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When to plant Nasturtium in Scott County County,

The best window to plant Nasturtium in Scott County County, is April 22–May 13, when soil warms to 50°F. Last frost typically hits April 15; first frost October 17.

When to Plant Nasturtium in Scott County, IA

Scott County, Iowa Zone 5b June

This month in Scott County, Iowa

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Scott County, Iowa.

Avg. last frost April 15
Avg. first frost October 17
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 15 hrs
  1. Collect nasturtium at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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.

Scott County, Iowa is in USDA Zone 5b. The average last spring frost is April 15 and the first fall frost is October 17, giving you a growing season of approximately 185 days.

At an elevation of 678 feet, Scott County receives approximately 37.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°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
Scott County, IA (Zone 5b) Moderate season
185 days
Last Spring Frost April 15
185 growing days
First Fall Frost October 17

Scott County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.7

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✓ Fits season (16 days to spare)
Start indoors: Mar 13 Transplant: Apr 17 🌸 Bloom: Jun 12 – Sep 25
Recommended (50%) ✓ Fits season (17 days to spare)
Start indoors: Mar 18 Transplant: Apr 22 🌸 Bloom: Jun 17 – Sep 30
Safe Start (90%) ✓ Fits season (16 days to spare)
Start indoors: Apr 5 Transplant: May 10 🌸 Bloom: Jul 5 – Oct 18

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 Scott County

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

Soil pH

Your soil pH (5.8–6.7) overlaps with Nasturtium's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — 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 185-day season

Sow every 6.3 weeks. Last sowing by Aug 13 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 1.4" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.8" 0" ✅ Rainfall sufficient
Jul 2.2" 4.6" 0" ✅ Rainfall sufficient
Aug 2.2" 3.9" 0" ✅ Rainfall sufficient
Sep 2.2" 3" 0" ✅ Rainfall sufficient
Oct 2.2" 3" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Scott 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 ~735 GDD — county provides 2,266 GDD Excellent fit

Nasturtium Planting Timeline — Scott County, IA

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors April 22 Apr 22 – May 6
Direct Sow April 22 Apr 22 – May 13
Bloom June 17 Jun 17 – Sep 30

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Bloom
July Bloom
August Bloom
September Bloom
October
November
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 5b

📆 Growing Season

185 days in Scott County

Growing Tips for Nasturtium in Scott County

Direct sow Nasturtium outdoors after April 15 in Scott County when soil has warmed and frost danger has passed.

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 Scott County, IA?

Scott County is in Zone 5b with an average last frost of April 15. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Scott County, IA?

Scott County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 15 and first fall frost is October 17.

When should I plant Nasturtium in Scott County County, ?

In Scott County County, , plant Nasturtium after the last frost (around April 15) and before the first frost (around October 17). Best results when soil holds above 50°F.

What growing zone is Scott County County, for Nasturtium?

Scott County County sits in USDA Zone 5b. Nasturtium grows reliably in zones 2a through 11b, so it's a good fit here.

Can Nasturtium grow in Scott County County's climate?

Yes — Nasturtium grows well in Scott County County's temperate climate. Scott County County averages a 185-day frost-free season, with last frost around April 15 and first frost around October 17.

🌱

Your Scott County Garden Planner — Free

A 22-page printable planner built for Scott County (Zone 5b). 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 Scott County, IA. Local conditions may vary. Last updated: June 2026.

Sources & credits

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