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When to plant Nasturtium in Idaho County County,

Idaho County County sits in cold Zone 6b. Plant Nasturtium May 29–June 19 for the single annual harvest; the September 20 first frost closes the window.

When to Plant Nasturtium in Idaho County, ID

Idaho County, Idaho Zone 6b June

Your June gardening checklist

A quick June briefing for Idaho County, Idaho gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 29
Avg. first frost September 20
Soil temp (4") 49°F
Watering High
Pest pressure High
Daylight 15.5 hrs
  1. Fire up the seed-starting tray: nasturtium

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

Before July arrives, get these ready
  • 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.

Idaho County, Idaho is in USDA Zone 6b. The average last spring frost is May 29 and the first fall frost is September 20, giving you a growing season of approximately 114 days.

At an elevation of 6,736 feet, Idaho County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Nasturtium to ensure they mature before fall.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Idaho County, ID (Zone 6b) Short season
114 days
Last Spring Frost May 29
114 growing days
First Fall Frost September 20
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Idaho County Soil Profile

Soil Type

Loam

Soil pH

6.3-7.8

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 20 Transplant: May 18 🌸 Bloom: Jul 13 – Nov 9
Recommended (50%) ✗ May not fit
Start indoors: May 1 Transplant: May 29 🌸 Bloom: Jul 24 – Nov 20
Safe Start (90%) ✗ May not fit
Start indoors: May 27 Transplant: Jun 24 🌸 Bloom: Aug 19 – Dec 16

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 Idaho County

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

Soil pH

Your soil pH (6.3–7.8) is within Nasturtium's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Nasturtium.

How to Plant Nasturtium

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

Succession Planting Nasturtium

2
successive plantings in your 114-day season

Sow every 6.3 weeks. Last sowing by Jul 17 to harvest before frost.

Nasturtium Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 1.5" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.4" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 2.2" 3.1" 0" ✅ Rainfall sufficient
Jun 2.2" 1.8" 0.4" 💧 Light watering
Jul 2.2" 1.8" 0.4" 💧 Light watering
Aug 2.2" 2.6" 0" ✅ Rainfall sufficient
Sep 2.2" 1.9" 0.3" 💧 Light watering
Oct 2.3" 0" ❄️ Dormant
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Idaho 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 ~780 GDD — county provides 1,482 GDD Excellent fit

Nasturtium Planting Timeline — Idaho County, ID

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors May 1 May 1 – May 15
Transplant Outdoors May 29 May 29 – Jun 12
Direct Sow May 29 May 29 – Jun 19
Bloom July 24 Jul 24 – Nov 20

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6b

📆 Growing Season

114 days in Idaho County

Growing Tips for Nasturtium in Idaho County

Direct sow Nasturtium outdoors after May 29 in Idaho County when soil has warmed and frost danger has passed.

Idaho County receives only 24" 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 Idaho County, ID?

Idaho County is in Zone 6b with an average last frost of May 29. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Idaho County, ID?

Idaho County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 29 and first fall frost is September 20.

When should I plant Nasturtium in Idaho County County, ?

In Idaho County County, , plant Nasturtium after the last frost (around May 29) and before the first frost (around September 20). Best results when soil holds above 50°F.

What growing zone is Idaho County County, for Nasturtium?

Idaho County County sits in USDA Zone 6b. Nasturtium grows reliably in zones 2a through 11b, so it's a good fit here.

Can Nasturtium grow in Idaho County County's climate?

Yes — Nasturtium grows well in Idaho County County's temperate climate. Idaho County County averages a 114-day frost-free season, with last frost around May 29 and first frost around September 20.

🌱

Your Idaho County Garden Planner — Free

A 22-page printable planner built for Idaho 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.

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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 Idaho County, ID. 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.