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When to Plant Basil in Kootenai County, ID

Kootenai County, Idaho Zone 6b May

May in the garden — Kootenai County, Idaho

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

Avg. last frost April 29
Avg. first frost October 8
Soil temp (4") 46°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Set out basil seedlings

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Outdoor sowing time: basil

    Your soil is 46°F — warm enough for these to germinate without babying.

A few tasks this May that'll pay off in June
  • Starting indoors: basil

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Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Kootenai County, Idaho is in USDA Zone 6b. The average last spring frost is April 29 and the first fall frost is October 8, giving you a growing season of approximately 162 days.

At an elevation of 5,986 feet, Kootenai County receives approximately 20.7 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Basil during the growing season.

Kootenai County, ID (Zone 6b) Moderate season
162 days
Last Spring Frost April 29
162 growing days
First Fall Frost October 8
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Kootenai County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Jul 1 – Sep 2
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Mar 11 Transplant: May 13 🍅 Harvest: Jul 8 – Sep 9
Safe Start (90%) ✓ Fits season (32 days to spare)
Start indoors: Mar 29 Transplant: May 31 🍅 Harvest: Jul 26 – Sep 27

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 Kootenai County

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

Soil pH

Your soil pH (6.7–7.7) is more alkaline than Basil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Basil.

How to Plant Basil

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

Succession Planting Basil

3
successive plantings in your 162-day season

Sow every 5.7 weeks. Last sowing by Jul 25 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 110 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.6" 2.4" 0.2" 💧 Light watering
May 2.6" 2.7" 0" ✅ Rainfall sufficient
Jun 2.6" 1.3" 1.3" 🚿 Regular watering
Jul 2.6" 1.9" 0.7" 💧 Light watering
Aug 2.6" 2" 0.6" 💧 Light watering
Sep 2.6" 1.9" 0.7" 💧 Light watering
Oct 2.6" 1.5" 1.1" 💧 Light watering
Nov 1.3" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

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

Basil 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.

Basil needs ~906 GDD — county provides 2,349 GDD Excellent fit

Basil Planting Timeline — Kootenai County, ID

Basil Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors May 13 May 13 – May 27
Direct Sow May 6 May 6 – May 27
Harvest July 8 Jul 8 – Sep 9

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · Only during dry spells

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

162 days in Kootenai County

Growing Tips for Basil in Kootenai County

Direct sow Basil outdoors after April 29 in Kootenai County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Kootenai County, ID?

Kootenai County is in Zone 6b with an average last frost of April 29. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kootenai County, ID?

Kootenai County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is April 29 and first fall frost is October 8.

🌱

Your Kootenai County Garden Planner — Free

A 24-page printable planner built for Kootenai County (Zone 6b). 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 Kootenai 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.