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When to Plant Cilantro in Calvert County, MD

Calvert County, Maryland Zone 7b May

May to-do list for Calvert County, Maryland

We've pulled the most time-sensitive tasks for Calvert County, Maryland this May and put them front and centre. Tackle them in order.

Avg. last frost March 30
Avg. first frost November 10
Soil temp (4") 68°F
Watering Low
Pest pressure Moderate
Daylight 14.1 hrs
  1. Sow cilantro in trays indoors

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

  2. Start harvesting cilantro

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this May that'll pay off in June
  • First harvests: cilantro

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Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

Calvert County, Maryland is in USDA Zone 7b. The average last spring frost is March 30 and the first fall frost is November 10, giving you a growing season of approximately 225 days.

At an elevation of 539 feet, Calvert County receives approximately 46.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Cilantro during the growing season.

Calvert County, MD (Zone 7b) Long season
225 days
Last Spring Frost March 30
225 growing days
First Fall Frost November 10
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Calvert 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 (124 days to spare)
Start indoors: Feb 19 Transplant: Mar 19 🍅 Harvest: Apr 30 – Jul 2
Recommended (50%) ✓ Fits season (127 days to spare)
Start indoors: Feb 23 Transplant: Mar 23 🍅 Harvest: May 4 – Jul 6
Safe Start (90%) ✓ Fits season (138 days to spare)
Start indoors: Mar 13 Transplant: Apr 10 🍅 Harvest: May 22 – Jul 24

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 Calvert County

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

Soil pH

Your soil pH (5.5–6.9) overlaps with Cilantro's range (6.0–7.0), though not a perfect match.

Soil Texture

The silt loam soil in Calvert County is excellent for Cilantro — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.7%). Annual compost additions will help Cilantro.

How to Plant Cilantro

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Cilantro

6
successive plantings in your 225-day season

Sow every 4.6 weeks. Last sowing by Sep 11 to harvest before frost.

For a dedicated fall crop, sow by Sep 01.

Plant Water Budget

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

Monthly Watering Guide for Cilantro

Cilantro needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cilantro Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 2.2" 3.6" 0" ✅ Rainfall sufficient
Apr 2.2" 3.8" 0" ✅ Rainfall sufficient
May 2.2" 4.1" 0" ✅ Rainfall sufficient
Jun 2.2" 4.5" 0" ✅ Rainfall sufficient
Jul 2.2" 5.1" 0" ✅ Rainfall sufficient
Aug 2.2" 3.9" 0" ✅ Rainfall sufficient
Sep 2.2" 4" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 2.2" 3.2" 0" ✅ Rainfall sufficient
Dec 3.1" 0" ❄️ Dormant

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

Cilantro 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.

Cilantro needs ~875 GDD — county provides 3,937 GDD Excellent fit

Cilantro Planting Timeline — Calvert County, MD

Cilantro Planting Calendar

Activity When Date Range
Start Indoors February 23 Feb 23 – Mar 9
Transplant Outdoors March 23 Mar 23 – Apr 6
Direct Sow March 16 Mar 16 – Apr 6
Harvest May 4 May 4 – Jul 6
Fall Sowing September 1 Sep 1 – Sep 15

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

225 days in Calvert County

Growing Tips for Cilantro in Calvert County

Direct sow Cilantro outdoors after March 30 in Calvert County when soil has warmed and frost danger has passed.

Your generous 225.0-day season in Calvert County allows multiple plantings of Cilantro. Sow every 20.0 days for continuous harvest.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Calvert County, MD?

Calvert County is in Zone 7b with an average last frost of March 30. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.

What planting zone is Calvert County, MD?

Calvert County, Maryland is in USDA Hardiness Zone 7b. The average last spring frost is March 30 and first fall frost is November 10.

🌱

Your Calvert County Garden Planner — Free

A 24-page printable planner built for Calvert County (Zone 7b). 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 Calvert County, MD. 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.