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When to Plant Carrots in Marlboro County, SC

Marlboro County, South Carolina Zone 8a April

What to do in April

Welcome to April in Zone 8a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 23
Avg. first frost November 6
Soil temp (4") 62°F
Watering Moderate
Pest pressure High
Daylight 12.9 hrs
Before May arrives, get these ready
  • First harvests: carrots

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Carrots are a popular root vegetable available in orange, purple, white, and yellow varieties. They are rich in beta-carotene and have a sweet, earthy flavor.

Marlboro County, South Carolina is in USDA Zone 8a. The average last spring frost is March 23 and the first fall frost is November 6, giving you a growing season of approximately 228 days.

At an elevation of 132 feet, Marlboro County receives approximately 52.7 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91°F, providing good warmth for Carrots during the growing season. Clay soil retains moisture well for Carrots, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Carrots root diseases.

Marlboro County, SC (Zone 8a) Long season
228 days
Last Spring Frost March 23
228 growing days
First Fall Frost November 6
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Marlboro County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (133 days to spare)
Transplant: Mar 16 🍅 Harvest: May 18 – Jun 22
Recommended (50%) ✓ Fits season (130 days to spare)
Transplant: Mar 23 🍅 Harvest: May 25 – Jun 29
Safe Start (90%) ✓ Fits season (129 days to spare)
Transplant: Apr 10 🍅 Harvest: Jun 12 – Jul 17

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 Marlboro County

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

Soil pH

Your soil pH (5.7–6.5) overlaps with Carrots's range (6.0–6.8), though not a perfect match.

Soil Texture

Your soil has 34% clay, which can cause forked or stunted roots for Carrots. Use raised beds with loose, sandy mix for best results.

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Carrots.

How to Plant Carrots

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Carrots

4
successive plantings in your 228-day season

Sow every 6.9 weeks. Last sowing by Aug 18 to harvest before frost.

For a dedicated fall crop, sow by Aug 28.

Plant Water Budget

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

Monthly Watering Guide for Carrots

Carrots needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.

Month Carrots Needs Rainfall You Supplement Action
Jan 4.6" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 3.5" 4.2" 0" ✅ Rainfall sufficient
Apr 3.5" 3.6" 0" ✅ Rainfall sufficient
May 3.5" 3.9" 0" ✅ Rainfall sufficient
Jun 3.5" 4.9" 0" ✅ Rainfall sufficient
Jul 3.5" 5.9" 0" ✅ Rainfall sufficient
Aug 3.5" 5.4" 0" ✅ Rainfall sufficient
Sep 3.5" 4.2" 0" ✅ Rainfall sufficient
Oct 3.5" 3.4" 0.1" 💧 Light watering
Nov 3.5" 3.9" 0" ✅ Rainfall sufficient
Dec 4.3" 0" ❄️ Dormant

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

Carrots 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.

Carrots needs ~1,278 GDD — county provides 4,161 GDD Excellent fit

Carrots Planting Timeline — Marlboro County, SC

Carrots Planting Calendar

Activity When Date Range
Direct Sow March 9 Mar 9 – Mar 30
Harvest May 11 May 11 – Jun 15
Fall Sowing August 28 Aug 28 – Sep 11

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Direct Sow
April
May Harvest
June Harvest
July
August Fall Sowing
September Fall Sowing
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · Natural rainfall sufficient

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–6.8 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

228 days in Marlboro County

Growing Tips for Carrots in Marlboro County

Direct sow Carrots outdoors after March 23 in Marlboro County when soil has warmed and frost danger has passed.

With Marlboro County's clay soil (34% clay), work in 3-4 inches of compost before planting Carrots. Avoid tilling when soil is wet to prevent compaction.

Common pests for Carrots in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Sow seeds directly in loose, stone-free soil for straight roots. Keep soil moist until germination which can take 2-3 weeks. Thin seedlings to 2 inches apart.

Recommended Carrots Varieties for Marlboro County

Short, stout varieties that handle heavy soil — avoid long types like Imperator

Danvers Half Long Chantenay Oxheart

Companion Planting

Good Companions

Avoid Planting Near

  • Dill
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Carrots Seeds
Life Cycle Biennial
Pollination Cross-Pollinated (insects)
How to Collect Replant roots for 2nd year flowers. Harvest umbels when brown.
Storage Store airtight; viable 3 years at 35°F, under 50% humidity.

Isolate 1/2 mile from Queen Anne's Lace (wild carrot). Biennial — requires two seasons.

Frequently Asked Questions

When should I plant Carrots in Marlboro County, SC?

Marlboro County is in Zone 8a with an average last frost of March 23. Plan your Carrots planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marlboro County, SC?

Marlboro County, South Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 23 and first fall frost is November 6.

🌱

Your Marlboro County Garden Planner — Free

A 24-page printable planner built for Marlboro County (Zone 8a). 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 Marlboro County, SC. Local conditions may vary. Last updated: April 2026.

Sources & credits

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