Blog

When to plant Alliums in Kennebec County County,

Kennebec County County's climate puts the Alliums spring window between mid-spring and late spring. time plantings around the expected last-frost window for best survival. A second sowing from August 24 to September 7 extends the harvest into fall.

When to Plant Alliums in Kennebec County, ME

Kennebec County, Maine Zone 5b June

What to do in June

June is a pivotal month for Kennebec County, Maine gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 10
Avg. first frost October 5
Soil temp (4") 68°F
Watering Moderate
Pest pressure High
Daylight 15.3 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.

Kennebec County, Maine is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 5, giving you a growing season of approximately 148 days.

At an elevation of 1,032 feet, Kennebec County receives approximately 42.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°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
Kennebec County, ME (Zone 5b) Short season
148 days
Last Spring Frost May 10
148 growing days
First Fall Frost October 5

Kennebec County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.4

Drainage

Well Drained

Alliums Planting Risk Windows

Early Start (70% safe) ✓ Fits season (89 days to spare)
Transplant: May 4 🌸 Bloom: Jun 8 – Jun 29
Recommended (50%) ✓ Fits season (92 days to spare)
Transplant: May 10 🌸 Bloom: Jun 14 – Jul 5
Safe Start (90%) ✓ Fits season (89 days to spare)
Transplant: May 27 🌸 Bloom: Jul 1 – Jul 22

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 Kennebec County

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

Soil pH

Your soil pH (5.1–6.4) overlaps with Alliums's range (5.5–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). 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 148-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
1.2″/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 3.3" 0" ❄️ Dormant
Feb 2.8" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 3.4" 0" ❄️ Dormant
May 2.2" 3.7" 0" ✅ Rainfall sufficient
Jun 2.2" 3.7" 0" ✅ Rainfall sufficient
Jul 2.2" 3.9" 0" ✅ Rainfall sufficient
Aug 2.2" 4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
Oct 2.2" 3.8" 0" ✅ Rainfall sufficient
Nov 3.1" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Kennebec 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 ~455 GDD — county provides 1,924 GDD Excellent fit

Alliums Planting Timeline — Kennebec County, ME

Alliums Planting Calendar

Activity When Date Range
Bloom September 28 Sep 28 – Oct 19
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: acceptable

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Kennebec County

Growing Tips for Alliums in Kennebec County

Direct sow Alliums outdoors after May 10 in Kennebec County when soil has warmed and frost danger has passed.

Your generous 148.0-day season in Kennebec 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 Kennebec County, ME?

Kennebec County is in Zone 5b with an average last frost of May 10. Plan your Alliums planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kennebec County, ME?

Kennebec County, Maine is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is October 5.

When should I plant Alliums in Kennebec County County, ?

In Kennebec County County, , plant Alliums after the last frost (around May 10) and before the first frost (around October 5). Best results when soil holds above 50°F.

What growing zone is Kennebec County County, for Alliums?

Kennebec County 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 Kennebec County County's climate?

Yes — Alliums grows well in Kennebec County County's temperate climate. Kennebec County County averages a 148-day frost-free season, with last frost around May 10 and first frost around October 5.

🌱

Your Kennebec County Garden Planner — Free

A 22-page printable planner built for Kennebec 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.

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 Kennebec County, ME. 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.