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When to Plant Alliums in Grant County, NE

Grant County, Nebraska Zone 5a June

This month in Grant County, Nebraska

Your garden in Grant County, Nebraska is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost May 13
Avg. first frost October 5
Soil temp (4") 64°F
Watering High
Pest pressure High
Daylight 15 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.

Grant County, Nebraska is in USDA Zone 5a. The average last spring frost is May 13 and the first fall frost is October 5, giving you a growing season of approximately 145 days.

At an elevation of 689 feet, Grant County receives approximately 24.2 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Alliums to ensure they mature before fall.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Grant County, NE (Zone 5a) Short season
145 days
Last Spring Frost May 13
145 growing days
First Fall Frost October 5

Grant County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.5

Drainage

Well Drained

Alliums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (80 days to spare)
Transplant: May 8 🌸 Bloom: Jun 12 – Jul 10
Recommended (50%) ✓ Fits season (82 days to spare)
Transplant: May 13 🌸 Bloom: Jun 17 – Jul 15
Safe Start (90%) ✓ Fits season (83 days to spare)
Transplant: May 21 🌸 Bloom: Jun 25 – Jul 23

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 Grant County

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

Soil pH

Your soil pH (6.2–7.5) is within Alliums's preferred range (5.5–7.5).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.7%). Annual compost additions will help Alliums.

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

6
successive plantings in your 145-day season

Sow every 3.1 weeks. Last sowing by Aug 24 to harvest before frost.

For a dedicated fall crop, sow by Aug 24.

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 8/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 2.2" 2.8" 0" ✅ Rainfall sufficient
Jun 2.2" 1.6" 0.6" 💧 Light watering
Jul 2.2" 1.9" 0.3" 💧 Light watering
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2.1" 0.1" 💧 Light watering
Oct 2.2" 2.5" 0" ✅ Rainfall sufficient
Nov 1.7" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Grant 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 ~350 GDD — county provides 1,450 GDD Excellent fit

Alliums Planting Timeline — Grant County, NE

Alliums Planting Calendar

Activity When Date Range
Bloom September 28 Sep 28 – Oct 26
Fall Sowing August 24 Aug 24 – Sep 7

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

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 5a

📆 Growing Season

145 days in Grant County

Growing Tips for Alliums in Grant County

Direct sow Alliums outdoors after May 13 in Grant County when soil has warmed and frost danger has passed.

Your generous 145.0-day season in Grant 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.

Grant County receives only 24" of rain annually. Alliums needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Grant County, NE?

Grant County is in Zone 5a with an average last frost of May 13. Plan your Alliums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Grant County, NE?

Grant County, Nebraska is in USDA Hardiness Zone 5a. The average last spring frost is May 13 and first fall frost is October 5.

🌱

Your Grant County Garden Planner — Free

A 22-page printable planner built for Grant County (Zone 5a). 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 Grant County, NE. Local conditions may vary. Last updated: June 2026.

Sources & credits

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