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When to Plant Alliums in Zapata County, TX

Zapata County, Texas Zone 9b July

This month in Zapata County, Texas

A quick July briefing for Zapata County, Texas gardeners — what's urgent, what's next, and what can wait.

Avg. last frost February 3
Avg. first frost December 14
Soil temp (4") 89°F
Watering Low
Pest pressure High
Daylight 13.5 hrs

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Ornamental alliums (Allium spp.) bridge the gap between spring and summer with their striking globe-shaped flower heads in shades of purple, violet, white, and pink. Blooming after tulips have faded, they extend the spring display well into early summer. 'Gladiator', 'Globemaster', and 'Purple Sensation' produce softball-sized heads on 18–36 inch stems, while smaller species create charming accents at border fronts. Deer and rodents shun them completely due to the characteristic onion scent. Dried seed heads provide architectural interest into fall.

Zapata County, Texas is in USDA Zone 9b. The average last spring frost is February 3 and the first fall frost is December 14, giving you a growing season of approximately 314 days.

At an elevation of 3,340 feet, Zapata County receives approximately 60.6 inches of rainfall annually with predominantly loam soil. Summer highs average 103°F, so Alliums may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Alliums root diseases.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Zapata County, TX (Zone 9b) Year-round
314 days
Last Spring Frost February 3
314 growing days
First Fall Frost December 14

Zapata County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Alliums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (274 days to spare)
Transplant: Jan 17 🌸 Bloom: Feb 14 – Mar 7
Recommended (50%) ✓ Fits season (265 days to spare)
Transplant: Feb 3 🌸 Bloom: Mar 3 – Mar 24
Safe Start (90%) ✓ Fits season (251 days to spare)
Transplant: Feb 27 🌸 Bloom: Mar 27 – Apr 17

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 Zapata County

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

Soil pH

Your soil pH (6.2–7.6) overlaps with Alliums's range (5.5–7.5), though not a perfect match.

Soil Texture

The loam soil in Zapata County is excellent for Alliums — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Alliums.

How to Plant Alliums

5"
Planting Depth
7"
Between Plants
8"
Between Rows

Fall planting: Sow 3 weeks before your first frost date for a fall harvest.

Succession Planting Alliums

14
successive plantings in your 314-day season

Sow every 3.1 weeks. Last sowing by Nov 02 to harvest before frost.

For a dedicated fall crop, sow by Nov 23.

Alliums Water Budget

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

Monthly Watering Guide for Alliums

Alliums needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Alliums Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 2.2" 2.3" 0" ✅ Rainfall sufficient
Mar 2.2" 4.1" 0" ✅ Rainfall sufficient
Apr 2.2" 6.3" 0" ✅ Rainfall sufficient
May 2.2" 7.6" 0" ✅ Rainfall sufficient
Jun 2.2" 10.1" 0" ✅ Rainfall sufficient
Jul 2.2" 8.6" 0" ✅ Rainfall sufficient
Aug 2.2" 7.4" 0" ✅ Rainfall sufficient
Sep 2.2" 6.1" 0" ✅ Rainfall sufficient
Oct 2.2" 3.3" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 2.2" 1.3" 0.9" 💧 Light watering

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

Alliums 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.

Alliums needs ~954 GDD — county provides 8,583 GDD Excellent fit

Alliums Planting Timeline — Zapata County, TX

Alliums Planting Calendar

Activity When Date Range
Bloom December 21 Dec 21 – Jan 11
Fall Sowing November 23 Nov 23 – Dec 7

Plant 5" deep · 7" apart · Rows 8" apart

Month-by-Month Timeline

MonthActivities
January Bloom
February
March
April
May
June
July
August
September
October
November Fall Sowing
December Fall Sowing Bloom

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

28–42 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

314 days in Zapata County

Growing Tips for Alliums in Zapata County

Direct sow Alliums outdoors after February 03 in Zapata County when soil has warmed and frost danger has passed.

With summer highs reaching 103°F in Zapata County, provide afternoon shade for Alliums and water deeply in the morning.

Your generous 315.0-day season in Zapata County allows multiple plantings of Alliums. Sow every 14.0 days for continuous harvest.

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

General growing tips

Plant bulbs in fall, 3–4 times as deep as the bulb diameter (typically 4–6 inches for large types, 3 inches for small species). Space 6–8 inches apart for standard cultivars. Foliage often looks untidy as it dies back before bloom — plant around perennials that will conceal the yellowing leaves. Excellent drainage is essential; alliums rot in wet soils. Leave bulbs in place for naturalization; divide every 3–4 years when clusters become congested. Deadhead spent globes or leave for ornamental seedheads and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Beans
  • Peas

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Alliums in Zapata County, TX?

Zapata County is in Zone 9b with an average last frost of February 3. Plan your Alliums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Zapata County, TX?

Zapata County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 3 and first fall frost is December 14.

🌱

Your Zapata County Garden Planner — Free

A 22-page printable planner built for Zapata 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 Zapata County, TX. Local conditions may vary. Last updated: July 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.