When to Plant Sunflower in Klickitat County, WA
Top priorities for Klickitat County, Washington gardeners in July
Here's what deserves your attention in Klickitat County, Washington this month. Everything below is tailored to Zone 7b and timed around your local frost dates.
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Harvest sunflower as they ripen
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
August prep starts now
- 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.
Klickitat County, Washington is in USDA Zone 7b. The average last spring frost is April 14 and the first fall frost is October 19, giving you a growing season of approximately 188 days.
At an elevation of 466 feet, Klickitat County receives approximately 42 inches of rainfall annually with predominantly silt loam soil. Summer highs average 77°F, so choose short-season varieties of Sunflower to ensure they mature before fall.
Klickitat County Soil Profile
Soil Type
Silt Loam
Soil pH
5.3-6.8
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 Klickitat County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (5.3–6.8) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Klickitat County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.7%) — Sunflower will thrive.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Jul 11 to harvest before frost.
Sunflower Water Budget
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 | — | 5.4" | 0" | ❄️ Dormant |
| Feb | — | 4.3" | 0" | ❄️ Dormant |
| Mar | — | 4.4" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 1.4" | 0.8" | 💧 Light watering |
| Jul | 2.2" | 0.7" | 1.5" | 🚿 Regular watering |
| Aug | 2.2" | 0.9" | 1.3" | 🚿 Regular watering |
| Sep | 2.2" | 1.6" | 0.6" | 💧 Light watering |
| Oct | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Nov | — | 6.7" | 0" | ❄️ Dormant |
| Dec | — | 6.5" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Klickitat 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 — Klickitat County, WA
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 24 | Mar 24 – Apr 7 |
| Transplant Outdoors | April 14 | Apr 14 – Apr 28 |
| Direct Sow | April 14 | Apr 14 – May 5 |
| Bloom | July 7 | Jul 7 – Oct 27 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | 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 7b
📆 Growing Season
188 days in Klickitat County
Growing Tips for Sunflower in Klickitat County
Direct sow Sunflower outdoors after April 14 in Klickitat 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.
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 Klickitat County, WA?
Klickitat County is in Zone 7b with an average last frost of April 14. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Klickitat County, WA?
Klickitat County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 14 and first fall frost is October 19.
Your Klickitat County Garden Planner — Free
A 22-page printable planner built for Klickitat 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.