When to Plant Sunflower in Williamsburg County, SC
Your May game plan for Williamsburg County, South Carolina
Each item below is timed to Williamsburg County, South Carolina's frost dates and soil temperatures. Skip nothing, stress about nothing.
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Get sunflower seeds going inside
Your window is short. These crops want several weeks of indoor growth before they go outside.
Before June arrives, get these ready
- First harvests: 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.
Williamsburg County, South Carolina is in USDA Zone 8b. The average last spring frost is March 22 and the first fall frost is November 13, giving you a growing season of approximately 236 days.
At an elevation of 139 feet, Williamsburg County receives approximately 52.7 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 92°F, providing good warmth for Sunflower during the growing season. Sandy soil warms quickly in spring — great for early planting — but Sunflower will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sunflower root diseases.
Williamsburg County Soil Profile
Soil Type
Sandy Loam
Soil pH
5-6.4
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 Williamsburg County
How your county's soil matches Sunflower's growing requirements.
Soil pH
Your soil pH (5.0–6.4) is more acidic than Sunflower prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in Williamsburg County warms quickly in spring but drains fast. Sunflower will need more frequent watering and regular compost additions to retain nutrients.
Drainage
Sunflower prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.
Organic Matter
Organic matter is low (1.9%). Add 2-3 inches of compost before planting Sunflower.
How to Plant Sunflower
Succession Planting Sunflower
Sow every 8 weeks. Last sowing by Aug 05 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 | — | 4.2" | 0" | ❄️ Dormant |
| Feb | — | 4.5" | 0" | ❄️ Dormant |
| Mar | 2.2" | 4.4" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 4.1" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 5.9" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 5.2" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 3.6" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 4.3" | 0" | ✅ Rainfall sufficient |
| Dec | — | 4.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Williamsburg 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 — Williamsburg County, SC
Sunflower Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 1 | Feb 1 – Feb 15 |
| Transplant Outdoors | April 5 | Apr 5 – Apr 19 |
| Direct Sow | March 29 | Mar 29 – Apr 19 |
| Harvest | June 14 | Jun 14 – Aug 2 |
Plant 1" deep · 18" apart · Rows 30" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Direct Sow |
| April | Transplant Outdoors Direct Sow |
| May | — |
| June | Harvest |
| 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 8b
📆 Growing Season
236 days in Williamsburg County
Growing Tips for Sunflower in Williamsburg County
Direct sow Sunflower outdoors after March 22 in Williamsburg County when soil has warmed and frost danger has passed.
Sandy soil in Williamsburg County dries quickly — mulch Sunflower with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
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 Williamsburg County, SC?
Williamsburg County is in Zone 8b with an average last frost of March 22. Plan your Sunflower planting based on this frost date — see the calendar above for exact timing.
What planting zone is Williamsburg County, SC?
Williamsburg County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 22 and first fall frost is November 13.
Your Williamsburg County Garden Planner — Free
A 24-page printable planner built for Williamsburg County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.