When to plant Sunflower in Mesa County, CO
In Mesa County, plant Sunflower in spring between May 1 and May 22, once soil temps hold above 50°F. Mesa County's last frost averages May 1, so most warm-season crops establish quickly once soil holds above 60°F. For a fall crop, sow between and — roughly 70–100 days before the first frost on October 9.
When to Plant Sunflower in Mesa County, CO
What to do in June
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.
July will be here before you know it — start on
- First harvests: sunflower
Sunflower (Helianthus annuus) is a fast-growing North American native annual famous for its towering stems and brilliant yellow heads. It thrives in full sun and heat, producing large, pollen-rich blooms that attract bees, butterflies, and seed-eating birds. Varieties range from 18-inch dwarfs to 12-foot giants and nearly every color except blue.
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 Sunflower during the growing season.
Mesa County Soil Profile
Soil Type
Loam
Soil pH
6.7-8.1
Drainage
Well Drained
Sunflower 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 Mesa County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (6.7–8.1) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Mesa County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Sunflower.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Jul 01 to harvest before frost.
Sunflower Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Sunflower
Sunflower 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 | Sunflower 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 | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Jul | 2.2" | 2.1" | 0.1" | 💧 Light watering |
| Aug | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Oct | 2.2" | 1.8" | 0.4" | 💧 Light 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.
Sunflower 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.
Sunflower Planting Timeline — Mesa County, CO
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 10 | Apr 10 – Apr 24 |
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Direct Sow | May 1 | May 1 – May 22 |
| Bloom | July 24 | Jul 24 – Oct 30 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
70–100 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
161 days in Mesa County
Growing Tips for Sunflower in Mesa County
Direct sow Sunflower outdoors after May 01 in Mesa County when soil has warmed and frost danger has passed.
Common pests for Sunflower in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Mesa County receives only 23" of rain annually. Sunflower needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct-sow 1 inch deep after last frost; germination takes 7-14 days at 65-75°F soil. Sunflowers dislike root disturbance so direct sowing is strongly preferred over transplanting. Plant in succession every 2 weeks for extended bloom. Stake tall varieties. Avoid overwatering — they tolerate drought once established. Birds will self-deadhead seed heads; leave them up through fall for wildlife.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Sunflower in Other Locations
Frequently Asked Questions
When should I plant Sunflower in Mesa County, CO?
Mesa County is in Zone 7a with an average last frost of May 1. Plan your Sunflower 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 Sunflower in Mesa County, CO?
In Mesa County, CO, plant Sunflower 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, CO for Sunflower?
Mesa County sits in USDA Zone 7a. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.
Can Sunflower grow in Mesa County's climate?
Yes — Sunflower grows well in Mesa County's temperate climate. Mesa 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.