | — | — | Apr 27 | — | 365–730 |
| Blueberries | — | — | Apr 27 | — | 730–1095 |
| Boysenberries | — | — | Apr 27 | — | 365–730 |
| Cantaloupe | — | — | Apr 27 | Jul 6 – Aug 10 | 70–90 |
| Che Fruit | — | — | Apr 27 | — | 1095–1825 |
| Cranberries | — | — | Apr 27 | — | 730–1095 |
| Currants | — | — | Apr 27 | — | 730–1095 |
| Elderberries | — | — | Apr 27 | — | 730–1095 |
| Figs | — | — | Apr 27 | — | 730–1825 |
| Goji Berries | — | — | Apr 27 | — | 730–1095 |
| Gooseberries | — | — | Apr 27 | — | 730–1095 |
| Grapes | — | — | Apr 27 | — | 730–1095 |
| Ground Cherry | — | — | Apr 27 | Jul 6 – Aug 31 | 65–80 |
| Hardy Kiwi | — | — | Apr 27 | — | 1095–1825 |
| Haskaps | — | — | Apr 27 | — | 730–1095 |
| Honeydew | — | — | Apr 27 | Jul 20 – Aug 31 | 80–110 |
| Jostaberry | — | — | Apr 27 | — | 730–1095 |
| Kiwi | — | — | Apr 27 | — | 1095–1825 |
| Lingonberries | — | — | Apr 27 | — | 730–1095 |
| Loquat | — | — | Apr 27 | — | 730–1825 |
| Medlar | — | — | Apr 27 | — | 1095–1825 |
| Mulberries | — | — | Apr 27 | — | 730–1825 |
| Pawpaw | — | — | Apr 27 | — | 1095–2555 |
| Persimmon | — | — | Apr 27 | — | 1095–2555 |
| Pomegranate | — | — | Apr 27 | — | 730–1095 |
| Quince | — | — | Apr 27 | — | 1095–1825 |
| Raspberries | — | — | Apr 27 | — | 365–730 |
| Serviceberries | — | — | Apr 27 | — | 730–1095 |
| Strawberries | — | — | Apr 27 | Jul 27 – Dec 7 | 90–365 |
🌿 Herbs to Grow in Whatcom County
39 herbs that grow well in Zone 7b with planting dates for Whatcom County.
Show all 39 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 2 | Mar 23 | Mar 30 | — | 365–730 |
| Anise | Mar 2 | Mar 23 | Mar 30 | Jun 29 – Sep 14 | 90–120 |
| Basil | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Aug 17 | 50–75 |
| Bee Balm | — | — | Apr 13 | Jul 13 – Sep 28 | 90–120 |
| Borage | Mar 2 | Mar 23 | Mar 30 | May 25 – Jul 13 | 50–60 |
| Caraway | Mar 2 | Mar 23 | Mar 30 | — | 365–450 |
| Catnip | — | — | Apr 13 | Jun 15 – Aug 17 | 60–80 |
| Chamomile | Mar 2 | Mar 23 | Mar 30 | Jun 1 – Aug 10 | 60–90 |
| Chervil | Mar 2 | Mar 23 | Mar 30 | May 11 – Jul 13 | 40–60 |
| Chives | — | — | Apr 13 | Jun 15 – Aug 24 | 60–90 |
| Cilantro | Mar 2 | Mar 23 | Mar 30 | May 11 – Jul 13 | 40–60 |
| Comfrey | — | — | Apr 13 | Jun 15 – Aug 24 | 60–90 |
| Cumin | Mar 2 | Mar 23 | Mar 30 | Jul 13 – Sep 14 | 100–120 |
| Dill | Mar 2 | Mar 23 | Mar 30 | May 11 – Jul 13 | 40–60 |
| Echinacea | — | — | Apr 13 | Aug 17 – Nov 23 | 120–180 |
| Epazote | Feb 16 | Apr 13 | Apr 20 | Jun 8 – Aug 3 | 45–60 |
| Fennel (herb) | Mar 2 | Mar 23 | Mar 30 | Jun 1 – Aug 10 | 60–90 |
| Feverfew | — | — | Apr 13 | Jul 13 – Sep 28 | 90–120 |
| Garlic Chives | — | — | Apr 13 | Jun 15 – Aug 24 | 60–90 |
| Horehound | — | — | Apr 13 | Jun 29 – Aug 24 | 75–90 |
| Hyssop | — | — | Apr 13 | Jun 22 – Aug 24 | 70–90 |
| Lavender | — | — | Apr 13 | Jul 13 – Nov 23 | 90–200 |
| Lemon Balm | — | — | Apr 13 | Jun 15 – Aug 3 | 60–70 |
| Lemon Thyme | — | — | Apr 13 | Jun 22 – Aug 24 | 70–90 |
| Lovage | — | — | Apr 13 | Jun 22 – Aug 24 | 70–90 |
| Marjoram | — | — | Apr 13 | Jun 15 – Aug 24 | 60–90 |
| Mint | — | — | Apr 13 | Jun 15 – Aug 24 | 60–90 |
| Oregano | — | — | Apr 13 | Jun 15 – Aug 24 | 60–90 |
| Parsley | Mar 2 | Mar 23 | Mar 30 | Jun 1 – Aug 3 | 60–80 |
| Rosemary | — | — | Apr 13 | Jul 6 – Nov 23 | 80–180 |
| Rue | — | — | Apr 13 | Jun 22 – Aug 24 | 70–90 |
| Sage | — | — | Apr 13 | Jun 29 – Aug 24 | 75–90 |
| Savory | — | — | Apr 13 | Jun 8 – Aug 3 | 50–70 |
| Sorrel | Mar 2 | Mar 23 | Mar 30 | May 11 – Jul 13 | 40–60 |
| Tarragon | — | — | Apr 13 | Jun 15 – Aug 24 | 60–90 |
| Thai Basil | Feb 16 | Apr 13 | Apr 20 | Jun 15 – Aug 17 | 50–75 |
| Thyme | — | — | Apr 13 | Jun 22 – Aug 24 | 70–90 |
| Valerian | — | — | Apr 13 | Aug 17 – Nov 23 | 120–180 |
| Yarrow | — | — | Apr 13 | Jul 13 – Sep 28 | 90–120 |
Monthly Planting Guide for Whatcom County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Whatcom County.
Frequently Asked Questions
What planting zone is Whatcom County, WA?
Whatcom County is in USDA Hardiness Zone 7b. 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 Whatcom County, WA?
Based on 31 years of NOAA weather station data, the median last spring frost in Whatcom County falls around April 6. In 8 out of 10 years, last frost lands between March 14 and May 6 — a 52-day window of variability. Use May 6 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Whatcom County, WA?
The median first fall frost in Whatcom County arrives around October 29. In cold years it can arrive as early as October 8; in mild years as late as November 21. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Whatcom County?
Whatcom County has a frost-free growing season of approximately 206 days. This long season supports multiple succession plantings and warm-season crops that need extended heat, like sweet potatoes and melons. Climate records show the growing season is trending longer by about 3.44 days per decade.
What is the soil like in Whatcom County for gardening?
Whatcom County has predominantly Silt Loam soil with a pH range of 5.2–6.4 and Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Whatcom County?
Whatcom County has commercial agriculture that includes Wheat, Apples, Potatoes. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Whatcom County a good location for home gardening?
Whatcom County scores 58/100 (Moderate) 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.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Whatcom County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.
