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When to Plant Basil in Kittitas County, WA

Kittitas County, Washington Zone 7a May

Your May game plan for Kittitas County, Washington

Your garden in Kittitas County, Washington is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 7
Avg. first frost October 2
Soil temp (4") 58°F
Watering Critical
Pest pressure Low
Daylight 14.9 hrs
  1. Set out basil seedlings

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Plant basil from seed, right in the garden

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

June will be here before you know it — start on
  • Starting indoors: basil

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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.

Kittitas County, Washington is in USDA Zone 7a. The average last spring frost is May 7 and the first fall frost is October 2, giving you a growing season of approximately 148 days.

At an elevation of 2,468 feet, Kittitas County receives approximately 18.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°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.

Kittitas County, WA (Zone 7a) Short season
148 days
Last Spring Frost May 7
148 growing days
First Fall Frost October 2
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Kittitas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (17 days to spare)
Start indoors: Mar 12 Transplant: May 14 🍅 Harvest: Jul 9 – Sep 10
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 19 Transplant: May 21 🍅 Harvest: Jul 16 – Sep 17
Safe Start (90%) ✓ Fits season (17 days to spare)
Start indoors: Apr 5 Transplant: Jun 7 🍅 Harvest: Aug 2 – Oct 4

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 Kittitas County

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

Soil pH

Your soil pH (5.5–6.7) overlaps with Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — 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 148-day season

Sow every 5.7 weeks. Last sowing by Jul 19 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 101 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 2.9" 0" ❄️ Dormant
Feb 2" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 2.6" 1.2" 1.4" 🚿 Regular watering
Jun 2.6" 0.8" 1.8" 🚿 Regular watering
Jul 2.6" 0.3" 2.3" 🚿 Regular watering
Aug 2.6" 0.4" 2.2" 🚿 Regular watering
Sep 2.6" 0.8" 1.8" 🚿 Regular watering
Oct 2.6" 1.7" 0.9" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Kittitas 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 ~1,094 GDD — county provides 2,590 GDD Excellent fit

Basil Planting Timeline — Kittitas County, WA

Basil Planting Calendar

Activity When Date Range
Start Indoors March 19 Mar 19 – Apr 2
Transplant Outdoors May 21 May 21 – Jun 4
Direct Sow May 14 May 14 – Jun 4
Harvest July 16 Jul 16 – Sep 17

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

Month-by-Month Timeline

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

148 days in Kittitas County

Growing Tips for Basil in Kittitas County

Direct sow Basil outdoors after May 07 in Kittitas 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 Kittitas County, WA?

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

What planting zone is Kittitas County, WA?

Kittitas County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 7 and first fall frost is October 2.

🌱

Your Kittitas County Garden Planner — Free

A 24-page printable planner built for Kittitas 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 Kittitas County, WA. Local conditions may vary. Last updated: May 2026.

Sources & credits

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