Blog

When to Plant Nasturtium in Malheur County, OR

Malheur County, Oregon Zone 6b June

June in Malheur County, Oregon — your action list

Each item below is timed to Malheur County, Oregon's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost May 18
Avg. first frost September 29
Soil temp (4") 67°F
Watering Critical
Pest pressure High
Daylight 15.2 hrs
  1. Start nasturtium indoors

    Label every cell. You will absolutely forget which is which otherwise.

Get ahead of July
  • First harvests: nasturtium

Instant PDF download. No spam, unsubscribe any time.

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.

Malheur County, Oregon is in USDA Zone 6b. The average last spring frost is May 18 and the first fall frost is September 29, giving you a growing season of approximately 134 days.

At an elevation of 2,676 feet, Malheur County receives approximately 17.5 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
Malheur County, OR (Zone 6b) Short season
134 days
Last Spring Frost May 18
134 growing days
First Fall Frost September 29

Malheur County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.3

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 3 Transplant: May 1 🌸 Bloom: Jun 26 – Oct 23
Recommended (50%) ✗ May not fit
Start indoors: Apr 20 Transplant: May 18 🌸 Bloom: Jul 13 – Nov 9
Safe Start (90%) ✗ May not fit
Start indoors: May 15 Transplant: Jun 12 🌸 Bloom: Aug 7 – Dec 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 Malheur County

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

Soil pH

Your soil pH (5.4–6.3) is more acidic than Nasturtium prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Nasturtium.

Organic Matter

Organic matter is excellent (5.6%) — Nasturtium will thrive.

How to Plant Nasturtium

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

Succession Planting Nasturtium

2
successive plantings in your 134-day season

Sow every 6.3 weeks. Last sowing by Jul 26 to harvest before frost.

Nasturtium Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 121 gal / 100 sq ft

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 2.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 2.2" 0.9" 1.3" 🚿 Regular watering
Jun 2.2" 0.7" 1.5" 🚿 Regular watering
Jul 2.2" 0.3" 1.9" 🚿 Regular watering
Aug 2.2" 0.3" 1.9" 🚿 Regular watering
Sep 2.2" 0.8" 1.4" 🚿 Regular watering
Oct 1.4" 0" ❄️ Dormant
Nov 2.6" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Malheur 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 2,345 GDD Excellent fit

Nasturtium Planting Timeline — Malheur County, OR

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors April 20 Apr 20 – May 4
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 18 May 18 – Jun 8
Bloom July 13 Jul 13 – Nov 9

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

55–65 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

134 days in Malheur County

Growing Tips for Nasturtium in Malheur County

Direct sow Nasturtium outdoors after May 18 in Malheur County when soil has warmed and frost danger has passed.

Malheur County receives only 18" 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 Malheur County, OR?

Malheur County is in Zone 6b with an average last frost of May 18. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Malheur County, OR?

Malheur County, Oregon is in USDA Hardiness Zone 6b. The average last spring frost is May 18 and first fall frost is September 29.

🌱

Your Malheur County Garden Planner — Free

A 22-page printable planner built for Malheur County (Zone 6b). 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 Malheur County, OR. 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.