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When to plant Geraniums in Mesa County County,

Mesa County County's 161-day season only supports one Geraniums planting per year. Sow between May 1 and May 15 for the best chance at full maturity before October 9.

When to Plant Geraniums in Mesa County, CO

Mesa County, Colorado Zone 7a June

Your June planting checklist for Mesa County, Colorado

Here's what deserves your attention in Mesa County, Colorado this month. Everything below is tailored to Zone 7a and timed around your local frost dates.

Avg. last frost May 1
Avg. first frost October 9
Soil temp (4") 58°F
Watering High
Pest pressure High
Daylight 14.7 hrs
Coming up in July — start thinking about
  • Starting indoors: geraniums
  • 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.

Mesa County, Colorado is in USDA Zone 7a. The average last spring frost is May 1 and the first fall frost is October 9, giving you a growing season of approximately 161 days.

At an elevation of 6,091 feet, Mesa County receives approximately 23.3 inches of rainfall annually with predominantly loam soil. Summer highs average 91°F, providing good warmth for Geraniums during the growing season.

Annual Blooms in Multi-season Pollinator-friendly Deer-resistant Good for cutting Fragrant
Mesa County, CO (Zone 7a) Moderate season
161 days
Last Spring Frost May 1
161 growing days
First Fall Frost October 9
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Mesa County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.1

Drainage

Well Drained

Geraniums Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 11 Transplant: Apr 22 🌸 Bloom: Jul 1 – Oct 21
Recommended (50%) ✗ May not fit
Start indoors: Feb 20 Transplant: May 1 🌸 Bloom: Jul 10 – Oct 30
Safe Start (90%) ✗ May not fit
Start indoors: Mar 5 Transplant: May 14 🌸 Bloom: Jul 23 – Nov 12

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 Mesa County

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

Soil pH

Your soil pH (6.7–8.1) is more alkaline than Geraniums prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Geraniums.

How to Plant Geraniums

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

Succession Planting Geraniums

2
successive plantings in your 161-day season

Sow every 8 weeks. Last sowing by Jul 01 to harvest before frost.

Geraniums Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 674 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.7" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.5" 0" ❄️ Dormant
May 4.3" 2.6" 1.7" 💧 Light watering
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.5" 1.8" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 1.8" 2.5" 🚿 Regular watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Mesa 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 ~1,551 GDD — county provides 2,938 GDD Excellent fit

Geraniums Planting Timeline — Mesa County, CO

Geraniums Planting Calendar

Activity When Date Range
Start Indoors February 20 Feb 20 – Mar 6
Transplant Outdoors May 1 May 1 – May 15
Bloom July 10 Jul 10 – Oct 30

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

161 days in Mesa County

Growing Tips for Geraniums in Mesa County

Direct sow Geraniums outdoors after May 01 in Mesa County when soil has warmed and frost danger has passed.

Mesa County receives only 23" of rain annually. Geraniums needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Mesa County, CO?

Mesa County is in Zone 7a with an average last frost of May 1. Plan your Geraniums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Mesa County, CO?

Mesa County, Colorado is in USDA Hardiness Zone 7a. The average last spring frost is May 1 and first fall frost is October 9.

When should I plant Geraniums in Mesa County County, ?

In Mesa County County, , plant Geraniums after the last frost (around May 1) and before the first frost (around October 9). Best results when soil holds above 50°F.

What growing zone is Mesa County County, for Geraniums?

Mesa County County sits in USDA Zone 7a. Geraniums grows reliably in zones 2a through 11b, so it's a good fit here.

Can Geraniums grow in Mesa County County's climate?

Yes — Geraniums grows well in Mesa County County's temperate climate. Mesa County County averages a 161-day frost-free season, with last frost around May 1 and first frost around October 9.

🌱

Your Mesa County Garden Planner — Free

A 22-page printable planner built for Mesa County (Zone 7a). 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 Mesa County, CO. 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.