Blog

When to plant Alliums in Thomas County County,

In Zone 6a (Thomas County County), direct-sow Alliums between mid-spring and late spring for spring, after the April 30 last-frost mark. A second sowing from August 31 to September 14 extends the harvest into fall.

When to Plant Alliums in Thomas County, KS

Thomas County, Kansas Zone 6a June

Top priorities for Thomas County, Kansas gardeners in June

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Thomas County, Kansas.

Avg. last frost April 30
Avg. first frost October 12
Soil temp (4") 71°F
Watering High
Pest pressure High
Daylight 14.8 hrs

Instant PDF download. No spam, unsubscribe any time.

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.

Thomas County, Kansas is in USDA Zone 6a. The average last spring frost is April 30 and the first fall frost is October 12, giving you a growing season of approximately 165 days.

At an elevation of 810 feet, Thomas County receives approximately 26.4 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Alliums during the growing season.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Thomas County, KS (Zone 6a) Moderate season
165 days
Last Spring Frost April 30
165 growing days
First Fall Frost October 12
Share this guide:

Thomas County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.5

Drainage

Well Drained

Alliums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (108 days to spare)
Transplant: Apr 25 🌸 Bloom: May 23 – Jun 20
Recommended (50%) ✓ Fits season (109 days to spare)
Transplant: Apr 30 🌸 Bloom: May 28 – Jun 25
Safe Start (90%) ✓ Fits season (106 days to spare)
Transplant: May 14 🌸 Bloom: Jun 11 – Jul 9

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 Thomas County

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

Soil pH

Your soil pH (6.8–7.5) is within Alliums's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.1%) — Alliums will thrive.

How to Plant Alliums

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

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Succession Planting Alliums

7
successive plantings in your 165-day season

Sow every 3.1 weeks. Last sowing by Aug 31 to harvest before frost.

For a dedicated fall crop, sow by Aug 31.

Alliums Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/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 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 2.1" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2.2" 0" ❄️ Dormant
Apr 2.2" 3.1" 0" ✅ Rainfall sufficient
May 2.2" 3.2" 0" ✅ Rainfall sufficient
Jun 2.2" 2" 0.2" 💧 Light watering
Jul 2.2" 2.3" 0" ✅ Rainfall sufficient
Aug 2.2" 2.6" 0" ✅ Rainfall sufficient
Sep 2.2" 2.1" 0.1" 💧 Light watering
Oct 2.2" 2.3" 0" ✅ Rainfall sufficient
Nov 1.7" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Thomas 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 ~560 GDD — county provides 2,640 GDD Excellent fit

Alliums Planting Timeline — Thomas County, KS

Alliums Planting Calendar

Activity When Date Range
Bloom September 28 Sep 28 – Oct 26
Fall Sowing August 31 Aug 31 – Sep 14

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

Month-by-Month Timeline

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

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: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

165 days in Thomas County

Growing Tips for Alliums in Thomas County

Direct sow Alliums outdoors after April 30 in Thomas County when soil has warmed and frost danger has passed.

Your generous 165.0-day season in Thomas 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 Thomas County, KS?

Thomas County is in Zone 6a with an average last frost of April 30. Plan your Alliums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Thomas County, KS?

Thomas County, Kansas is in USDA Hardiness Zone 6a. The average last spring frost is April 30 and first fall frost is October 12.

When should I plant Alliums in Thomas County County, ?

In Thomas County County, , plant Alliums after the last frost (around April 30) and before the first frost (around October 12). Best results when soil holds above 50°F.

What growing zone is Thomas County County, for Alliums?

Thomas County County sits in USDA Zone 6a. Alliums grows reliably in zones 3a through 9b, so it's a good fit here.

Can Alliums grow in Thomas County County's climate?

Yes — Alliums grows well in Thomas County County's temperate climate. Thomas County County averages a 165-day frost-free season, with last frost around April 30 and first frost around October 12.

🌱

Your Thomas County Garden Planner — Free

A 22-page printable planner built for Thomas County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Thomas County, KS. Local conditions may vary. Last updated: June 2026.

Sources & credits

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