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When to Plant Nasturtium in Kittitas County, WA

Kittitas County, Washington Zone 7a June

June in Kittitas County, Washington — your action list

We've pulled the most time-sensitive tasks for Kittitas County, Washington this June and put them front and centre. Tackle them in order.

Avg. last frost May 7
Avg. first frost October 2
Soil temp (4") 67°F
Watering Critical
Pest pressure High
Daylight 15.7 hrs
  1. Time to start nasturtium inside

    Your window is short. These crops want several weeks of indoor growth before they go outside.

Looking ahead to July
  • First harvests: nasturtium

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Nasturtium (Tropaeolum majus) is a fast-growing annual with distinctive round, lily-pad leaves and bold trumpet-shaped blooms in warm oranges, reds, and yellows. Both the flowers and leaves are edible with a peppery watercress flavor. Planted near vegetables, nasturtiums act as a sacrifice trap-crop, luring aphids away from more valuable plants. They thrive in poor, dry soil — rich conditions produce lush foliage but few flowers.

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 Nasturtium during the growing season. With low rainfall, drip irrigation is essential for growing Nasturtium successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Kittitas County, WA (Zone 7a) Short season
148 days
Last Spring Frost May 7
148 growing days
First Fall Frost October 2

Kittitas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 2 Transplant: Apr 30 🌸 Bloom: Jun 25 – Oct 29
Recommended (50%) ✗ May not fit
Start indoors: Apr 9 Transplant: May 7 🌸 Bloom: Jul 2 – Nov 5
Safe Start (90%) ✗ May not fit
Start indoors: Apr 26 Transplant: May 24 🌸 Bloom: Jul 19 – Nov 22

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 Nasturtium's growing requirements.

Soil pH

Your soil pH (5.5–6.7) overlaps with Nasturtium's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — Nasturtium will thrive.

How to Plant Nasturtium

0.5"
Planting Depth
10"
Between Plants
12"
Between Rows

Succession Planting Nasturtium

3
successive plantings in your 148-day season

Sow every 6.3 weeks. Last sowing by Jul 29 to harvest before frost.

Nasturtium Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Nasturtium

Nasturtium needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Nasturtium 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 2.2" 1.2" 1" 💧 Light watering
Jun 2.2" 0.8" 1.4" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.4" 1.8" 🚿 Regular watering
Sep 2.2" 0.8" 1.4" 🚿 Regular watering
Oct 2.2" 1.7" 0.5" 💧 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.

Nasturtium 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.

Nasturtium needs ~1,050 GDD — county provides 2,590 GDD Excellent fit

Nasturtium Planting Timeline — Kittitas County, WA

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors May 7 May 7 – May 21
Direct Sow May 7 May 7 – May 28
Bloom July 2 Jul 2 – Nov 5

Plant 0.5" deep · 10" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

55–65 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

148 days in Kittitas County

Growing Tips for Nasturtium in Kittitas County

Direct sow Nasturtium outdoors after May 07 in Kittitas County when soil has warmed and frost danger has passed.

Kittitas County receives only 19" of rain annually. Nasturtium needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct-sow large seeds 1/2 inch deep after last frost; soak seeds overnight to speed germination (7-10 days). Nasturtiums dislike root disturbance so direct sowing is strongly preferred. Avoid fertilizing — poor soil brings the best bloom. Trailing types can cover banks and climb trellises; dwarf types suit containers. In hot climates (zones 9+) plant in fall for winter/spring bloom as plants struggle in peak summer heat.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Nasturtium in Kittitas County, WA?

Kittitas County is in Zone 7a with an average last frost of May 7. Plan your Nasturtium 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 22-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.

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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: June 2026.

Sources & credits

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