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When to Plant Komatsuna in Brazoria County, TX

Brazoria County, Texas Zone 9b May

What to do in May

Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost February 12
Avg. first frost December 8
Soil temp (4") 78°F
Watering Low
Pest pressure High
Daylight 13.5 hrs

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Komatsuna (Japanese mustard spinach) is a versatile Asian green with glossy, dark leaves and a mild, sweet flavor. It is extremely cold-hardy and heat-tolerant.

Brazoria County, Texas is in USDA Zone 9b. The average last spring frost is February 12 and the first fall frost is December 8, giving you a growing season of approximately 299 days.

At an elevation of 348 feet, Brazoria County receives approximately 71.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 102°F, so Komatsuna may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Komatsuna will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Komatsuna root diseases.

Brazoria County, TX (Zone 9b) Year-round
299 days
Last Spring Frost February 12
299 growing days
First Fall Frost December 8

Brazoria County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (245 days to spare)
Start indoors: Dec 25 Transplant: Jan 22 🍅 Harvest: Feb 26 – Apr 2
Recommended (50%) ✓ Fits season (229 days to spare)
Start indoors: Jan 15 Transplant: Feb 12 🍅 Harvest: Mar 19 – Apr 23
Safe Start (90%) ✓ Fits season (220 days to spare)
Start indoors: Feb 9 Transplant: Mar 9 🍅 Harvest: Apr 13 – May 18

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 Brazoria County

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

Soil pH

Your soil pH (5.5–6.3) is more acidic than Komatsuna prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

Sandy soil in Brazoria County warms quickly in spring but drains fast. Komatsuna will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is moderate (2.0%). Annual compost additions will help Komatsuna.

How to Plant Komatsuna

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 Komatsuna

10
successive plantings in your 299-day season

Sow every 4 weeks. Last sowing by Oct 19 to harvest before frost.

For a dedicated fall crop, sow by Oct 13.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Komatsuna

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

Month Komatsuna Needs Rainfall You Supplement Action
Jan 1.7" 0" ❄️ Dormant
Feb 4.3" 2.5" 1.8" 💧 Light watering
Mar 4.3" 4.3" 0" ✅ Rainfall sufficient
Apr 4.3" 8.4" 0" ✅ Rainfall sufficient
May 4.3" 11.2" 0" ✅ Rainfall sufficient
Jun 4.3" 11.3" 0" ✅ Rainfall sufficient
Jul 4.3" 8" 0" ✅ Rainfall sufficient
Aug 4.3" 8.7" 0" ✅ Rainfall sufficient
Sep 4.3" 6.6" 0" ✅ Rainfall sufficient
Oct 4.3" 5.1" 0" ✅ Rainfall sufficient
Nov 4.3" 2.5" 1.8" 💧 Light watering
Dec 4.3" 1.6" 2.7" 🚿 Regular watering

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

Komatsuna 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.

Komatsuna needs ~1,126 GDD — county provides 7,950 GDD Excellent fit

Komatsuna Planting Timeline — Brazoria County, TX

Komatsuna Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors February 12 Feb 12 – Feb 26
Direct Sow January 22 Jan 22 – Feb 12
Harvest March 19 Mar 19 – Apr 23
Fall Sowing October 13 Oct 13 – Oct 27

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

35–50 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

299 days in Brazoria County

Growing Tips for Komatsuna in Brazoria County

Direct sow Komatsuna outdoors after February 12 in Brazoria County when soil has warmed and frost danger has passed.

Sandy soil in Brazoria County dries quickly — mulch Komatsuna with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 102°F in Brazoria County, provide afternoon shade for Komatsuna and water deeply in the morning.

Your generous 300.0-day season in Brazoria County allows multiple plantings of Komatsuna. Sow every 17.0 days for continuous harvest.

Common pests for Komatsuna 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. One of the most forgiving Asian greens for all seasons. Harvest outer leaves or cut whole plants. Excellent for stir-fries, soups, or salads.

Companion Planting

Good Companions

Avoid Planting Near

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Komatsuna in Brazoria County, TX?

Brazoria County is in Zone 9b with an average last frost of February 12. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.

What planting zone is Brazoria County, TX?

Brazoria County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 12 and first fall frost is December 8.

🌱

Your Brazoria County Garden Planner — Free

A 24-page printable planner built for Brazoria County (Zone 9b). 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 Brazoria County, TX. 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.