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When to plant Nasturtium in Jackson County, MN

For Nasturtium in Jackson County, the safe spring window opens around May 7 and closes around May 28. Last expected frost is April 30, first fall frost October 6, giving a 159-day growing season.

When to Plant Nasturtium in Jackson County, MN

Jackson County, Minnesota Zone 5a July

Top priorities for Jackson County, Minnesota gardeners in July

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

Avg. last frost April 30
Avg. first frost October 6
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Start harvesting nasturtium

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

Before August 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.

Jackson County, Minnesota is in USDA Zone 5a. The average last spring frost is April 30 and the first fall frost is October 6, giving you a growing season of approximately 159 days.

At an elevation of 1,042 feet, Jackson County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°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
Jackson County, MN (Zone 5a) Moderate season
159 days
Last Spring Frost April 30
159 growing days
First Fall Frost October 6

Jackson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-7

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Mar 25 Transplant: Apr 29 🌸 Bloom: Jun 24 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Apr 2 Transplant: May 7 🌸 Bloom: Jul 2 – Oct 8
Safe Start (90%) ✗ May not fit
Start indoors: Apr 16 Transplant: May 21 🌸 Bloom: Jul 16 – Oct 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 Jackson County

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

Soil pH

Your soil pH (6.1–7.0) is within Nasturtium's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — 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 159-day season

Sow every 6.3 weeks. Last sowing by Aug 02 to harvest before frost.

Nasturtium Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.6" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.2" 3.5" 0" ✅ Rainfall sufficient
May 2.2" 4.6" 0" ✅ Rainfall sufficient
Jun 2.2" 4.7" 0" ✅ Rainfall sufficient
Jul 2.2" 4.5" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 3.1" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jackson 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 ~600 GDD — county provides 1,590 GDD Excellent fit

Nasturtium Planting Timeline — Jackson County, MN

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 7 May 7 – May 21
Direct Sow May 7 May 7 – May 28
Bloom July 2 Jul 2 – Oct 8

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
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: ideal

🗺️ USDA Zone

Zone 5a

📆 Growing Season

159 days in Jackson County

Growing Tips for Nasturtium in Jackson County

Direct sow Nasturtium outdoors after April 30 in Jackson 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 Jackson County, MN?

Jackson County is in Zone 5a with an average last frost of April 30. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jackson County, MN?

Jackson County, Minnesota is in USDA Hardiness Zone 5a. The average last spring frost is April 30 and first fall frost is October 6.

When should I plant Nasturtium in Jackson County, MN?

In Jackson County, MN, plant Nasturtium after the last frost (around April 30) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Jackson County, MN for Nasturtium?

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

Can Nasturtium grow in Jackson County's climate?

Yes — Nasturtium grows well in Jackson County's temperate climate. Jackson County averages a 159-day frost-free season, with last frost around April 30 and first frost around October 6.

🌱

Your Jackson County Garden Planner — Free

A 22-page printable planner built for Jackson County (Zone 5a). 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 Jackson County, MN. Local conditions may vary. Last updated: July 2026.

Sources & credits

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