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When to Plant Microgreens in Castro 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.

Castro County, Texas is in USDA Zone 7a. The average last spring frost is April 14 and the first fall frost is October 24, giving you a growing season of approximately 193 days.

At an elevation of 3,838 feet, Castro County receives approximately 47.6 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 95ยฐF, so Microgreens may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring โ€” great for early planting โ€” but Microgreens will need more frequent watering and organic matter to retain nutrients.

Castro County, TX (Zone 7a) Moderate season
193 days
Last Spring Frost April 14
193 growing days
First Fall Frost October 24

Castro County Soil Profile

Soil Type

Sandy Loam

Soil pH

7.5-8.1

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (159 days to spare)
Start indoors: Mar 3 Transplant: Apr 7 🍅 Harvest: Apr 14 – May 12
Recommended (50%) ✓ Fits season (158 days to spare)
Start indoors: Mar 10 Transplant: Apr 14 🍅 Harvest: Apr 21 – May 19
Safe Start (90%) ✓ Fits season (159 days to spare)
Start indoors: Mar 27 Transplant: May 1 🍅 Harvest: May 8 – Jun 5

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.

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 8/10 โ€” consider drought-tolerant varieties and mulching

Microgreens needs ~298 GDD — county provides 4,101 GDD Excellent fit

Microgreens Planting Timeline โ€” Castro County, TX

Microgreens Planting Calendar

Activity When Date Range
Start Indoors March 10 Mar 10 โ€“ Mar 24
Transplant Outdoors April 14 Apr 14 โ€“ Apr 28
Direct Sow March 31 Mar 31 โ€“ Apr 21
Fall Sowing August 15 Aug 15 โ€“ Aug 29
Harvest April 21 Apr 21 โ€“ May 19

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

7โ€“21 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 7a

Growing Season

193 days

Growing Tips for Castro County

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 Castro County, TX?

Castro County is in Zone 7a with an average last frost of April 14. Plan your Microgreens planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Castro County, TX?

Castro County, Texas is in USDA Hardiness Zone 7a. The average last spring frost is April 14 and first fall frost is October 24.

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Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Castro County gardeners in Zone 7a 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 Castro County, TX. Local conditions may vary. Last updated: April 2026.