Grant County, WA — Planting Guide
Grant County is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 10, giving you a growing season of approximately 164 days.
At an elevation of 3,122 ft, Grant County receives approximately 17.6 in of rainfall annually. Summer highs average 91°F with winter lows around 25°F. The predominant soil type is Silt Loam.
Based on 31 years of NOAA climate station data, the last frost date here varies by 48 days year to year — ranging from April 1 in warm years to May 19 in cold years. The growing season is trending longer by about 1.78 days per decade. Grant County scores 50/100 (Moderate) on the Microclimate Index.
🌡️ Zone
6b (-5°F to 0°F min)
❄️ Last Frost
April 29
🍂 First Frost
October 10
📅 Growing Season
164 days
⛰️ Elevation
3,122 ft
🌧️ Annual Rainfall
17.6 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 | 2.7 in | 20 days | — | None |
| Feb | 1.8 in | 17 days | — | None |
| Mar | 2 in | 14 days | 2.3 in | High |
| Apr | 1.5 in | 13 days | 2.8 in | High |
| May | 1.1 in | 10 days | 3.2 in | Critical |
| Jun | 0.7 in | 7 days | 3.6 in | Critical |
| Jul | 0.2 in | 3 days | 4.1 in | Critical |
| Aug | 0.4 in | 2 days | 3.9 in | Critical |
| Sep | 0.6 in | 4 days | 3.7 in | Critical |
| Oct | 1.7 in | 11 days | 2.6 in | High |
| Nov | 2.5 in | 17 days | — | None |
| Dec | 2.5 in | 20 days | — | None |
Annual total: 17.7 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.
Grant County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.8
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 19 | Nov 3 | 168 days |
| Cautious | May 9 | Oct 24 | 168 days |
| Average year | Apr 29 | Oct 10 | 164 days |
| Optimistic | Apr 14 | Oct 1 | 170 days |
| Aggressive (risky) | Apr 1 | Sep 21 | 173 days |
Not very — frost dates can vary by ±48 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 1.8 days per decade). Spring is arriving earlier than it used to. Good news for gardeners.
Gardening Difficulty Score
Grant County presents some gardening challenges. Choose adapted varieties and plan around frost dates.
Local Gardening Help in Grant 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 Grant County's climate and soil.
County Extension Office
Grant 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 Grant County
Finding local nurseries & garden centers in Grant County
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Grant 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 Grant County WA" or "garden center Grant 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 Grant County WA" or check your extension office and local parks department. Facebook groups like "Grant 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
15.7 hours
Summer solstice daylight
Shortest Day
8.3 hours
Winter solstice daylight
Peak Sun Hours
11.3 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 | 8.7 hr | 2.2 hr | Short day |
| February | 10 hr | 3.1 hr | Short day |
| March | 11.6 hr | 4 hr | Short day |
| April | 13.4 hr | 5.9 hr | Neutral |
| May | 14.9 hr | 7.8 hr | Long day |
| June | 15.7 hr | 8.3 hr | Long day |
| July | 15.4 hr | 11.3 hr | Long day |
| August | 14 hr | 9.6 hr | Long day |
| September | 12.3 hr | 7.3 hr | Neutral |
| October | 10.6 hr | 4 hr | Short day |
| November | 9.1 hr | 2.3 hr | Short day |
| December | 8.3 hr | 1.9 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 Jun through Sep.
Best Month to Compost
Jun
Microbial activity peaks when soil is warm.
Active Composting
6 months
Solid season. Piles go dormant in winter.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 24°F | 32°F | ❄️ Dormant | ~36 weeks |
| Feb | 22°F | 31°F | ❄️ Dormant | ~36 weeks |
| Mar | 33°F | 33°F | ❄️ Dormant | ~36 weeks |
| Apr | 45°F | 42°F | 🐢 Slow | ~24 weeks |
| May | 56°F | 52°F | ♻️ Active | ~14 weeks |
| Jun | 65°F | 61°F | 🔥 Peak | ~8 weeks |
| Jul | 71°F | 68°F | 🔥 Peak | ~8 weeks |
| Aug | 76°F | 69°F | 🔥 Peak | ~8 weeks |
| Sep | 66°F | 65°F | 🔥 Peak | ~8 weeks |
| Oct | 57°F | 57°F | ♻️ Active | ~14 weeks |
| Nov | 40°F | 47°F | ❄️ Dormant | ~36 weeks |
| Dec | 28°F | 38°F | ❄️ Dormant | ~36 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Grant 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
Low disease risk — dry conditions reduce fungal problems.
Seasonal Risk
View 6 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Moderate | Apr, May, Jun, Jul, Aug, Sep |
| Japanese beetles | High | Jun, Jul, Aug |
| Squash vine borers | Moderate | Jun, Jul |
| Tomato hornworms | Moderate | Jun, Jul, Aug |
| Cucumber beetles | Moderate | May, Jun, Jul |
| Stink bugs | Moderate | Jun, Jul, Aug, Sep |
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
Cover Crops for Grant 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 9 | Apr 8 | ✓ Yes | Fixes nitrogen, good for heavy clay soils |
| Crimson clover | Aug 18 | Apr 15 | ✓ Yes | Fixes nitrogen, attracts pollinators in spring |
| Daikon radish | Sep 1 | Apr 15 | — | Deep taproot breaks compaction, excellent for clay soils |
| Hairy vetch | Jul 30 | Apr 8 | ✓ Yes | Excellent nitrogen fixer, good for depleted soils |
| Oats | Sep 4 | Apr 8 | — | Quick biomass, winterkills in cold zones — no spring tillage needed |
| Winter rye | Jul 4 | Apr 8 | — | Suppresses weeds, prevents erosion, breaks up compacted soil |
| Winter wheat | Jul 20 | Apr 8 | — | Erosion control, weed suppression, good biomass |
Spring Cover Crops (3 options) — Build soil before the main growing season
| Crop | Plant By | Terminate | N-Fixing | Soil Benefit |
|---|---|---|---|---|
| Buckwheat | May 5 | Aug 8 | — | Rapid growth, attracts pollinators, suppresses weeds |
| Sorghum-sudan grass | May 8 | Aug 15 | — | Massive biomass, breaks compaction, suppresses nematodes |
| White clover | Apr 4 | Aug 15 | ✓ 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 24 | Sep 19 | — | 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: 13 mph Summer: 10 mph
Fall: 9 mph Winter: 14 mph
Prevailing wind: SW. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
7.4/10
Strongly recommended — a windbreak (fence, hedge, or row of tall crops like corn or sunflowers) will significantly improve garden yields.
Frost Pocket Risk
Low
Relatively flat terrain (348 ft range). Frost pocket risk is minimal — garden placement is flexible.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
8,821 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
8 rain barrels (55 gal each)
For a typical 500 sq ft garden. Serious collectors: consider a 2,250 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
Jun, Jul, Aug, Sep
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 17.7 inches of rain per year
- A 1,000 sq ft roof can collect roughly 8,821 gallons annually
- Rainwater harvesting is fully legal in your state
- In your dry climate, every drop counts — consider a larger cistern system
- Position collection tanks in shade to reduce evaporation and algae growth
Soil & Growing Conditions in Grant County
Soil Type
Silt Loam
Soil pH 5.6–6.8 · Moderately 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. (17.6 in. annual rainfall)
Season Tips
164-day frost-free season
Start warm-season crops indoors and focus on short-season varieties. Cold frames extend your season by 3–4 weeks in fall.
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 Grant County
108 vegetables that grow well in Zone 6b with planting dates for Grant County.
Show all 108 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Acorn Squash | Mar 25 | May 6 | May 13 | Aug 5 – Sep 9 | 80–100 |
| Amaranth | Mar 4 | May 6 | May 13 | Aug 12 – Sep 30 | 90–120 |
| Arugula | Mar 25 | Apr 15 | Apr 29 | Jun 3 – Aug 5 | 30–50 |
| Asparagus | — | — | May 13 | — | 730–1095 |
| Beets | — | Apr 15 | — | Jun 10 – Jul 8 | 50–70 |
| Belgian Endive | Mar 25 | Apr 15 | Apr 29 | Aug 19 – Oct 14 | 110–150 |
| Bitter Melon | Mar 4 | May 6 | May 13 | Jul 15 – Aug 26 | 60–90 |
| Black Beans | — | May 6 | — | Aug 5 – Sep 23 | 90–120 |
| Bok Choy | Mar 25 | Apr 15 | Apr 29 | Jun 10 – Jul 15 | 40–60 |
| Broccoli | Mar 25 | Apr 15 | Apr 29 | Jul 1 – Aug 12 | 60–90 |
| Broccoli Rabe | Mar 25 | Apr 15 | Apr 29 | Jun 10 – Jul 15 | 40–60 |
| Brussels Sprouts | Mar 25 | Apr 15 | Apr 29 | Jul 29 – Sep 23 | 90–130 |
| Butternut Squash | Mar 25 | May 6 | May 13 | Aug 12 – Sep 16 | 85–110 |
| Cabbage | Mar 25 | Apr 15 | Apr 29 | Jul 1 – Aug 26 | 60–100 |
| Calabash | Mar 4 | May 6 | May 13 | Aug 5 – Sep 30 | 80–120 |
| Carrots | — | Apr 15 | — | Jun 17 – Jul 22 | 60–80 |
| Cauliflower | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Aug 26 | 55–100 |
| Celeriac | Mar 25 | Apr 15 | Apr 29 | Aug 12 – Sep 16 | 100–120 |
| Celery | Mar 25 | Apr 15 | Apr 29 | Jul 22 – Sep 16 | 80–120 |
| Celtuce | Mar 25 | Apr 15 | Apr 29 | Jul 1 – Aug 12 | 60–90 |
| Chard | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Aug 12 | 50–60 |
| Chickpeas | Mar 25 | Apr 15 | Apr 29 | Jul 22 – Sep 2 | 80–110 |
| Chicory | Mar 25 | Apr 15 | Apr 29 | Jul 1 – Aug 12 | 60–85 |
| Chinese Cabbage | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Jul 22 | 50–70 |
| Christmas Lima Beans | Mar 4 | May 6 | May 13 | Aug 5 – Sep 9 | 80–100 |
| Collard Greens | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Aug 26 | 55–75 |
| Corn | — | May 6 | — | Jul 8 – Sep 2 | 60–100 |
| Cowpeas | — | May 6 | — | Jul 8 – Aug 19 | 60–90 |
| Cress | Mar 25 | Apr 15 | Apr 29 | May 13 – Jun 3 | 14–21 |
| Crookneck Squash | Mar 25 | May 6 | May 13 | Jul 1 – Jul 29 | 45–60 |
| Crosne | — | Apr 15 | — | Sep 16 – Oct 28 | 150–200 |
| Cucumber | Mar 25 | May 6 | May 13 | Jul 8 – Sep 2 | 50–70 |
| Daikon | — | Apr 15 | — | Jun 10 – Jul 8 | 50–70 |
| Delicata Squash | Mar 25 | May 6 | May 13 | Aug 5 – Sep 9 | 80–100 |
| Edamame | — | May 6 | — | Jul 22 – Sep 2 | 75–100 |
| Eggplant | Feb 18 | May 6 | May 13 | Jul 22 – Sep 23 | 65–85 |
| Endive | Mar 25 | Apr 15 | Apr 29 | Jun 17 – Jul 22 | 45–65 |
| Escarole | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Jul 22 | 50–70 |
| Fava Beans | Mar 25 | Apr 15 | Apr 29 | Jul 15 – Aug 26 | 75–100 |
| Fennel | Mar 4 | May 6 | May 13 | Jul 15 – Aug 26 | 60–90 |
| Garlic | — | — | — | — | 90–240 |
| Green Beans | — | May 6 | — | Jul 1 – Aug 26 | 50–65 |
| Horseradish | — | — | May 13 | Sep 16 – Nov 25 | 120–180 |
| Hot Peppers | Feb 18 | May 6 | May 13 | Jul 22 – Oct 28 | 70–120 |
| Hubbard Squash | Mar 25 | May 6 | May 13 | Aug 26 – Sep 30 | 100–120 |
| Kabocha | Mar 25 | May 6 | May 13 | Aug 12 – Sep 9 | 85–100 |
| Kai Lan | Mar 25 | Apr 15 | Apr 29 | Jun 17 – Jul 15 | 45–60 |
| Kale | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Aug 19 | 50–70 |
| Kidney Beans | — | May 6 | — | Aug 5 – Sep 9 | 85–110 |
| Kohlrabi | Mar 25 | Apr 15 | Apr 29 | Jun 17 – Jul 22 | 45–65 |
| Komatsuna | Mar 25 | Apr 15 | Apr 29 | Jun 3 – Jul 8 | 35–50 |
| Leeks | Mar 25 | Apr 15 | Apr 29 | Jul 29 – Oct 14 | 90–150 |
| Lentils | Mar 25 | Apr 15 | Apr 29 | Jul 22 – Sep 2 | 80–110 |
| Lettuce | Mar 25 | Apr 15 | Apr 29 | Jun 3 – Aug 12 | 30–60 |
| Lima Beans | — | May 6 | — | Jul 8 – Aug 19 | 60–90 |
| Loofah | Mar 4 | May 6 | May 13 | Aug 26 – Oct 28 | 100–150 |
| Luffa | Mar 4 | May 6 | May 13 | Aug 12 – Oct 28 | 90–150 |
| Mache | Mar 25 | Apr 15 | Apr 29 | Jun 10 – Jul 15 | 40–60 |
| Melon | Mar 25 | May 6 | May 13 | Jul 22 – Sep 9 | 70–100 |
| Microgreens | Mar 25 | Apr 15 | Apr 29 | May 6 – Jun 3 | 7–21 |
| Mitsuba | Mar 25 | Apr 15 | Apr 22 | Jun 17 – Aug 12 | 50–70 |
| Mizuna | Mar 25 | Apr 15 | Apr 29 | Jun 3 – Jul 1 | 30–45 |
| Mustard Greens | Mar 25 | Apr 15 | Apr 29 | Jun 3 – Aug 5 | 30–50 |
| Napa Cabbage | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Jul 29 | 55–75 |
| New Zealand Spinach | Mar 4 | May 6 | May 13 | Jul 8 – Aug 5 | 55–70 |
| Okra | Mar 4 | May 6 | May 13 | Jul 8 – Sep 2 | 50–65 |
| Onion | Mar 25 | Apr 15 | Apr 29 | Jul 29 – Sep 16 | 90–120 |
| Pac Choi | Mar 25 | Apr 15 | Apr 29 | Jun 10 – Jul 8 | 40–55 |
| Parsnip | — | Apr 15 | — | Jul 29 – Sep 9 | 100–130 |
| Patty Pan Squash | Mar 25 | May 6 | May 13 | Jul 1 – Jul 29 | 45–60 |
| Peas | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Aug 19 | 55–70 |
| Peppers | Feb 18 | May 6 | May 13 | Jul 15 – Sep 23 | 60–90 |
| Pole Beans | Mar 4 | May 6 | May 13 | Jul 8 – Sep 2 | 55–70 |
| Potatoes | Mar 4 | May 6 | May 13 | Jul 22 – Sep 30 | 70–120 |
| Pumpkin | Mar 25 | May 6 | May 13 | Aug 12 – Sep 30 | 85–120 |
| Purslane | Mar 25 | Apr 15 | Apr 29 | Jun 10 – Jul 15 | 40–60 |
| Radicchio | Mar 25 | Apr 15 | Apr 29 | Jul 1 – Aug 5 | 60–80 |
| Radish | — | Apr 15 | — | May 13 – Jun 3 | 22–35 |
| Rhubarb | — | — | May 20 | — | 365–730 |
| Romanesco | Mar 25 | Apr 15 | Apr 29 | Jul 15 – Aug 26 | 75–100 |
| Rutabaga | — | Apr 15 | — | Jul 8 – Aug 12 | 80–100 |
| Salsify | — | Apr 15 | — | Jul 29 – Sep 9 | 100–130 |
| Savoy Cabbage | Mar 25 | Apr 15 | Apr 29 | Jul 8 – Sep 2 | 70–110 |
| Scallions | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Jul 22 | 50–70 |
| Scarlet Runner Beans | Mar 4 | May 6 | May 13 | Jul 15 – Aug 19 | 60–80 |
| Shallot | Mar 25 | Apr 15 | Apr 29 | Jul 29 – Sep 16 | 90–120 |
| Shiso | Mar 11 | May 6 | May 13 | Jul 8 – Sep 2 | 50–70 |
| Snap Peas | Mar 4 | May 6 | May 13 | Jul 8 – Sep 2 | 55–70 |
| Snow Peas | Mar 25 | Apr 15 | Apr 29 | Jun 24 – Aug 19 | 50–65 |
| Soybeans | — | May 6 | — | Jul 29 – Sep 23 | 80–120 |
| Spaghetti Squash | Mar 25 | May 6 | May 13 | Aug 12 – Sep 9 | 85–100 |
| Spinach | Mar 25 | Apr 15 | Apr 29 | Jun 3 – Aug 5 | 35–50 |
| Squash (Summer) | Mar 25 | May 6 | May 13 | Jul 1 – Sep 2 | 45–65 |
| Squash (Winter) | Mar 25 | May 6 | May 13 | Aug 5 – Sep 30 | 80–120 |
| Sunchoke | — | — | May 13 | Sep 2 – Oct 28 | 110–150 |
| Sunflower | Mar 4 | May 6 | May 13 | Jul 22 – Sep 9 | 70–100 |
| Sweet Corn | — | May 6 | — | Jul 8 – Aug 19 | 60–90 |
| Sweet Potatoes | Mar 4 | May 6 | May 13 | Aug 12 – Sep 30 | 90–120 |
| Tatsoi | Mar 25 | Apr 15 | Apr 29 | Jun 3 – Jul 8 | 35–50 |
| Tomatillo | Mar 4 | May 6 | May 13 | Jul 15 – Sep 23 | 60–85 |
| Tomatoes | Mar 4 | May 6 | May 13 | Jul 15 – Sep 23 | 60–85 |
| Turnip | — | Apr 15 | — | May 27 – Jul 1 | 40–60 |
| Watercress | Mar 25 | Apr 15 | Apr 29 | Jun 10 – Jul 15 | 40–60 |
| Watermelon | Mar 25 | May 6 | May 13 | Jul 22 – Sep 9 | 70–100 |
| Wax Beans | — | May 6 | — | Jul 1 – Aug 26 | 50–65 |
| Winter Melon | Mar 4 | May 6 | May 13 | Aug 12 – Sep 30 | 90–120 |
| Yard Long Beans | Mar 4 | May 6 | May 13 | Jul 8 – Aug 19 | 55–80 |
| Zucchini | Mar 25 | May 6 | May 13 | Jul 1 – Aug 26 | 45–60 |
🍓 Fruits to Grow in Grant County
27 fruits that grow well in Zone 6b with planting dates for Grant County.
Show all 27 fruits with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Alpine Strawberries | — | — | May 20 | Aug 19 – Dec 2 | 90–180 |
| Aronia | — | — | May 20 | — | 730–1095 |
| Blackberries | — | — | May 20 | — | 365–730 |
| Blueberries | — | — | May 20 | — | 730–1095 |
| Boysenberries | — | — | May 20 | — | 365–730 |
| Cantaloupe | — | — | May 20 | Jul 29 – Sep 2 | 70–90 |
| Che Fruit | — | — | May 20 | — | 1095–1825 |
| Cranberries | — | — | May 20 | — | 730–1095 |
| Currants | — | — | May 20 | — | 730–1095 |
| Elderberries | — | — | May 20 | — | 730–1095 |
| Goji Berries | — | — | May 20 | — | 730–1095 |
| Gooseberries | — | — | May 20 | — | 730–1095 |
| Grapes | — | — | May 20 | — | 730–1095 |
| Ground Cherry | — | — | May 20 | Jul 29 – Sep 23 | 65–80 |
| Hardy Kiwi | — | — | May 20 | — | 1095–1825 |
| Haskaps | — | — | May 20 | — | 730–1095 |
| Honeydew | — | — | May 20 | Aug 12 – Sep 23 | 80–110 |
| Jostaberry | — | — | May 20 | — | 730–1095 |
| Lingonberries | — | — | May 20 | — | 730–1095 |
| Medlar | — | — | May 20 | — | 1095–1825 |
| Mulberries | — | — | May 20 | — | 730–1825 |
| Pawpaw | — | — | May 20 | — | 1095–2555 |
| Persimmon | — | — | May 20 | — | 1095–2555 |
| Quince | — | — | May 20 | — | 1095–1825 |
| Raspberries | — | — | May 20 | — | 365–730 |
| Serviceberries | — | — | May 20 | — | 730–1095 |
| Strawberries | — | — | May 20 | Aug 19 – Dec 2 | 90–365 |
🌿 Herbs to Grow in Grant County
38 herbs that grow well in Zone 6b with planting dates for Grant County.
Show all 38 herbs with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Angelica | Mar 25 | Apr 15 | Apr 22 | — | 365–730 |
| Anise | Mar 25 | Apr 15 | Apr 22 | Jul 22 – Oct 7 | 90–120 |
| Basil | Mar 11 | May 6 | May 13 | Jul 8 – Sep 9 | 50–75 |
| Bee Balm | — | — | May 6 | Aug 5 – Oct 21 | 90–120 |
| Borage | Mar 25 | Apr 15 | Apr 22 | Jun 17 – Aug 5 | 50–60 |
| Caraway | Mar 25 | Apr 15 | Apr 22 | — | 365–450 |
| Catnip | — | — | May 6 | Jul 8 – Sep 9 | 60–80 |
| Chamomile | Mar 25 | Apr 15 | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Chervil | Mar 25 | Apr 15 | Apr 22 | Jun 3 – Aug 5 | 40–60 |
| Chives | — | — | May 6 | Jul 8 – Sep 16 | 60–90 |
| Cilantro | Mar 25 | Apr 15 | Apr 22 | Jun 3 – Aug 5 | 40–60 |
| Comfrey | — | — | May 6 | Jul 8 – Sep 16 | 60–90 |
| Cumin | Mar 25 | Apr 15 | Apr 22 | Aug 5 – Oct 7 | 100–120 |
| Dill | Mar 25 | Apr 15 | Apr 22 | Jun 3 – Aug 5 | 40–60 |
| Echinacea | — | — | May 6 | Sep 9 – Nov 18 | 120–180 |
| Epazote | Mar 11 | May 6 | May 13 | Jul 1 – Aug 26 | 45–60 |
| Fennel (herb) | Mar 25 | Apr 15 | Apr 22 | Jun 24 – Sep 2 | 60–90 |
| Feverfew | — | — | May 6 | Aug 5 – Oct 21 | 90–120 |
| Garlic Chives | — | — | May 6 | Jul 8 – Sep 16 | 60–90 |
| Horehound | — | — | May 6 | Jul 22 – Sep 16 | 75–90 |
| Hyssop | — | — | May 6 | Jul 15 – Sep 16 | 70–90 |
| Lavender | — | — | May 6 | Aug 5 – Nov 18 | 90–200 |
| Lemon Balm | — | — | May 6 | Jul 8 – Aug 26 | 60–70 |
| Lemon Thyme | — | — | May 6 | Jul 15 – Sep 16 | 70–90 |
| Lovage | — | — | May 6 | Jul 15 – Sep 16 | 70–90 |
| Marjoram | — | — | May 6 | Jul 8 – Sep 16 | 60–90 |
| Mint | — | — | May 6 | Jul 8 – Sep 16 | 60–90 |
| Oregano | — | — | May 6 | Jul 8 – Sep 16 | 60–90 |
| Parsley | Mar 25 | Apr 15 | Apr 22 | Jun 24 – Aug 26 | 60–80 |
| Rue | — | — | May 6 | Jul 15 – Sep 16 | 70–90 |
| Sage | — | — | May 6 | Jul 22 – Sep 16 | 75–90 |
| Savory | — | — | May 6 | Jul 1 – Aug 26 | 50–70 |
| Sorrel | Mar 25 | Apr 15 | Apr 22 | Jun 3 – Aug 5 | 40–60 |
| Tarragon | — | — | May 6 | Jul 8 – Sep 16 | 60–90 |
| Thai Basil | Mar 11 | May 6 | May 13 | Jul 8 – Sep 9 | 50–75 |
| Thyme | — | — | May 6 | Jul 15 – Sep 16 | 70–90 |
| Valerian | — | — | May 6 | Sep 9 – Nov 18 | 120–180 |
| Yarrow | — | — | May 6 | Aug 5 – Oct 21 | 90–120 |
Monthly Planting Guide for Grant County
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Grant County.
Frequently Asked Questions
What planting zone is Grant County, WA?
Grant County is in USDA Hardiness Zone 6b. 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 Grant County, WA?
Based on 31 years of NOAA weather station data, the median last spring frost in Grant County falls around April 29. In 8 out of 10 years, last frost lands between April 1 and May 19 — a 48-day window of variability. Use May 19 as your conservative safe-to-plant date for frost-sensitive crops.
When is the first fall frost in Grant County, WA?
The median first fall frost in Grant County arrives around October 10. In cold years it can arrive as early as September 21; in mild years as late as November 3. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
How long is the growing season in Grant County?
Grant County has a frost-free growing season of approximately 164 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 longer by about 1.78 days per decade.
What is the soil like in Grant County for gardening?
Grant County has predominantly Silt Loam soil with a pH range of 5.6–6.8 and Moderately Well Drained drainage. Most vegetables and herbs grow well with standard composting and seasonal soil amendment.
What is grown commercially in Grant County?
Grant County has commercial agriculture that includes Wheat, Hay, 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 Grant County a good location for home gardening?
Grant County scores 50/100 (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 Grant County gardeners in Zone 6b 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.
