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When to plant Nasturtium in Pullman, MI

In Zone 6a (Pullman), direct-sow Nasturtium between May 9 and May 30 for spring, after the May 2 last-frost mark.

When to Plant Nasturtium in Pullman, MI

Allegan County, Michigan Zone 6a July

Your July gardening checklist

July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Allegan County, Michigan.

Avg. last frost May 2
Avg. first frost October 14
Soil temp (4") 77°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. Start harvesting nasturtium

    If you can't use it all right away, check the food-preservation section of your planner.

Coming up in August — start thinking about
  • 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.

Pullman, Michigan is in USDA Zone 6a. The average last spring frost is May 2 and the first fall frost is October 14, giving you a growing season of approximately 165 days.

At an elevation of 1,257 feet, Allegan County receives approximately 37.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Nasturtium during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Pullman, MI (Zone 6a) Moderate season
165 days
Last Spring Frost May 2
165 growing days
First Fall Frost October 14

Pullman Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.7

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 30 Transplant: May 4 🌸 Bloom: Jun 29 – Oct 19
Recommended (50%) ✗ May not fit
Start indoors: Apr 4 Transplant: May 9 🌸 Bloom: Jul 4 – Oct 24
Safe Start (90%) ✗ May not fit
Start indoors: Apr 23 Transplant: May 28 🌸 Bloom: Jul 23 – Nov 12

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 Pullman

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

Soil pH

Your soil pH (6.2–6.7) is within Nasturtium's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.3%) — 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 165-day season

Sow every 6.3 weeks. Last sowing by Aug 10 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 1.8" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 2.2" 3.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.9" 0" ✅ Rainfall sufficient
Jul 2.2" 4.2" 0" ✅ Rainfall sufficient
Aug 2.2" 3.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.6" 0" ✅ Rainfall sufficient
Oct 2.2" 3.1" 0" ✅ Rainfall sufficient
Nov 2.8" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Allegan 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 ~870 GDD — county provides 2,392 GDD Excellent fit

Nasturtium Planting Timeline — Pullman, MI

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors April 4 Apr 4 – Apr 18
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 9 May 9 – May 30
Bloom July 4 Jul 4 – Oct 24

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 6a

📆 Growing Season

165 days in Allegan County

Growing Tips for Nasturtium in Pullman

Direct sow Nasturtium outdoors after May 02 in Allegan 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 →

When should I plant Nasturtium in Pullman, MI?

In Pullman, MI, plant Nasturtium after the last frost (around May 2) and before the first frost (around October 14). Best results when soil holds above 50°F.

What growing zone is Pullman, MI for Nasturtium?

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

Can Nasturtium grow in Pullman's climate?

Yes — Nasturtium grows well in Pullman's temperate climate. Pullman averages a 165-day frost-free season, with last frost around May 2 and first frost around October 14.

🌱

Your Allegan County Garden Planner — Free

A 22-page printable planner built for Allegan County (Zone 6a). 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 Allegan County, MI. Local conditions may vary. Last updated: July 2026.