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When to Plant Mint in Oneida County, ID

Mint is a vigorous perennial herb with refreshing, aromatic leaves used in teas, cocktails, and cooking. It spreads aggressively by underground runners.

Oneida County, Idaho is in USDA Zone 5a. The average last spring frost is May 23 and the first fall frost is September 20, giving you a growing season of approximately 120 days.

At an elevation of 8,042 feet, Oneida County receives approximately 18.4 inches of rainfall annually with predominantly loam soil. Summer highs average 85ยฐF, providing good warmth for Mint during the growing season. With low rainfall, drip irrigation is essential for growing Mint successfully. Mulch heavily to conserve soil moisture.

Oneida County, ID (Zone 5a) Short season
120 days
Last Spring Frost May 23
120 growing days
First Fall Frost September 20

Oneida County Soil Profile

Soil Type

Loam

Soil pH

6.3-8.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 19 🍅 Harvest: Jul 21 – Sep 29
Recommended (50%) ✗ May not fit
Transplant: May 30 🍅 Harvest: Aug 1 – Oct 10
Safe Start (90%) ✗ May not fit
Transplant: Jun 22 🍅 Harvest: Aug 24 – Nov 2

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 Oneida County

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

Soil pH

Your soil pH (6.3โ€“8.2) is more alkaline than Mint prefers (6.0โ€“7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Oneida County is excellent for Mint โ€” good drainage, moisture retention, and nutrient holding capacity.

Drainage

Mint is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Mint.

How to Plant Mint

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Mint

2
successive plantings in your 120-day season

Sow every 6.9 weeks. Last sowing by Jun 22 to harvest before frost.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.6″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 341 gal / 100 sq ft
Drought risk

Water stress score is 8/10 โ€” consider drought-tolerant varieties and mulching

Monthly Watering Guide for Mint

Mint needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Mint Needs Rainfall You Supplement Action
Jan โ€” 1.2" 0" โ„๏ธ Dormant
Feb โ€” 1" 0" โ„๏ธ Dormant
Mar โ€” 1.8" 0" โ„๏ธ Dormant
Apr โ€” 1.8" 0" โ„๏ธ Dormant
May 3" 2.1" 0.9" ๐Ÿ’ง Light watering
Jun 3" 1.1" 1.9" ๐Ÿšฟ Regular watering
Jul 3" 1.8" 1.2" ๐Ÿ’ง Light watering
Aug 3" 2" 1" ๐Ÿ’ง Light watering
Sep 3" 1.7" 1.3" ๐Ÿ’ง Light watering
Oct โ€” 1.7" 0" โ„๏ธ Dormant
Nov โ€” 1.3" 0" โ„๏ธ Dormant
Dec โ€” 0.9" 0" โ„๏ธ Dormant

Water needs are for active growing months only (Mayโ€“Sep in Oneida County). Supplement amounts are based on average rainfall โ€” actual needs vary with temperature, soil, and mulching.

Mint 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" โ€” every day above 50ยฐF 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.

Mint needs ~1,031 GDD — county provides 1,650 GDD Excellent fit

Mint Planting Timeline โ€” Oneida County, ID

Mint Planting Calendar

Activity When Date Range
Transplant Outdoors May 30 May 30 โ€“ Jun 13
Harvest August 1 Aug 1 โ€“ Oct 10

Plant 0.5" deep ยท 8" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March โ€”
April โ€”
May Transplant Outdoors
June Transplant Outdoors
July โ€”
August Harvest
September Harvest
October Harvest
November โ€”
December โ€”

Growing Conditions

โ˜€๏ธ Sun

Partial Shade (3-6 hours)

๐Ÿ’ง Water

0.7"/week ยท 1-2 times/week

๐Ÿ“… Days to Maturity

60โ€“90 days

๐Ÿงช Soil pH

Needs 6โ€“7 ยท Your soil: too_alkaline

๐Ÿ—บ๏ธ USDA Zone

Zone 5a

๐Ÿ“† Growing Season

120 days in Oneida County

Growing Tips for Mint in Oneida County

Direct sow Mint outdoors after May 23 in Oneida County when soil has warmed and frost danger has passed.

General growing tips

Always grow mint in containers or with underground barriers to control spreading. Harvest regularly to keep plants compact. Cut plants back in late summer for a fresh fall flush.

Companion Planting

Good Companions

Avoid Planting Near

  • Parsley

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mint in Oneida County, ID?

Oneida County is in Zone 5a with an average last frost of May 23. Plan your Mint planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Oneida County, ID?

Oneida County, Idaho is in USDA Hardiness Zone 5a. The average last spring frost is May 23 and first fall frost is September 20.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Oneida County gardeners in Zone 5a organize planting dates, track what's growing, and never miss a planting window.

Get Your Free Garden Planner →

Free download. Plan your entire garden season in minutes.

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