When to plant Sunflower in Rice County, KS
In Rice County, plant Sunflower in spring between April 16 and May 7, once soil temps hold above 50°F. Rice County's last frost averages April 16, so time plantings around the expected last-frost window for best survival. For a fall crop, sow between and — roughly 70–100 days before the first frost on October 18.
When to Plant Sunflower in Rice County, KS
July to-do list for Rice County, Kansas
A quick July briefing for Rice County, Kansas gardeners — what's urgent, what's next, and what can wait.
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Basket week: sunflower
Check every 1–2 days. Many of these get tough or go to seed if you wait too long.
Coming up in August — start thinking about
- 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.
Rice County, Kansas is in USDA Zone 6b. The average last spring frost is April 16 and the first fall frost is October 18, giving you a growing season of approximately 185 days.
At an elevation of 1,019 feet, Rice County receives approximately 24.6 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Sunflower during the growing season.
Rice County Soil Profile
Soil Type
Loam
Soil pH
6.2-7.3
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 Rice County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (6.2–7.3) is within Sunflower's preferred range (6.0–7.5).
Soil Texture
The loam soil in Rice County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.7%). Annual compost additions will help Sunflower.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Jul 10 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 | — | 0.5" | 0" | ❄️ Dormant |
| Feb | — | 0.8" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 3.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Nov | — | 0.9" | 0" | ❄️ Dormant |
| Dec | — | 0.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Rice 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 — Rice County, KS
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 26 | Mar 26 – Apr 9 |
| Transplant Outdoors | April 16 | Apr 16 – Apr 30 |
| Direct Sow | April 16 | Apr 16 – May 7 |
| Bloom | July 9 | Jul 9 – Oct 8 |
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: ideal
🗺️ USDA Zone
Zone 6b
📆 Growing Season
185 days in Rice County
Growing Tips for Sunflower in Rice County
Direct sow Sunflower outdoors after April 16 in Rice 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.
Rice County receives only 25" 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 Rice County, KS?
Rice County is in Zone 6b with an average last frost of April 16. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Rice County, KS?
Rice County, Kansas is in USDA Hardiness Zone 6b. The average last spring frost is April 16 and first fall frost is October 18.
When should I plant Sunflower in Rice County, KS?
In Rice County, KS, plant Sunflower after the last frost (around April 16) and before the first frost (around October 18). Best results when soil holds above 50°F.
What growing zone is Rice County, KS for Sunflower?
Rice County sits in USDA Zone 6b. Sunflower grows reliably in zones 2a through 11b, so it's a good fit here.
Can Sunflower grow in Rice County's climate?
Yes — Sunflower grows well in Rice County's temperate climate. Rice County averages a 185-day frost-free season, with last frost around April 16 and first frost around October 18.
Your Rice County Garden Planner — Free
A 22-page printable planner built for Rice County (Zone 6b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.