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When to plant Corn in Calvert County, MD

The best window to plant Corn in Calvert County, is April 6–April 27, when soil warms to 50°F. Last frost typically hits March 30; first frost November 10.

When to Plant Corn in Calvert County, MD

Corn
Calvert County, Maryland Zone 7b June

June in Calvert County, Maryland — your action list

Your Calvert County, Maryland garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost March 30
Avg. first frost November 10
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 14.7 hrs
  1. Start harvesting corn

    If you can't use it all right away, check the food-preservation section of your planner.

July prep starts now
  • First harvests: corn

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Corn is a warm-season grass grown for its sweet ears, which are best eaten soon after harvest. It is wind-pollinated and must be planted in blocks for good kernel fill.

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 Corn 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

Calvert County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.9

Drainage

Well Drained

Corn Planting Risk Windows

Early Start (70% safe) ✓ Fits season (103 days to spare)
Transplant: Mar 26 🍅 Harvest: May 28 – Jul 23
Recommended (50%) ✓ Fits season (106 days to spare)
Transplant: Mar 30 🍅 Harvest: Jun 1 – Jul 27
Safe Start (90%) ✓ Fits season (117 days to spare)
Transplant: Apr 17 🍅 Harvest: Jun 19 – Aug 14

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 Corn's growing requirements.

Soil pH

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

Soil Texture

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

Organic Matter

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

How to Plant Corn

1"
Planting Depth
12"
Between Plants
36"
Between Rows

Succession Planting Corn

4
successive plantings in your 225-day season

Sow every 6.9 weeks. Last sowing by Aug 02 to harvest before frost.

Corn Water Budget

Plant needs
1.5″/week
Rainfall provides
0.9″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 1,281 gal / 100 sq ft

Monthly Watering Guide for Corn

Corn needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Corn Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 6.5" 3.6" 2.9" 💧 Light watering
Apr 6.5" 3.8" 2.7" 💧 Light watering
May 6.5" 4.1" 2.4" 💧 Light watering
Jun 6.5" 4.5" 2" 💧 Light watering
Jul 6.5" 5.1" 1.4" 💧 Light watering
Aug 6.5" 3.9" 2.6" 💧 Light watering
Sep 6.5" 4" 2.5" 💧 Light watering
Oct 6.5" 4.2" 2.3" 💧 Light watering
Nov 6.5" 3.2" 3.3" 🚿 Regular watering
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.

Corn 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.

Corn needs ~1,400 GDD — county provides 3,937 GDD Excellent fit

Corn Planting Timeline — Calvert County, MD

Corn Planting Calendar

Activity When Date Range
Direct Sow April 6 Apr 6 – Apr 27
Harvest June 8 Jun 8 – Aug 3

Plant 1" deep · 12" apart · Rows 36" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Direct Sow
May
June Harvest
July Harvest
August Harvest
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · 1-2 times/week

📅 Days to Maturity

60–100 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

225 days in Calvert County

Growing Tips for Corn in Calvert County

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

Common pests for Corn in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant in blocks of at least 4 rows rather than single rows for proper pollination. Direct sow after soil reaches 60F. Side-dress with nitrogen when plants are knee-high.

Companion Planting

Good Companions

Avoid Planting Near

  • Tomatoes
  • Celery

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Corn in Calvert County, MD?

Calvert County is in Zone 7b with an average last frost of March 30. Plan your Corn 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.

When should I plant Corn in Calvert County, MD?

In Calvert County, MD, plant Corn after the last frost (around March 30) and before the first frost (around November 10). Best results when soil holds above 50°F.

What growing zone is Calvert County, MD for Corn?

Calvert County sits in USDA Zone 7b. Corn grows reliably in zones 3a through 11b, so it's a good fit here.

Can Corn grow in Calvert County's climate?

Yes — Corn grows well in Calvert County's temperate climate. Calvert County averages a 225-day frost-free season, with last frost around March 30 and first frost around November 10.

🌱

Your Calvert County Garden Planner — Free

A 22-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: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.