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

Tatsoi is a compact Asian green forming beautiful rosettes of dark, spoon-shaped leaves with a mild mustard flavor. It is extremely cold-hardy and versatile.

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 Tatsoi 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 (146 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: May 2 – Jun 6
Recommended (50%) ✓ Fits season (143 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: May 10 – Jun 14
Safe Start (90%) ✓ Fits season (156 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: May 31 – Jul 5

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
Tatsoi needs ~808 GDD — county provides 4,047 GDD Excellent fit

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

Tatsoi 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 10 May 10 – Jun 14

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

Partial Shade (3-6 hours)

Water

Moderate — regular watering

Days to Maturity

35–50 days

Soil pH

6 – 7.5

USDA Zone

Zone 7a

Growing Season

213 days

Growing Tips for St. Mary's County

Direct sow in spring or fall. Tatsoi tolerates frost down to 15F. Harvest outer leaves or cut whole rosettes. Excellent in salads, stir-fries, or lightly wilted.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

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

St. Mary's County is in Zone 7a with an average last frost of April 5. Plan your Tatsoi 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.