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When to Plant Mizuna in Webb County, TX

Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.

Webb County, Texas is in USDA Zone 9a. The average last spring frost is February 9 and the first fall frost is December 9, giving you a growing season of approximately 303 days.

At an elevation of 3,543 feet, Webb County receives approximately 50.9 inches of rainfall annually with predominantly loam soil. Summer highs average 95ยฐF, so Mizuna may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Mizuna root diseases.

Webb County, TX (Zone 9a) Year-round
303 days
Last Spring Frost February 9
303 growing days
First Fall Frost December 9

Webb County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (254 days to spare)
Start indoors: Dec 22 Transplant: Jan 19 🍅 Harvest: Feb 23 – Mar 23
Recommended (50%) ✓ Fits season (240 days to spare)
Start indoors: Jan 12 Transplant: Feb 9 🍅 Harvest: Mar 16 – Apr 13
Safe Start (90%) ✓ Fits season (228 days to spare)
Start indoors: Feb 5 Transplant: Mar 5 🍅 Harvest: Apr 9 – May 7

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 Webb County

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

Soil pH

Your soil pH (6.6โ€“7.7) overlaps with Mizuna's range (6.0โ€“7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Mizuna.

How to Plant Mizuna

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Mizuna

12
successive plantings in your 303-day season

Sow every 3.4 weeks. Last sowing by Oct 25 to harvest before frost.

For a dedicated fall crop, sow by Oct 14.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 964 gal / 100 sq ft
Drought risk

Water stress score is 6/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Mizuna

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

Month Mizuna Needs Rainfall You Supplement Action
Jan โ€” 1.3" 0" โ„๏ธ Dormant
Feb 4.3" 1.9" 2.4" ๐Ÿšฟ Regular watering
Mar 4.3" 2.8" 1.5" ๐Ÿ’ง Light watering
Apr 4.3" 5" 0" โœ… Rainfall sufficient
May 4.3" 8.3" 0" โœ… Rainfall sufficient
Jun 4.3" 7.6" 0" โœ… Rainfall sufficient
Jul 4.3" 5.9" 0" โœ… Rainfall sufficient
Aug 4.3" 6.4" 0" โœ… Rainfall sufficient
Sep 4.3" 5.2" 0" โœ… Rainfall sufficient
Oct 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Nov 4.3" 1.7" 2.6" ๐Ÿšฟ Regular watering
Dec 4.3" 1.5" 2.8" ๐Ÿšฟ Regular watering

Water needs are for active growing months only (Febโ€“Dec in Webb County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Mizuna 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.

Mizuna needs ~797 GDD — county provides 6,460 GDD Excellent fit

Mizuna Planting Timeline โ€” Webb County, TX

Mizuna Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 โ€“ Jan 26
Transplant Outdoors February 9 Feb 9 โ€“ Feb 23
Direct Sow January 19 Jan 19 โ€“ Feb 9
Harvest March 16 Mar 16 โ€“ Apr 13
Fall Sowing October 14 Oct 14 โ€“ Oct 28

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

1"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

30โ€“45 days

๐Ÿงช Soil pH

Needs 6โ€“7.5 ยท Your soil: acceptable

๐Ÿ—บ๏ธ USDA Zone

Zone 9a

๐Ÿ“† Growing Season

303 days in Webb County

Growing Tips for Mizuna in Webb County

Direct sow Mizuna outdoors after February 09 in Webb County when soil has warmed and frost danger has passed.

Your generous 304.0-day season in Webb County allows multiple plantings of Mizuna. Sow every 15.0 days for continuous harvest.

Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mizuna in Webb County, TX?

Webb County is in Zone 9a with an average last frost of February 9. Plan your Mizuna planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Webb County, TX?

Webb County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 9 and first fall frost is December 9.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Webb County gardeners in Zone 9a organize planting dates, track what's growing, and never miss a planting window.

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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 Webb County, TX. Local conditions may vary. Last updated: April 2026.