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When to Plant Geraniums in Durham County, NC

Durham County, North Carolina Zone 8a June

Top priorities for Durham County, North Carolina gardeners in June

Your Durham County, North Carolina garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 2
Avg. first frost November 3
Soil temp (4") 77°F
Watering Moderate
Pest pressure High
Daylight 14.4 hrs
  1. Indoor seed-starting week for geraniums

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

  2. Basket week: geraniums

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

July will be here before you know it — start on
  • First harvests: geraniums

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Geraniums (Pelargonium × hortorum) are tender perennials grown as warm-season annuals throughout North America. Prized for their bold flower clusters, long bloom period, and tolerance of summer heat when planted in well-drained soil, they anchor window boxes, containers, and bed borders from late spring until hard frost. Zones 9b–11b can overwinter plants in the ground.

Durham County, North Carolina is in USDA Zone 8a. The average last spring frost is April 2 and the first fall frost is November 3, giving you a growing season of approximately 215 days.

At an elevation of 727 feet, Durham County receives approximately 40.1 inches of rainfall annually with predominantly clay loam soil. Summer highs average 90°F, providing good warmth for Geraniums during the growing season. Clay soil retains moisture well for Geraniums, but amend with compost to improve drainage and prevent root rot.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Durham County, NC (Zone 8a) Long season
215 days
Last Spring Frost April 2
215 growing days
First Fall Frost November 3

Durham County Soil Profile

Soil Type

Clay Loam

Soil pH

5.6-6.7

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Jan 13 Transplant: Mar 17 🌸 Bloom: May 26 – Oct 13
Recommended (50%) ✓ Fits season (12 days to spare)
Start indoors: Jan 22 Transplant: Mar 26 🌸 Bloom: Jun 4 – Oct 22
Safe Start (90%) ✓ Fits season (7 days to spare)
Start indoors: Feb 10 Transplant: Apr 14 🌸 Bloom: Jun 23 – Nov 10

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 Durham County

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

Soil pH

Your soil pH (5.6–6.7) overlaps with Geraniums's range (6.0–7.0), though not a perfect match.

Soil Texture

The clay loam soil in Durham County is excellent for Geraniums — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Geraniums.

How to Plant Geraniums

0.1"
Planting Depth
12"
Between Plants
14"
Between Rows

Succession Planting Geraniums

3
successive plantings in your 215-day season

Sow every 8 weeks. Last sowing by Jul 26 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 415 gal / 100 sq ft

Monthly Watering Guide for Geraniums

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

Month Geraniums Needs Rainfall You Supplement Action
Jan 3.6" 0" ❄️ Dormant
Feb 3.3" 0" ❄️ Dormant
Mar 3.8" 0" ❄️ Dormant
Apr 4.3" 2.7" 1.6" 💧 Light watering
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 3.3" 1" 💧 Light watering
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 3.8" 0.5" 💧 Light watering
Sep 4.3" 3" 1.3" 💧 Light watering
Oct 4.3" 2.4" 1.9" 💧 Light watering
Nov 4.3" 3.4" 0.9" 💧 Light watering
Dec 3.4" 0" ❄️ Dormant

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

Geraniums 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.

Geraniums needs ~1,488 GDD — county provides 3,762 GDD Excellent fit

Geraniums Planting Timeline — Durham County, NC

Geraniums Planting Calendar

Activity When Date Range
Start Indoors January 22 Jan 22 – Feb 5
Transplant Outdoors March 26 Mar 26 – Apr 9
Bloom June 4 Jun 4 – Oct 22

Plant 0.1" deep · 12" apart · Rows 14" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors
March Transplant Outdoors
April Transplant Outdoors
May
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

215 days in Durham County

Growing Tips for Geraniums in Durham County

Direct sow Geraniums outdoors after April 02 in Durham County when soil has warmed and frost danger has passed.

With Durham County's clay soil (31% clay), work in 3-4 inches of compost before planting Geraniums. Avoid tilling when soil is wet to prevent compaction.

General growing tips

Start seeds indoors 10–12 weeks before last frost — germination is slow and erratic without bottom heat (70–75°F). Transplant after frost danger passes. Geraniums rarely direct-sown; cuttings or transplants are the standard. Deadhead spent umbels weekly to maintain continuous bloom. Let soil dry slightly between waterings to prevent root rot. In zones 10–11 plants may be left in ground year-round or overwintered as houseplants.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Geraniums in Durham County, NC?

Durham County is in Zone 8a with an average last frost of April 2. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Durham County, NC?

Durham County, North Carolina is in USDA Hardiness Zone 8a. The average last spring frost is April 2 and first fall frost is November 3.

🌱

Your Durham County Garden Planner — Free

A 22-page printable planner built for Durham County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Durham County, NC. 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.