Blog

When to Plant Basil in Grant County, WA

Basil
Grant County, Washington Zone 7a July

Your July gardening checklist

July is a pivotal month for Grant County, Washington gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 29
Avg. first frost October 10
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 15.4 hrs
  1. It's harvest week for basil

    If you can't use it all right away, check the food-preservation section of your planner.

Get ahead of August
  • First harvests: basil

Instant PDF download. No spam, unsubscribe any time.

Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Grant County, Washington is in USDA Zone 7a. 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 feet, Grant County receives approximately 17.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Basil during the growing season. With low rainfall, drip irrigation is essential for growing Basil successfully. Mulch heavily to conserve soil moisture.

Grant County, WA (Zone 7a) Moderate season
164 days
Last Spring Frost April 29
164 growing days
First Fall Frost October 10

Grant County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.8

Drainage

Well Drained

Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (37 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 25
Recommended (50%) ✓ Fits season (31 days to spare)
Start indoors: Mar 11 Transplant: May 13 🍅 Harvest: Jul 8 – Sep 9
Safe Start (90%) ✓ Fits season (35 days to spare)
Start indoors: Mar 31 Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 29

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Grant County

How your county's soil matches Basil's growing requirements.

Soil pH

Your soil pH (5.6–6.8) overlaps with Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Grant County is excellent for Basil — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (5.7%) — Basil will thrive.

How to Plant Basil

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Basil

3
successive plantings in your 164-day season

Sow every 5.7 weeks. Last sowing by Jul 27 to harvest before frost.

Basil Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 218 gal / 100 sq ft

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan 2.7" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.6" 1.5" 1.1" 💧 Light watering
May 2.6" 1.1" 1.5" 🚿 Regular watering
Jun 2.6" 0.7" 1.9" 🚿 Regular watering
Jul 2.6" 0.2" 2.4" 🚿 Regular watering
Aug 2.6" 0.4" 2.2" 🚿 Regular watering
Sep 2.6" 0.6" 2" 🚿 Regular watering
Oct 2.6" 1.7" 0.9" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Grant County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Basil Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Basil needs ~1,141 GDD — county provides 2,993 GDD Excellent fit

Basil Planting Timeline — Grant County, WA

Basil Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors May 13 May 13 – May 27
Direct Sow May 6 May 6 – May 27
Harvest July 8 Jul 8 – Sep 9

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May Transplant Outdoors Direct Sow
June
July Harvest
August Harvest
September Harvest
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Only during dry spells

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

164 days in Grant County

Growing Tips for Basil in Grant County

Direct sow Basil outdoors after April 29 in Grant County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Grant County, WA?

Grant County is in Zone 7a with an average last frost of April 29. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, WA?

Grant County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 29 and first fall frost is October 10.

🌱

Your Grant County Garden Planner — Free

A 22-page printable planner built for Grant County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Grant County, WA. Local conditions may vary. Last updated: July 2026.

Sources & credits

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