When to plant Nasturtium in Coles County, IL
In Zone 6a (Coles County), direct-sow Nasturtium between April 21 and May 12 for spring, after the April 14 last-frost mark.
When to Plant Nasturtium in Coles County, IL
What to do in July
We've pulled the most time-sensitive tasks for Coles County, Illinois this July and put them front and centre. Tackle them in order.
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Harvest nasturtium as they ripen
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Looking ahead to August
- First harvests: nasturtium
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.
Coles County, Illinois is in USDA Zone 6a. The average last spring frost is April 14 and the first fall frost is October 17, giving you a growing season of approximately 186 days.
At an elevation of 779 feet, Coles County receives approximately 34.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Nasturtium during the growing season.
Coles County Soil Profile
Soil Type
Silt Loam
Soil pH
6-7.2
Drainage
Well Drained
Nasturtium Planting Risk Windows
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 Coles County
How your county's soil matches Nasturtium's growing requirements.
Soil pH
Your soil pH (6.0–7.2) is within Nasturtium's preferred range (6.0–8.0).
Soil Texture
The silt loam soil in Coles County is excellent for Nasturtium — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.1%) — Nasturtium will thrive.
How to Plant Nasturtium
Succession Planting Nasturtium
Sow every 6.3 weeks. Last sowing by Aug 13 to harvest before frost.
Nasturtium Water Budget
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 | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 2.4" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.5" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Coles 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 Planting Timeline — Coles 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
| Month | Activities |
|---|---|
| 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
186 days in Coles County
Growing Tips for Nasturtium in Coles County
Direct sow Nasturtium outdoors after April 14 in Coles 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
Check more plant combinations with our Companion Planting Checker →
Nasturtium in Other Locations
Frequently Asked Questions
When should I plant Nasturtium in Coles County, IL?
Coles 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 Coles County, IL?
Coles County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 14 and first fall frost is October 17.
When should I plant Nasturtium in Coles County, IL?
In Coles County, IL, plant Nasturtium after the last frost (around April 14) and before the first frost (around October 17). Best results when soil holds above 50°F.
What growing zone is Coles County, IL for Nasturtium?
Coles 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 Coles County's climate?
Yes — Nasturtium grows well in Coles County's temperate climate. Coles County averages a 186-day frost-free season, with last frost around April 14 and first frost around October 17.
Your Coles County Garden Planner — Free
A 22-page printable planner built for Coles 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.