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When to Plant Scallions in Colorado County, TX

Colorado County, Texas Zone 9a May

Colorado County, Texas gardeners: here's your May plan

We've pulled the most time-sensitive tasks for Colorado County, Texas this May and put them front and centre. Tackle them in order.

Avg. last frost February 26
Avg. first frost December 4
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.5 hrs
  1. Bring in the scallions

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

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Scallions (green onions) are mild-flavored alliums harvested for their slender green tops and white bases. They are quick-growing and perfect for succession planting.

Colorado County, Texas is in USDA Zone 9a. The average last spring frost is February 26 and the first fall frost is December 4, giving you a growing season of approximately 281 days.

At an elevation of 87 feet, Colorado County receives approximately 70.5 inches of rainfall annually with predominantly clay soil. Summer highs average 90°F, providing good warmth for Scallions during the growing season. Clay soil retains moisture well for Scallions, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Scallions root diseases.

Colorado County, TX (Zone 9a) Year-round
281 days
Last Spring Frost February 26
281 growing days
First Fall Frost December 4
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Colorado County Soil Profile

Soil Type

Clay

Soil pH

7.3-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (200 days to spare)
Start indoors: Jan 15 Transplant: Feb 12 🍅 Harvest: Apr 9 – May 7
Recommended (50%) ✓ Fits season (197 days to spare)
Start indoors: Jan 29 Transplant: Feb 26 🍅 Harvest: Apr 23 – May 21
Safe Start (90%) ✓ Fits season (189 days to spare)
Start indoors: Feb 20 Transplant: Mar 20 🍅 Harvest: May 15 – Jun 12

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 Colorado County

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

Soil pH

Your soil pH (7.3–7.8) is more alkaline than Scallions prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

Heavy clay soil (42% clay) in Colorado County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.

Drainage

Drainage is adequate for Scallions.

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Scallions.

How to Plant Scallions

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 Scallions

6
successive plantings in your 281-day season

Sow every 5.7 weeks. Last sowing by Sep 25 to harvest before frost.

For a dedicated fall crop, sow by Oct 09.

Plant Water Budget

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

Monthly Watering Guide for Scallions

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

Month Scallions Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 4.3" 2.3" 2" 💧 Light watering
Mar 4.3" 4.5" 0" ✅ Rainfall sufficient
Apr 4.3" 8" 0" ✅ Rainfall sufficient
May 4.3" 10.9" 0" ✅ Rainfall sufficient
Jun 4.3" 10.3" 0" ✅ Rainfall sufficient
Jul 4.3" 9.3" 0" ✅ Rainfall sufficient
Aug 4.3" 8.7" 0" ✅ Rainfall sufficient
Sep 4.3" 5.5" 0" ✅ Rainfall sufficient
Oct 4.3" 4.8" 0" ✅ Rainfall sufficient
Nov 4.3" 2.3" 2" 💧 Light watering
Dec 4.3" 1.9" 2.4" 🚿 Regular watering

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

Scallions 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.

Scallions needs ~1,050 GDD — county provides 4,935 GDD Excellent fit

Scallions Planting Timeline — Colorado County, TX

Scallions Planting Calendar

Activity When Date Range
Start Indoors January 29 Jan 29 – Feb 12
Transplant Outdoors February 26 Feb 26 – Mar 12
Direct Sow February 5 Feb 5 – Feb 26
Harvest April 23 Apr 23 – May 21
Fall Sowing October 9 Oct 9 – Oct 23

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

281 days in Colorado County

Growing Tips for Scallions in Colorado County

Direct sow Scallions outdoors after February 26 in Colorado County when soil has warmed and frost danger has passed.

With Colorado County's clay soil (42% clay), work in 3-4 inches of compost before planting Scallions. Avoid tilling when soil is wet to prevent compaction.

Common pests for Scallions in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow every 3 weeks for continuous harvest. Thin to 1 inch apart or grow in clusters. Harvest when pencil-thick by pulling or cutting at soil level.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Scallions in Colorado County, TX?

Colorado County is in Zone 9a with an average last frost of February 26. Plan your Scallions planting based on this frost date — see the calendar above for exact timing.

What planting zone is Colorado County, TX?

Colorado County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is February 26 and first fall frost is December 4.

🌱

Your Colorado County Garden Planner — Free

A 24-page printable planner built for Colorado County (Zone 9a). 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 Colorado 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.