Blog

When to Plant Sorrel in Rock County, WI

Rock County, Wisconsin Zone 5a April

Your April planting checklist for Rock County, Wisconsin

We've pulled the most time-sensitive tasks for Rock County, Wisconsin this April and put them front and centre. Tackle them in order.

Avg. last frost April 26
Avg. first frost October 13
Soil temp (4") 47°F
Watering Moderate
Pest pressure Low
Daylight 13.2 hrs
  1. Transplant sorrel outside

    Your last frost (April 26) has passed. These warm-season crops can handle outdoor soil now.

  2. Seed sorrel outdoors

    These tolerate cool soil, so you're not gambling by sowing now.

Coming up in May — start thinking about
  • Starting indoors: sorrel
  • First harvests: sorrel

Instant PDF download. No spam, unsubscribe any time.

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.

Rock County, Wisconsin is in USDA Zone 5a. The average last spring frost is April 26 and the first fall frost is October 13, giving you a growing season of approximately 170 days.

At an elevation of 710 feet, Rock County receives approximately 30.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Sorrel during the growing season.

Rock County, WI (Zone 5a) Moderate season
170 days
Last Spring Frost April 26
170 growing days
First Fall Frost October 13

Rock County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (72 days to spare)
Start indoors: Mar 17 Transplant: Apr 14 🍅 Harvest: May 26 – Jul 28
Recommended (50%) ✓ Fits season (72 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🍅 Harvest: May 31 – Aug 2
Safe Start (90%) ✓ Fits season (71 days to spare)
Start indoors: Apr 6 Transplant: May 4 🍅 Harvest: Jun 15 – Aug 17

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 Rock County

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

Soil pH

Your soil pH (6.2–7.1) overlaps with Sorrel's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — Sorrel will thrive.

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

5
successive plantings in your 170-day season

Sow every 4.6 weeks. Last sowing by Aug 14 to harvest before frost.

For a dedicated fall crop, sow by Aug 04.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 452 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.3" 3.3" 1" 💧 Light watering
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 3.8" 0.5" 💧 Light watering
Jul 4.3" 3.2" 1.1" 💧 Light watering
Aug 4.3" 3" 1.3" 💧 Light watering
Sep 4.3" 2.8" 1.5" 💧 Light watering
Oct 4.3" 2.6" 1.7" 💧 Light watering
Nov 2.4" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Rock 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 ~725 GDD — county provides 2,465 GDD Excellent fit

Sorrel Planting Timeline — Rock County, WI

Sorrel Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors April 19 Apr 19 – May 3
Direct Sow April 12 Apr 12 – May 3
Harvest May 31 May 31 – Aug 2
Fall Sowing August 4 Aug 4 – Aug 18

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

Month-by-Month Timeline

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

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 5a

📆 Growing Season

170 days in Rock County

Growing Tips for Sorrel in Rock County

Direct sow Sorrel outdoors after April 26 in Rock County when soil has warmed and frost danger has passed.

Your generous 170.0-day season in Rock 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 Rock County, WI?

Rock County is in Zone 5a with an average last frost of April 26. Plan your Sorrel planting based on this frost date — see the calendar above for exact timing.

What planting zone is Rock County, WI?

Rock County, Wisconsin is in USDA Hardiness Zone 5a. The average last spring frost is April 26 and first fall frost is October 13.

🌱

Your Rock County Garden Planner — Free

A 24-page printable planner built for Rock County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Rock County, WI. Local conditions may vary. Last updated: April 2026.

Sources & credits

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