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When to Plant Sorrel in New Castle County, DE

New Castle County, Delaware Zone 7b May

May in the garden — New Castle County, Delaware

Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 6
Avg. first frost October 31
Soil temp (4") 67°F
Watering Moderate
Pest pressure Moderate
Daylight 14.2 hrs
  1. Sow sorrel in trays indoors

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Pick sorrel

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

To set up a strong June, finish these tasks
  • First harvests: sorrel

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Sorrel is a perennial herb with tangy, lemon-flavored arrow-shaped leaves. It is one of the first greens to emerge in spring and is used in soups and salads.

New Castle County, Delaware is in USDA Zone 7b. The average last spring frost is April 6 and the first fall frost is October 31, giving you a growing season of approximately 208 days.

At an elevation of 415 feet, New Castle County receives approximately 38.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Sorrel during the growing season.

New Castle County, DE (Zone 7b) Long season
208 days
Last Spring Frost April 6
208 growing days
First Fall Frost October 31
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New Castle County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (113 days to spare)
Start indoors: Feb 21 Transplant: Mar 21 🍅 Harvest: May 2 – Jul 4
Recommended (50%) ✓ Fits season (110 days to spare)
Start indoors: Mar 2 Transplant: Mar 30 🍅 Harvest: May 11 – Jul 13
Safe Start (90%) ✓ Fits season (98 days to spare)
Start indoors: Mar 26 Transplant: Apr 23 🍅 Harvest: Jun 4 – Aug 6

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 New Castle County

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

Soil pH

Your soil pH (5.2–7.1) overlaps with Sorrel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Sorrel.

How to Plant Sorrel

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 Sorrel

6
successive plantings in your 208-day season

Sow every 4.6 weeks. Last sowing by Sep 01 to harvest before frost.

For a dedicated fall crop, sow by Aug 22.

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 427 gal / 100 sq ft

Monthly Watering Guide for Sorrel

Sorrel needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Sorrel Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.3" 1" 💧 Light watering
Jun 4.3" 3.3" 1" 💧 Light watering
Jul 4.3" 4.1" 0.2" 💧 Light watering
Aug 4.3" 3.2" 1.1" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 3.2" 1.1" 💧 Light watering
Nov 3.4" 0" ❄️ Dormant
Dec 2.9" 0" ❄️ Dormant

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

Sorrel 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.

Sorrel needs ~838 GDD — county provides 3,484 GDD Excellent fit

Sorrel Planting Timeline — New Castle County, DE

Sorrel Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors March 30 Mar 30 – Apr 13
Direct Sow March 23 Mar 23 – Apr 13
Harvest May 11 May 11 – Jul 13
Fall Sowing August 22 Aug 22 – Sep 5

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

Month-by-Month Timeline

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

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 7b

📆 Growing Season

208 days in New Castle County

Growing Tips for Sorrel in New Castle County

Direct sow Sorrel outdoors after April 06 in New Castle County when soil has warmed and frost danger has passed.

Your generous 208.0-day season in New Castle County allows multiple plantings of Sorrel. Sow every 20.0 days for continuous harvest.

General growing tips

Direct sow in early spring or fall. Remove flower stalks promptly to encourage leaf production. Divide clumps every 3-4 years. Young leaves have the best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sorrel in New Castle County, DE?

New Castle County is in Zone 7b with an average last frost of April 6. Plan your Sorrel planting based on this frost date — see the calendar above for exact timing.

What planting zone is New Castle County, DE?

New Castle County, Delaware is in USDA Hardiness Zone 7b. The average last spring frost is April 6 and first fall frost is October 31.

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Your New Castle County Garden Planner — Free

A 24-page printable planner built for New Castle 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 New Castle County, DE. 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.