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When to Plant Nasturtium in Custer County, OK

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.

Custer County, Oklahoma is in USDA Zone 7b. The average last spring frost is April 8 and the first fall frost is October 31, giving you a growing season of approximately 206 days.

At an elevation of 767 feet, Custer County receives approximately 31.6 inches of rainfall annually with predominantly loam soil. Summer highs average 89°F, providing good warmth for Nasturtium during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Custer County, OK (Zone 7b) Long season
206 days
Last Spring Frost April 8
206 growing days
First Fall Frost October 31

Custer County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Monthly Watering Guide for Nasturtium

Nasturtium needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Nasturtium Needs Rainfall You Supplement Action
Jan 0.8" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4" 0.3" 💧 Light watering
Jun 4.3" 5.4" 0" ✅ Rainfall sufficient
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 4.2" 0.1" 💧 Light watering
Sep 4.3" 2.7" 1.6" 💧 Light watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Custer County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Nasturtium Planting Timeline — Custer County, OK

Nasturtium Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow April 8 Apr 8 – Apr 29
Bloom June 3 Jun 3 – Oct 21

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
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

Low — drought tolerant

📅 Days to Maturity

55–65 days

🧪 Soil pH

Needs 6–8 · Your soil: N/A

🗺️ USDA Zone

Zone 7b

📆 Growing Season

206 days in Custer County

Growing Tips for Custer County

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 Custer County, OK?

Custer County is in Zone 7b with an average last frost of April 8. Plan your Nasturtium planting based on this frost date — see the calendar above for exact timing.

What planting zone is Custer County, OK?

Custer County, Oklahoma is in USDA Hardiness Zone 7b. The average last spring frost is April 8 and first fall frost is October 31.

🌱

Your Custer County Garden Planner — Free

A 22-page printable planner built for Custer County (Zone 7b). 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 Custer County, OK. Local conditions may vary. Last updated: July 2026.

Sources & credits

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