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When to Plant Cumin in Franklin County, ID

Franklin County, Idaho Zone 6a May

What to do in May

We've pulled the most time-sensitive tasks for Franklin County, Idaho this May and put them front and centre. Tackle them in order.

Avg. last frost May 19
Avg. first frost October 3
Soil temp (4") 34°F
Watering High
Pest pressure Low
Daylight 14.4 hrs
  1. Transplant cumin outside

    Frost risk is low now in Franklin County, Idaho. If you've been covering beds overnight, you can stop.

  2. Plant cumin from seed, right in the garden

    Your soil is 34°F — warm enough for these to germinate without babying.

Coming up in June — start thinking about
  • Starting indoors: cumin

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Cumin is a warm-season annual herb whose seeds are one of the most widely used spices globally. It requires a long, hot growing season of 3-4 months.

Franklin County, Idaho is in USDA Zone 6a. The average last spring frost is May 19 and the first fall frost is October 3, giving you a growing season of approximately 137 days.

At an elevation of 7,665 feet, Franklin County receives approximately 18.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Cumin during the growing season. With low rainfall, drip irrigation is essential for growing Cumin successfully. Mulch heavily to conserve soil moisture.

Franklin County, ID (Zone 6a) Short season
137 days
Last Spring Frost May 19
137 growing days
First Fall Frost October 3
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Franklin County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 1 Transplant: Apr 29 🍅 Harvest: Aug 12 – Oct 14
Recommended (50%) ✗ May not fit
Start indoors: Apr 14 Transplant: May 12 🍅 Harvest: Aug 25 – Oct 27
Safe Start (90%) ✗ May not fit
Start indoors: May 9 Transplant: Jun 6 🍅 Harvest: Sep 19 – Nov 21

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 Franklin County

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

Soil pH

Your soil pH (6.7–7.7) is within Cumin's preferred range (6.0–8.0).

Soil Texture

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

Organic Matter

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

How to Plant Cumin

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

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

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/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 Cumin

Cumin 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 Cumin Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 2.2" 1.9" 0.3" 💧 Light watering
Jun 2.2" 1.3" 0.9" 💧 Light watering
Jul 2.2" 1.8" 0.4" 💧 Light watering
Aug 2.2" 2" 0.2" 💧 Light watering
Sep 2.2" 1.6" 0.6" 💧 Light watering
Oct 2.2" 1.8" 0.4" 💧 Light watering
Nov 1.2" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

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

Cumin 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.

Cumin needs ~1,678 GDD — county provides 2,089 GDD Good fit

Cumin Planting Timeline — Franklin County, ID

Cumin Planting Calendar

Activity When Date Range
Start Indoors April 14 Apr 14 – Apr 28
Transplant Outdoors May 12 May 12 – May 26
Direct Sow May 5 May 5 – May 26
Harvest August 25 Aug 25 – Oct 27
Fall Sowing July 25 Jul 25 – Aug 8

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–8 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

137 days in Franklin County

Growing Tips for Cumin in Franklin County

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

Common pests for Cumin in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

Franklin County receives only 18" of rain annually. Cumin needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 4 weeks before last frost. Transplant after all danger of frost. Harvest when seed heads turn brown. Requires consistent warmth for proper seed development.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cumin in Franklin County, ID?

Franklin County is in Zone 6a with an average last frost of May 19. Plan your Cumin planting based on this frost date — see the calendar above for exact timing.

What planting zone is Franklin County, ID?

Franklin County, Idaho is in USDA Hardiness Zone 6a. The average last spring frost is May 19 and first fall frost is October 3.

🌱

Your Franklin County Garden Planner — Free

A 24-page printable planner built for Franklin County (Zone 6a). 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 Franklin County, ID. 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.