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When to plant Alliums in Elbert County County,

Elbert County County's spring Alliums window runs mid-spring through late spring. time plantings around the expected last-frost window for best survival. A second sowing from August 22 to September 5 extends the harvest into fall.

When to Plant Alliums in Elbert County, CO

Elbert County, Colorado Zone 5b June

What to do in June

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

Avg. last frost May 12
Avg. first frost October 3
Soil temp (4") 54°F
Watering High
Pest pressure High
Daylight 14.7 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.

Elbert County, Colorado is in USDA Zone 5b. The average last spring frost is May 12 and the first fall frost is October 3, giving you a growing season of approximately 144 days.

At an elevation of 5,587 feet, Elbert County receives approximately 22.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Alliums during the growing season.

Bulb Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting
Elbert County, CO (Zone 5b) Short season
144 days
Last Spring Frost May 12
144 growing days
First Fall Frost October 3
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Elbert County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.7

Drainage

Well Drained

Alliums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (87 days to spare)
Transplant: May 3 🌸 Bloom: Jun 7 – Jun 28
Recommended (50%) ✓ Fits season (88 days to spare)
Transplant: May 12 🌸 Bloom: Jun 16 – Jul 7
Safe Start (90%) ✓ Fits season (85 days to spare)
Transplant: May 28 🌸 Bloom: Jul 2 – 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 Elbert County

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

Soil pH

Your soil pH (6.2–7.7) overlaps with Alliums's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Alliums.

Organic Matter

Organic matter is moderate (2.8%). 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 144-day season

Sow every 3.1 weeks. Last sowing by Aug 22 to harvest before frost.

For a dedicated fall crop, sow by Aug 22.

Alliums Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.0″/week
Watering frequency Only during dry spells
Season total 8 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 1.4" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.2" 0" ❄️ Dormant
May 2.2" 2.4" 0" ✅ Rainfall sufficient
Jun 2.2" 1.7" 0.5" 💧 Light watering
Jul 2.2" 1.9" 0.3" 💧 Light watering
Aug 2.2" 2.3" 0" ✅ Rainfall sufficient
Sep 2.2" 2" 0.2" 💧 Light watering
Oct 2.2" 1.9" 0.3" 💧 Light watering
Nov 1.8" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Elbert 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 ~534 GDD — county provides 2,196 GDD Excellent fit

Alliums Planting Timeline — Elbert County, CO

Alliums Planting Calendar

Activity When Date Range
Bloom September 26 Sep 26 – Oct 17
Fall Sowing August 22 Aug 22 – Sep 5

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
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

28–42 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

144 days in Elbert County

Growing Tips for Alliums in Elbert County

Direct sow Alliums outdoors after May 12 in Elbert County when soil has warmed and frost danger has passed.

Your generous 144.0-day season in Elbert 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.

Elbert County receives only 22" 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 Elbert County, CO?

Elbert County is in Zone 5b with an average last frost of May 12. Plan your Alliums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Elbert County, CO?

Elbert County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 12 and first fall frost is October 3.

When should I plant Alliums in Elbert County, ?

In Elbert County, , plant Alliums after the last frost (around May 12) and before the first frost (around October 3). Best results when soil holds above 50°F.

What growing zone is Elbert County, for Alliums?

Elbert County sits in USDA Zone 5b. Alliums grows reliably in zones 3a through 9b, so it's a good fit here.

Can Alliums grow in Elbert County's climate?

Yes — Alliums grows well in Elbert County's temperate climate. Elbert County averages a 144-day frost-free season, with last frost around May 12 and first frost around October 3.

🌱

Your Elbert County Garden Planner — Free

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

Sources & credits

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