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When to Plant Onion in Piscataquis County, ME

Piscataquis County, Maine Zone 5a May

Your May gardening checklist

May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Piscataquis County, Maine.

Avg. last frost May 19
Avg. first frost September 28
Soil temp (4") 52°F
Watering Low
Pest pressure Low
Daylight 14.7 hrs
  1. Move onion from tray to bed

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Put onion seeds straight in the ground

    Mark the row. Birds and stray feet both have opinions about unmarked beds.

Looking ahead to June
  • Starting indoors: onion

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Onions are a fundamental kitchen staple available in yellow, white, and red varieties. Choose long-day, short-day, or intermediate types based on your latitude.

Piscataquis County, Maine is in USDA Zone 5a. The average last spring frost is May 19 and the first fall frost is September 28, giving you a growing season of approximately 132 days.

At an elevation of 727 feet, Piscataquis County receives approximately 49.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Onion to ensure they mature before fall.

Piscataquis County, ME (Zone 5a) Short season
132 days
Last Spring Frost May 19
132 growing days
First Fall Frost September 28

Piscataquis County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 10 Transplant: May 15 🍅 Harvest: Aug 14 – Oct 2
Recommended (50%) ✗ May not fit
Start indoors: Apr 14 Transplant: May 19 🍅 Harvest: Aug 18 – Oct 6
Safe Start (90%) ✗ May not fit
Start indoors: Apr 27 Transplant: Jun 1 🍅 Harvest: Aug 31 – Oct 19

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 Piscataquis County

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

Soil pH

Your soil pH (5.0–6.5) is more acidic than Onion prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.3%). Annual compost additions will help Onion.

How to Plant Onion

1"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

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

Monthly Watering Guide for Onion

Onion needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Onion Needs Rainfall You Supplement Action
Jan 3.5" 0" ❄️ Dormant
Feb 3.6" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.4" 0" ❄️ Dormant
May 4.3" 4.8" 0" ✅ Rainfall sufficient
Jun 4.3" 5.1" 0" ✅ Rainfall sufficient
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 4.6" 0" ✅ Rainfall sufficient
Oct 3.8" 0" ❄️ Dormant
Nov 3.2" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

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

Onion 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.

Onion needs ~892 GDD — county provides 1,122 GDD Good fit

Onion Planting Timeline — Piscataquis County, ME

Onion Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 – Apr 28
Transplant Outdoors May 19 May 19 – Jun 2
Direct Sow May 5 May 5 – May 26
Harvest August 18 Aug 18 – Oct 6
Fall Sowing July 20 Jul 20 – Aug 3

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors
July Fall Sowing
August Fall Sowing Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

132 days in Piscataquis County

Growing Tips for Onion in Piscataquis County

Direct sow Onion outdoors after May 19 in Piscataquis County when soil has warmed and frost danger has passed.

Your 132.0-day growing season in Piscataquis County is tight for Onion (90.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Start seeds indoors 8-10 weeks before transplanting. Match day-length type to your latitude. Stop watering when tops begin to fall over and cure bulbs for 2-3 weeks before storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans
  • Asparagus

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Onion in Piscataquis County, ME?

Piscataquis County is in Zone 5a with an average last frost of May 19. Plan your Onion planting based on this frost date — see the calendar above for exact timing.

What planting zone is Piscataquis County, ME?

Piscataquis County, Maine is in USDA Hardiness Zone 5a. The average last spring frost is May 19 and first fall frost is September 28.

🌱

Your Piscataquis County Garden Planner — Free

A 24-page printable planner built for Piscataquis 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 Piscataquis County, ME. Local conditions may vary. Last updated: May 2026.

Sources & credits

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