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When to plant Nasturtium in Adams County, IL

Adams County's spring Nasturtium window runs April 21 through May 12. time plantings around the expected last-frost window for best survival.

When to Plant Nasturtium in Adams County, IL

Adams County, Illinois Zone 6a June

What to do in June

Your garden in Adams County, Illinois is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost April 14
Avg. first frost October 20
Soil temp (4") 69°F
Watering Low
Pest pressure High
Daylight 14.8 hrs
  1. It's harvest week for nasturtium

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

Get ahead of July
  • 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.

Adams County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 20, giving you a growing season of approximately 189 days.

At an elevation of 1,390 feet, Adams County receives approximately 33.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Nasturtium during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Adams County, IL (Zone 6a) Moderate season
189 days
Last Spring Frost April 14
189 growing days
First Fall Frost October 20

Adams County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.3

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✓ Fits season (11 days to spare)
Start indoors: Mar 12 Transplant: Apr 16 🌸 Bloom: Jun 11 – Oct 1
Recommended (50%) ✓ Fits season (14 days to spare)
Start indoors: Mar 17 Transplant: Apr 21 🌸 Bloom: Jun 16 – Oct 6
Safe Start (90%) ✓ Fits season (12 days to spare)
Start indoors: Mar 31 Transplant: May 5 🌸 Bloom: Jun 30 – Oct 20

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 Adams County

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

Soil pH

Your soil pH (6.2–7.3) is within Nasturtium's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Nasturtium will thrive.

How to Plant Nasturtium

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

Succession Planting Nasturtium

4
successive plantings in your 189-day season

Sow every 6.3 weeks. Last sowing by Aug 16 to harvest before frost.

Nasturtium Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/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 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 2.2" 3" 0" ✅ Rainfall sufficient
May 2.2" 4" 0" ✅ Rainfall sufficient
Jun 2.2" 4.5" 0" ✅ Rainfall sufficient
Jul 2.2" 3.7" 0" ✅ Rainfall sufficient
Aug 2.2" 3.5" 0" ✅ Rainfall sufficient
Sep 2.2" 3.1" 0" ✅ Rainfall sufficient
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 2.3" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Adams 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 ~825 GDD — county provides 2,598 GDD Excellent fit

Nasturtium Planting Timeline — Adams County, IL

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors April 21 Apr 21 – May 5
Direct Sow April 21 Apr 21 – May 12
Bloom June 16 Jun 16 – Oct 6

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Direct Sow
June Bloom
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

189 days in Adams County

Growing Tips for Nasturtium in Adams County

Direct sow Nasturtium outdoors after April 14 in Adams 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 Adams County, IL?

Adams County is in Zone 6a with an average last frost of April 14. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Adams County, IL?

Adams County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 20.

When should I plant Nasturtium in Adams County, IL?

In Adams County, IL, plant Nasturtium after the last frost (around April 14) and before the first frost (around October 20). Best results when soil holds above 50°F.

What growing zone is Adams County, IL for Nasturtium?

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

Can Nasturtium grow in Adams County's climate?

Yes — Nasturtium grows well in Adams County's temperate climate. Adams County averages a 189-day frost-free season, with last frost around April 14 and first frost around October 20.

🌱

Your Adams County Garden Planner — Free

A 22-page printable planner built for Adams 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 Adams County, IL. 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.