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When to Plant Tomatillo in Union County, SC

Union County, South Carolina Zone 8a May

Union County, South Carolina gardeners: here's your May plan

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

Avg. last frost April 5
Avg. first frost October 31
Soil temp (4") 67°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Sow tomatillo in trays indoors

    Label every cell. You will absolutely forget which is which otherwise.

Coming up in June — start thinking about
  • First harvests: tomatillo

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Tomatillos are a Mexican staple that produces tart, green fruits enclosed in papery husks. They are essential for salsa verde and green sauces.

Union County, South Carolina is in USDA Zone 8a. The average last spring frost is April 5 and the first fall frost is October 31, giving you a growing season of approximately 209 days.

At an elevation of 478 feet, Union County receives approximately 53.3 inches of rainfall annually with predominantly clay loam soil. Summer highs average 91°F, providing good warmth for Tomatillo during the growing season. Clay soil retains moisture well for Tomatillo, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Tomatillo root diseases.

Union County, SC (Zone 8a) Long season
209 days
Last Spring Frost April 5
209 growing days
First Fall Frost October 31
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Union County Soil Profile

Soil Type

Clay Loam

Soil pH

5.7-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (65 days to spare)
Start indoors: Feb 6 Transplant: Apr 10 🍅 Harvest: Jun 12 – Aug 21
Recommended (50%) ✓ Fits season (62 days to spare)
Start indoors: Feb 15 Transplant: Apr 19 🍅 Harvest: Jun 21 – Aug 30
Safe Start (90%) ✓ Fits season (70 days to spare)
Start indoors: Feb 28 Transplant: May 2 🍅 Harvest: Jul 4 – Sep 12

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 Union County

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

Soil pH

Your soil pH (5.7–6.3) overlaps with Tomatillo's range (6.0–7.0), though not a perfect match.

Soil Texture

The clay loam soil in Union County is excellent for Tomatillo — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

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

How to Plant Tomatillo

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Tomatillo

4
successive plantings in your 209-day season

Sow every 6.9 weeks. Last sowing by Aug 07 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.1″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 54 gal / 100 sq ft

Monthly Watering Guide for Tomatillo

Tomatillo needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Tomatillo Needs Rainfall You Supplement Action
Jan 5.1" 0" ❄️ Dormant
Feb 3.9" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.8" 4.5" 0.3" 💧 Light watering
May 4.8" 3.8" 1" 💧 Light watering
Jun 4.8" 5.2" 0" ✅ Rainfall sufficient
Jul 4.8" 5.5" 0" ✅ Rainfall sufficient
Aug 4.8" 4.5" 0.3" 💧 Light watering
Sep 4.8" 4" 0.8" 💧 Light watering
Oct 4.8" 3.5" 1.3" 💧 Light watering
Nov 4.1" 0" ❄️ Dormant
Dec 4.8" 0" ❄️ Dormant

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

Tomatillo 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.

Tomatillo needs ~1,323 GDD — county provides 3,814 GDD Excellent fit

Tomatillo Planting Timeline — Union County, SC

Tomatillo Planting Calendar

Activity When Date Range
Start Indoors February 15 Feb 15 – Mar 1
Transplant Outdoors April 19 Apr 19 – May 3
Direct Sow April 12 Apr 12 – May 3
Harvest June 21 Jun 21 – Aug 30

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Only during dry spells

📅 Days to Maturity

60–85 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

209 days in Union County

Growing Tips for Tomatillo in Union County

Direct sow Tomatillo outdoors after April 05 in Union County when soil has warmed and frost danger has passed.

With Union County's clay soil (27% clay), work in 3-4 inches of compost before planting Tomatillo. Avoid tilling when soil is wet to prevent compaction.

Common pests for Tomatillo in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 6-8 weeks before last frost. Plant at least two plants for cross-pollination. Harvest when fruits fill the husk and it begins to split.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Dill

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Tomatillo in Union County, SC?

Union County is in Zone 8a with an average last frost of April 5. Plan your Tomatillo planting based on this frost date — see the calendar above for exact timing.

What planting zone is Union County, SC?

Union County, South Carolina is in USDA Hardiness Zone 8a. The average last spring frost is April 5 and first fall frost is October 31.

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Your Union County Garden Planner — Free

A 24-page printable planner built for Union 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 Union 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.