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When to Plant Yam in Beaufort County, SC

Beaufort County, South Carolina Zone 9a May

This month in Beaufort County, South Carolina

Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost March 13
Avg. first frost November 15
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.7 hrs

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True yams are tropical tubers distinct from sweet potatoes, producing large starchy roots that can weigh several pounds. They are a staple food in tropical regions worldwide.

Beaufort County, South Carolina is in USDA Zone 9a. The average last spring frost is March 13 and the first fall frost is November 15, giving you a growing season of approximately 247 days.

At an elevation of 288 feet, Beaufort County receives approximately 56.5 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95°F, so Yam may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Yam will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Yam root diseases.

Beaufort County, SC (Zone 9a) Long season
247 days
Last Spring Frost March 13
247 growing days
First Fall Frost November 15
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Beaufort County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.9-6.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (304 days to spare)
Start indoors: Jan 21 Transplant: Mar 11 🍅 Harvest: Sep 9 – Jan 6
Recommended (50%) ✓ Fits season (304 days to spare)
Start indoors: Jan 30 Transplant: Mar 20 🍅 Harvest: Sep 18 – Jan 15
Safe Start (90%) ✓ Fits season (297 days to spare)
Start indoors: Feb 26 Transplant: Apr 16 🍅 Harvest: Oct 15 – Feb 11

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 Beaufort County

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

Soil pH

Your soil pH (4.9–6.1) overlaps with Yam's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Yam.

Organic Matter

Organic matter is low (1.8%). Add 2-3 inches of compost before planting Yam.

How to Plant Yam

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

Plant Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Yam

Yam needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Yam Needs Rainfall You Supplement Action
Jan 4.6" 0" ❄️ Dormant
Feb 4.8" 0" ❄️ Dormant
Mar 4.3" 5" 0" ✅ Rainfall sufficient
Apr 4.3" 4.6" 0" ✅ Rainfall sufficient
May 4.3" 5" 0" ✅ Rainfall sufficient
Jun 4.3" 4.9" 0" ✅ Rainfall sufficient
Jul 4.3" 5.3" 0" ✅ Rainfall sufficient
Aug 4.3" 5.4" 0" ✅ Rainfall sufficient
Sep 4.3" 4.8" 0" ✅ Rainfall sufficient
Oct 4.3" 4.1" 0.2" 💧 Light watering
Nov 4.3" 4" 0.3" 💧 Light watering
Dec 4" 0" ❄️ Dormant

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

Yam 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.

Yam needs ~5,419 GDD — county provides 5,248 GDD Tight fit

Yam Planting Timeline — Beaufort County, SC

Yam Planting Calendar

Activity When Date Range
Start Indoors January 30 Jan 30 – Feb 13
Transplant Outdoors March 20 Mar 20 – Apr 3
Direct Sow March 13 Mar 13 – Apr 3
Harvest September 18 Sep 18 – Jan 15

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

180–330 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

247 days in Beaufort County

Growing Tips for Yam in Beaufort County

Direct sow Yam outdoors after March 13 in Beaufort County when soil has warmed and frost danger has passed.

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

Your 247.0-day growing season in Beaufort County is tight for Yam (180.0-330.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant tuber pieces in mounds of loose, rich soil. Provide sturdy trellising for climbing vines. Yams require a long, warm growing season of 8-11 months. Harvest when vines die back.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Yam in Beaufort County, SC?

Beaufort County is in Zone 9a with an average last frost of March 13. Plan your Yam planting based on this frost date — see the calendar above for exact timing.

What planting zone is Beaufort County, SC?

Beaufort County, South Carolina is in USDA Hardiness Zone 9a. The average last spring frost is March 13 and first fall frost is November 15.

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Your Beaufort County Garden Planner — Free

A 24-page printable planner built for Beaufort County (Zone 9a). 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 Beaufort 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.