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When to Plant Komatsuna in Allendale County, SC

Allendale County, South Carolina Zone 8a April

Your April game plan for Allendale County, South Carolina

If you only do a handful of things in the garden this April, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 21
Avg. first frost November 9
Soil temp (4") 63°F
Watering Low
Pest pressure High
Daylight 12.8 hrs
  1. Indoor seed-starting week for komatsuna

    These need a head start before your last frost (March 21). Sow into cells now so you're ready to transplant in a few weeks.

  2. Harvest komatsuna as they ripen

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

Before May arrives, get these ready
  • First harvests: komatsuna

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Komatsuna (Japanese mustard spinach) is a versatile Asian green with glossy, dark leaves and a mild, sweet flavor. It is extremely cold-hardy and heat-tolerant.

Allendale County, South Carolina is in USDA Zone 8a. The average last spring frost is March 21 and the first fall frost is November 9, giving you a growing season of approximately 233 days.

At an elevation of 451 feet, Allendale County receives approximately 60.6 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 91°F, providing good warmth for Komatsuna during the growing season. Sandy soil warms quickly in spring — great for early planting — but Komatsuna will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Komatsuna root diseases.

Allendale County, SC (Zone 8a) Long season
233 days
Last Spring Frost March 21
233 growing days
First Fall Frost November 9
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Allendale County Soil Profile

Soil Type

Sandy Loam

Soil pH

4.8-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (165 days to spare)
Start indoors: Feb 4 Transplant: Mar 11 🍅 Harvest: Apr 15 – May 20
Recommended (50%) ✓ Fits season (163 days to spare)
Start indoors: Feb 14 Transplant: Mar 21 🍅 Harvest: Apr 25 – May 30
Safe Start (90%) ✓ Fits season (164 days to spare)
Start indoors: Mar 5 Transplant: Apr 9 🍅 Harvest: May 14 – Jun 18

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 Allendale County

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

Soil pH

Your soil pH (4.8–6.3) is more acidic than Komatsuna prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Komatsuna.

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting Komatsuna.

How to Plant Komatsuna

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 Komatsuna

8
successive plantings in your 233-day season

Sow every 4 weeks. Last sowing by Sep 20 to harvest before frost.

For a dedicated fall crop, sow by Aug 31.

Plant Water Budget

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

Monthly Watering Guide for Komatsuna

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

Month Komatsuna Needs Rainfall You Supplement Action
Jan 4.3" 0" ❄️ Dormant
Feb 5.3" 0" ❄️ Dormant
Mar 4.3" 5.4" 0" ✅ Rainfall sufficient
Apr 4.3" 4.8" 0" ✅ Rainfall sufficient
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 6" 0" ✅ Rainfall sufficient
Jul 4.3" 5.9" 0" ✅ Rainfall sufficient
Aug 4.3" 6.5" 0" ✅ Rainfall sufficient
Sep 4.3" 4.5" 0" ✅ Rainfall sufficient
Oct 4.3" 3.8" 0.5" 💧 Light watering
Nov 4.3" 4.7" 0" ✅ Rainfall sufficient
Dec 4.8" 0" ❄️ Dormant

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

Komatsuna 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.

Komatsuna needs ~776 GDD — county provides 4,252 GDD Excellent fit

Komatsuna Planting Timeline — Allendale County, SC

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors February 14 Feb 14 – Feb 28
Transplant Outdoors March 21 Mar 21 – Apr 4
Direct Sow March 7 Mar 7 – Mar 28
Harvest April 25 Apr 25 – May 30
Fall Sowing August 31 Aug 31 – Sep 14

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 8a

📆 Growing Season

233 days in Allendale County

Growing Tips for Komatsuna in Allendale County

Direct sow Komatsuna outdoors after March 21 in Allendale County when soil has warmed and frost danger has passed.

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

Your generous 233.0-day season in Allendale County allows multiple plantings of Komatsuna. Sow every 17.0 days for continuous harvest.

Common pests for Komatsuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. One of the most forgiving Asian greens for all seasons. Harvest outer leaves or cut whole plants. Excellent for stir-fries, soups, or salads.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Komatsuna in Allendale County, SC?

Allendale County is in Zone 8a with an average last frost of March 21. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Allendale County, SC?

Allendale County, South Carolina is in USDA Hardiness Zone 8a. The average last spring frost is March 21 and first fall frost is November 9.

🌱

Your Allendale County Garden Planner — Free

A 24-page printable planner built for Allendale 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 Allendale 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.