When to Plant Sunflower in Cass County, NE
Your June game plan for Cass County, Nebraska
Your garden in Cass County, Nebraska is working on a schedule, even when you're not. Here's where you should be this June.
Get ahead of July
- 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.
Cass County, Nebraska is in USDA Zone 6a. The average last spring frost is April 22 and the first fall frost is October 11, giving you a growing season of approximately 172 days.
At an elevation of 779 feet, Cass County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Sunflower during the growing season.
Cass County Soil Profile
Soil Type
Loam
Soil pH
6.3-7.8
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 Cass County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (6.3–7.8) overlaps with Sunflower's range (6.0–7.5), though not a perfect match.
Soil Texture
The loam soil in Cass County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.6%). Annual compost additions will help Sunflower.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Jul 03 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 | — | 0.6" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.7" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Nov | — | 0.6" | 0" | ❄️ Dormant |
| Dec | — | 0.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Cass 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 — Cass County, NE
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 1 | Apr 1 – Apr 15 |
| Transplant Outdoors | April 29 | Apr 29 – May 13 |
| Direct Sow | April 29 | Apr 29 – May 20 |
| Bloom | July 22 | Jul 22 – Oct 14 |
Plant 1" deep · 18" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Transplant Outdoors Direct Sow |
| 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 6a
📆 Growing Season
172 days in Cass County
Growing Tips for Sunflower in Cass County
Direct sow Sunflower outdoors after April 22 in Cass 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.
Cass County receives only 21" 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 Cass County, NE?
Cass County is in Zone 6a with an average last frost of April 22. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Cass County, NE?
Cass County, Nebraska is in USDA Hardiness Zone 6a. The average last spring frost is April 22 and first fall frost is October 11.
Your Cass County Garden Planner — Free
A 22-page printable planner built for Cass County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.