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

Bok choy is a Chinese cabbage variety with crisp white stalks and dark green leaves. It is a fast-growing cool-season crop ideal for stir-fries and soups.

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 Bok Choy 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 (139 days to spare)
Start indoors: Feb 21 Transplant: Mar 28 🍅 Harvest: May 9 – Jun 13
Recommended (50%) ✓ Fits season (136 days to spare)
Start indoors: Mar 1 Transplant: Apr 5 🍅 Harvest: May 17 – Jun 21
Safe Start (90%) ✓ Fits season (149 days to spare)
Start indoors: Mar 22 Transplant: Apr 26 🍅 Harvest: Jun 7 – Jul 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.

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,292 gal / 100 sq ft
Bok Choy needs ~950 GDD — county provides 4,047 GDD Excellent fit

Bok Choy Planting Timeline — St. Mary's County, MD

Bok Choy 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 17 May 17 – Jun 21

Plant 1" deep · 15" apart · Rows 24" 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

High — keep soil consistently moist

Days to Maturity

40–60 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 for best results. Keep soil consistently moist. Harvest whole heads or cut outer leaves for a cut-and-come-again approach.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Level Up Your Garden

Frequently Asked Questions

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

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