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When to Plant Scallions in St. Mary's County, MD

Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.

St. Mary's County, Maryland is in USDA Zone 7a. The average last spring frost is April 5 and the first fall frost is November 4, giving you a growing season of approximately 213 days.

At an elevation of 156 feet, St. Mary's County receives approximately 41.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 92°F, providing good warmth for Scallions during the growing season.

St. Mary's County, MD (Zone 7a) Long season
213 days
Last Spring Frost April 5
213 growing days
First Fall Frost November 4

St. Mary's County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (132 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: May 23 – Jun 20
Recommended (50%) ✓ Fits season (129 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: May 31 – Jun 28
Safe Start (90%) ✓ Fits season (142 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 21 – Jul 19

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 344 gal / 100 sq ft
Scallions needs ~1,140 GDD — county provides 4,047 GDD Excellent fit

Scallions Planting Timeline — St. Mary's County, MD

Scallions Planting Calendar

Activity When Date Range
Start Indoors March 1 Mar 1 – Mar 15
Transplant Outdoors April 5 Apr 5 – Apr 19
Direct Sow March 22 Mar 22 – Apr 12
Fall Sowing August 26 Aug 26 – Sep 9
Harvest May 31 May 31 – Jun 28

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Full Sun (6-8+ hours)

Water

Moderate — regular watering

Days to Maturity

50–70 days

Soil pH

6 – 7

USDA Zone

Zone 7a

Growing Season

213 days

Growing Tips for St. Mary's County

Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

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Frequently Asked Questions

When should I plant Scallions in St. Mary's County, MD?

St. Mary's County is in Zone 7a with an average last frost of April 5. Plan your Scallions planting based on this frost date — see the calendar above for exact timing.

What planting zone is St. Mary's County, MD?

St. Mary's County, Maryland is in USDA Hardiness Zone 7a. The average last spring frost is April 5 and first fall frost is November 4.

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Plan Your Garden with Confidence

Get our free Garden Planner — designed to help St. Mary's County gardeners in Zone 7a organize planting dates, track what's growing, and never miss a planting window.

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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 St. Mary's County, MD. Local conditions may vary. Last updated: April 2026.