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When to Plant Sorrel in Knox County, TX

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.

Knox County, Texas is in USDA Zone 7b. The average last spring frost is March 24 and the first fall frost is November 12, giving you a growing season of approximately 233 days.

At an elevation of 1,847 feet, Knox County receives approximately 51.2 inches of rainfall annually with predominantly loam soil. Summer highs average 93ยฐF, providing good warmth for Sorrel during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sorrel root diseases.

Knox County, TX (Zone 7b) Long season
233 days
Last Spring Frost March 24
233 growing days
First Fall Frost November 12

Knox County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (132 days to spare)
Start indoors: Feb 10 Transplant: Mar 10 🍅 Harvest: Apr 21 – Jun 23
Recommended (50%) ✓ Fits season (135 days to spare)
Start indoors: Feb 17 Transplant: Mar 17 🍅 Harvest: Apr 28 – Jun 30
Safe Start (90%) ✓ Fits season (128 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: May 18 – Jul 20

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 Knox County

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

Soil pH

Your soil pH (6.4โ€“7.2) overlaps with Sorrel's range (5.5โ€“7.0), though not a perfect match.

Soil Texture

The loam soil in Knox County is excellent for Sorrel โ€” good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting 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

7
successive plantings in your 233-day season

Sow every 4.6 weeks. Last sowing by Sep 13 to harvest before frost.

For a dedicated fall crop, sow by Sep 03.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 160 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 โ€” 1.3" 0" โ„๏ธ Dormant
Feb โ€” 2.1" 0" โ„๏ธ Dormant
Mar 4.3" 3.2" 1.1" ๐Ÿ’ง Light watering
Apr 4.3" 6.4" 0" โœ… Rainfall sufficient
May 4.3" 6.7" 0" โœ… Rainfall sufficient
Jun 4.3" 7.3" 0" โœ… Rainfall sufficient
Jul 4.3" 6.5" 0" โœ… Rainfall sufficient
Aug 4.3" 5.9" 0" โœ… Rainfall sufficient
Sep 4.3" 5.4" 0" โœ… Rainfall sufficient
Oct 4.3" 3.3" 1" ๐Ÿ’ง Light watering
Nov 4.3" 1.8" 2.5" ๐Ÿšฟ Regular watering
Dec โ€” 1.3" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Marโ€“Nov in Knox County). Supplement amounts are based on average rainfall โ€” 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" โ€” every day above 50ยฐF 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 ~988 GDD — county provides 4,601 GDD Excellent fit

Sorrel Planting Timeline โ€” Knox County, TX

Sorrel Planting Calendar

Activity When Date Range
Start Indoors February 17 Feb 17 โ€“ Mar 3
Transplant Outdoors March 17 Mar 17 โ€“ Mar 31
Direct Sow March 10 Mar 10 โ€“ Mar 31
Harvest April 28 Apr 28 โ€“ Jun 30
Fall Sowing September 3 Sep 3 โ€“ Sep 17

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

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท Only during dry spells

๐Ÿ“… Days to Maturity

40โ€“60 days

๐Ÿงช Soil pH

Needs 5.5โ€“7 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 7b

๐Ÿ“† Growing Season

233 days in Knox County

Growing Tips for Sorrel in Knox County

Direct sow Sorrel outdoors after March 24 in Knox County when soil has warmed and frost danger has passed.

Your generous 233.0-day season in Knox 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 Knox County, TX?

Knox County is in Zone 7b with an average last frost of March 24. Plan your Sorrel planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Knox County, TX?

Knox County, Texas is in USDA Hardiness Zone 7b. The average last spring frost is March 24 and first fall frost is November 12.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Knox County gardeners in Zone 7b organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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