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When to Plant Microgreens in Williamson County, TX

Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.

Williamson County, Texas is in USDA Zone 8b. The average last spring frost is March 5 and the first fall frost is November 22, giving you a growing season of approximately 262 days.

At an elevation of 1,023 feet, Williamson County receives approximately 53.3 inches of rainfall annually with predominantly clay soil. Summer highs average 94ยฐF, providing good warmth for Microgreens during the growing season. Clay soil retains moisture well for Microgreens, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Microgreens root diseases.

Williamson County, TX (Zone 8b) Long season
262 days
Last Spring Frost March 5
262 growing days
First Fall Frost November 22

Williamson County Soil Profile

Soil Type

Clay

Soil pH

7.1-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (229 days to spare)
Start indoors: Jan 17 Transplant: Feb 21 🍅 Harvest: Feb 28 – Mar 28
Recommended (50%) ✓ Fits season (227 days to spare)
Start indoors: Jan 29 Transplant: Mar 5 🍅 Harvest: Mar 12 – Apr 9
Safe Start (90%) ✓ Fits season (215 days to spare)
Start indoors: Mar 2 Transplant: Apr 6 🍅 Harvest: Apr 13 – May 11

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 Williamson County

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

Soil pH

Your soil pH (7.1โ€“7.8) is more alkaline than Microgreens prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (46% clay) in Williamson County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Drainage

Drainage is adequate for Microgreens.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Microgreens.

How to Plant Microgreens

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Microgreens

52
successive plantings in your 262-day season

Sow every 0.7 weeks. Last sowing by Nov 01 to harvest before frost.

For a dedicated fall crop, sow by Sep 13.

Plant Water Budget

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

Monthly Watering Guide for Microgreens

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

Month Microgreens Needs Rainfall You Supplement Action
Jan โ€” 1.4" 0" โ„๏ธ Dormant
Feb โ€” 2" 0" โ„๏ธ Dormant
Mar 4.3" 3.4" 0.9" ๐Ÿ’ง Light watering
Apr 4.3" 6.5" 0" โœ… Rainfall sufficient
May 4.3" 7.7" 0" โœ… Rainfall sufficient
Jun 4.3" 7.6" 0" โœ… Rainfall sufficient
Jul 4.3" 6.6" 0" โœ… Rainfall sufficient
Aug 4.3" 6.1" 0" โœ… Rainfall sufficient
Sep 4.3" 5.4" 0" โœ… Rainfall sufficient
Oct 4.3" 3.7" 0.6" ๐Ÿ’ง Light watering
Nov 4.3" 1.7" 2.6" ๐Ÿšฟ Regular watering
Dec โ€” 1.3" 0" โ„๏ธ Dormant

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

Microgreens 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.

Microgreens needs ~287 GDD — county provides 5,371 GDD Excellent fit

Microgreens Planting Timeline โ€” Williamson County, TX

Microgreens Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 โ€“ Feb 12
Transplant Outdoors March 5 Mar 5 โ€“ Mar 19
Direct Sow February 19 Feb 19 โ€“ Mar 12
Harvest March 12 Mar 12 โ€“ Apr 9
Fall Sowing September 13 Sep 13 โ€“ Sep 27

Plant 0.5" deep ยท 2" apart ยท Rows 6" apart

Month-by-Month Timeline

MonthActivities
January Start Indoors
February Start Indoors Direct Sow
March Transplant Outdoors Direct Sow Harvest
April Harvest
May โ€”
June โ€”
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 Natural rainfall sufficient

๐Ÿ“… Days to Maturity

7โ€“21 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 8b

๐Ÿ“† Growing Season

262 days in Williamson County

Growing Tips for Microgreens in Williamson County

Direct sow Microgreens outdoors after March 05 in Williamson County when soil has warmed and frost danger has passed.

With Williamson County's clay soil (46% clay), work in 3-4 inches of compost before planting Microgreens. Avoid tilling when soil is wet to prevent compaction.

Your generous 262.0-day season in Williamson County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.

General growing tips

Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.

Frequently Asked Questions

When should I plant Microgreens in Williamson County, TX?

Williamson County is in Zone 8b with an average last frost of March 5. Plan your Microgreens planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Williamson County, TX?

Williamson County, Texas is in USDA Hardiness Zone 8b. The average last spring frost is March 5 and first fall frost is November 22.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Williamson County gardeners in Zone 8b organize planting dates, track what's growing, and never miss a planting window.

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