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When to plant Nasturtium in Windham County, CT

Plant Nasturtium in Windham County after April 29; the prime window is May 6–May 27.

When to Plant Nasturtium in Windham County, CT

Windham County, Connecticut Zone 6a August

August in Windham County, Connecticut — your action list

Your Windham County, Connecticut garden is entering a new phase. Here's what's on the schedule for August and why each task matters now.

Avg. last frost April 29
Avg. first frost October 16
Soil temp (4") 81°F
Watering Moderate
Pest pressure High
Daylight 13.7 hrs
  1. Bring in the nasturtium

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

September will be here before you know it — start on
  • 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.

Windham County, Connecticut is in USDA Zone 6a. The average last spring frost is April 29 and the first fall frost is October 16, giving you a growing season of approximately 170 days.

At an elevation of 110 feet, Windham County receives approximately 41.6 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
Windham County, CT (Zone 6a) Moderate season
170 days
Last Spring Frost April 29
170 growing days
First Fall Frost October 16

Windham County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.7

Drainage

Well Drained

Nasturtium Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 25 Transplant: Apr 29 🌸 Bloom: Jun 24 – Oct 14
Recommended (50%) ✗ May not fit
Start indoors: Apr 1 Transplant: May 6 🌸 Bloom: Jul 1 – Oct 21
Safe Start (90%) ✗ May not fit
Start indoors: Apr 17 Transplant: May 22 🌸 Bloom: Jul 17 – Nov 6

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 Windham County

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

Soil pH

Your soil pH (5.1–6.7) is more acidic than Nasturtium prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Nasturtium.

How to Plant Nasturtium

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

Succession Planting Nasturtium

3
successive plantings in your 170-day season

Sow every 6.3 weeks. Last sowing by Aug 12 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 3.2" 0" ❄️ Dormant
Feb 3" 0" ❄️ Dormant
Mar 3.2" 0" ❄️ Dormant
Apr 2.2" 3.3" 0" ✅ Rainfall sufficient
May 2.2" 3.8" 0" ✅ Rainfall sufficient
Jun 2.2" 3.7" 0" ✅ Rainfall sufficient
Jul 2.2" 4.9" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.2" 0" ✅ Rainfall sufficient
Oct 2.2" 3.2" 0" ✅ Rainfall sufficient
Nov 3.2" 0" ❄️ Dormant
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Windham 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 2,337 GDD Excellent fit

Nasturtium Planting Timeline — Windham County, CT

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors April 1 Apr 1 – Apr 15
Transplant Outdoors May 6 May 6 – May 20
Direct Sow May 6 May 6 – May 27
Bloom July 1 Jul 1 – Oct 21

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: too_acidic

🗺️ USDA Zone

Zone 6a

📆 Growing Season

170 days in Windham County

Growing Tips for Nasturtium in Windham County

Direct sow Nasturtium outdoors after April 29 in Windham 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 Windham County, CT?

Windham County is in Zone 6a with an average last frost of April 29. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Windham County, CT?

Windham County, Connecticut is in USDA Hardiness Zone 6a. The average last spring frost is April 29 and first fall frost is October 16.

When should I plant Nasturtium in Windham County, CT?

In Windham County, CT, plant Nasturtium after the last frost (around April 29) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Windham County, CT for Nasturtium?

Windham 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 Windham County's climate?

Yes — Nasturtium grows well in Windham County's temperate climate. Windham County averages a 170-day frost-free season, with last frost around April 29 and first frost around October 16.

🌱

Your Windham County Garden Planner — Free

A 22-page printable planner built for Windham 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 Windham County, CT. Local conditions may vary. Last updated: August 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.