When to Plant Sunflower in Bucks County, PA
Your May planting checklist for Bucks County, Pennsylvania
Welcome to May in Zone 7a. These are the moves that will have the biggest impact on your growing season.
-
Time to transplant sunflower
Your last frost (April 18) has passed. These warm-season crops can handle outdoor soil now.
June prep starts now
- Starting indoors: sunflower
Sunflowers are tall, cheerful annuals grown for their edible seeds and as pollinator magnets. They come in sizes from 2-foot dwarfs to 12-foot giants.
Bucks County, Pennsylvania is in USDA Zone 7a. The average last spring frost is April 18 and the first fall frost is October 25, giving you a growing season of approximately 190 days.
At an elevation of 958 feet, Bucks County receives approximately 42.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Sunflower during the growing season.
Bucks County Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.6
Drainage
Well Drained
Plant 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 Bucks County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (5.0–6.6) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Bucks County is excellent for Sunflower — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.5%). Annual compost additions will help Sunflower.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Jul 17 to harvest before frost.
Plant 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 | — | 3.1" | 0" | ❄️ Dormant |
| Feb | — | 2.8" | 0" | ❄️ Dormant |
| Mar | — | 3.8" | 0" | ❄️ Dormant |
| Apr | 2.2" | 3.3" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 3.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 4.8" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Nov | — | 2.8" | 0" | ❄️ Dormant |
| Dec | — | 3.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Bucks 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 — Bucks County, PA
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 28 | Feb 28 – Mar 14 |
| Transplant Outdoors | May 2 | May 2 – May 16 |
| Direct Sow | April 25 | Apr 25 – May 16 |
| Harvest | July 11 | Jul 11 – Aug 29 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| 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: too_acidic
🗺️ USDA Zone
Zone 7a
📆 Growing Season
190 days in Bucks County
Growing Tips for Sunflower in Bucks County
Direct sow Sunflower outdoors after April 18 in Bucks 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 after last frost. Stake tall varieties in windy areas. Harvest seed heads when the back turns brown and seeds are plump. Dry heads upside down.
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 Bucks County, PA?
Bucks County is in Zone 7a with an average last frost of April 18. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Bucks County, PA?
Bucks County, Pennsylvania is in USDA Hardiness Zone 7a. The average last spring frost is April 18 and first fall frost is October 25.
Your Bucks County Garden Planner — Free
A 24-page printable planner built for Bucks 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.