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When to Plant Zucchini in Barnwell County, SC

Barnwell County, South Carolina Zone 8b May

Your May planting checklist for Barnwell County, South Carolina

May is a pivotal month for Barnwell County, South Carolina gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost March 22
Avg. first frost November 10
Soil temp (4") 72°F
Watering Moderate
Pest pressure High
Daylight 13.7 hrs
  1. Basket week: zucchini

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

Looking ahead to June
  • First harvests: zucchini

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Zucchini is an incredibly prolific summer squash that can produce an abundance of fruit from just a few plants. It is versatile in the kitchen from grilling to baking.

Barnwell County, South Carolina is in USDA Zone 8b. The average last spring frost is March 22 and the first fall frost is November 10, giving you a growing season of approximately 233 days.

At an elevation of 157 feet, Barnwell County receives approximately 48.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Zucchini may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Zucchini will need more frequent watering and organic matter to retain nutrients.

Barnwell County, SC (Zone 8b) Long season
233 days
Last Spring Frost March 22
233 growing days
First Fall Frost November 10

Barnwell County Soil Profile

Soil Type

Sandy Loam

Soil pH

5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (117 days to spare)
Start indoors: Feb 11 Transplant: Mar 25 🍅 Harvest: May 13 – Jul 8
Recommended (50%) ✓ Fits season (114 days to spare)
Start indoors: Feb 22 Transplant: Apr 5 🍅 Harvest: May 24 – Jul 19
Safe Start (90%) ✓ Fits season (114 days to spare)
Start indoors: Mar 11 Transplant: Apr 22 🍅 Harvest: Jun 10 – Aug 5

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 Barnwell County

How your county's soil matches Zucchini's growing requirements.

Soil pH

Your soil pH (5.0–6.3) is more acidic than Zucchini prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Barnwell County warms quickly in spring but drains fast. Zucchini will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Zucchini.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Zucchini.

How to Plant Zucchini

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Succession Planting Zucchini

6
successive plantings in your 233-day season

Sow every 5.1 weeks. Last sowing by Sep 11 to harvest before frost.

Plant Water Budget

Plant needs
1.2″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Zucchini

Zucchini needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.

Month Zucchini Needs Rainfall You Supplement Action
Jan 3.8" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 5.2" 4.5" 0.7" 💧 Light watering
Apr 5.2" 3.9" 1.3" 💧 Light watering
May 5.2" 3.7" 1.5" 💧 Light watering
Jun 5.2" 4.3" 0.9" 💧 Light watering
Jul 5.2" 5.2" 0" ✅ Rainfall sufficient
Aug 5.2" 5" 0.2" 💧 Light watering
Sep 5.2" 3.9" 1.3" 💧 Light watering
Oct 5.2" 2.8" 2.4" 💧 Light watering
Nov 5.2" 3.9" 1.3" 💧 Light watering
Dec 3.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Barnwell County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Zucchini 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.

Zucchini needs ~1,194 GDD — county provides 5,300 GDD Excellent fit

Zucchini Planting Timeline — Barnwell County, SC

Zucchini Planting Calendar

Activity When Date Range
Start Indoors February 22 Feb 22 – Mar 8
Transplant Outdoors April 5 Apr 5 – Apr 19
Direct Sow March 29 Mar 29 – Apr 19
Harvest May 24 May 24 – Jul 19

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors Direct Sow
April Transplant Outdoors Direct Sow
May Harvest
June Harvest
July Harvest
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.2"/week · Natural rainfall sufficient

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8b

📆 Growing Season

233 days in Barnwell County

Growing Tips for Zucchini in Barnwell County

Direct sow Zucchini outdoors after March 22 in Barnwell County when soil has warmed and frost danger has passed.

Sandy soil in Barnwell County dries quickly — mulch Zucchini with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 97°F in Barnwell County, provide afternoon shade for Zucchini and water deeply in the morning.

Your generous 233.0-day season in Barnwell County allows multiple plantings of Zucchini. Sow every 22.0 days for continuous harvest.

Common pests for Zucchini in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow after last frost. Harvest when fruits are 6-8 inches long for best flavor and texture. Check plants daily in summer as fruits can double in size overnight.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Zucchini in Barnwell County, SC?

Barnwell County is in Zone 8b with an average last frost of March 22. Plan your Zucchini planting based on this frost date — see the calendar above for exact timing.

What planting zone is Barnwell County, SC?

Barnwell County, South Carolina is in USDA Hardiness Zone 8b. The average last spring frost is March 22 and first fall frost is November 10.

🌱

Your Barnwell County Garden Planner — Free

A 24-page printable planner built for Barnwell 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Barnwell County, SC. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.