Blog

When to plant Basil in Viola, ID

In Viola, Basil is a single-season spring crop — there's no second fall window. Plant May 18–June 8 for an 50–75-day harvest, finishing well before the September 23 first frost.

When to Plant Basil in Viola, ID

Basil
Latah County, Idaho Zone 6b June

Your June gardening checklist

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

Avg. last frost May 11
Avg. first frost September 23
Soil temp (4") 53°F
Watering Critical
Pest pressure High
Daylight 15.6 hrs
  1. Start basil indoors

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

Before July arrives, get these ready
  • First harvests: basil

Instant PDF download. No spam, unsubscribe any time.

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.

Viola, Idaho is in USDA Zone 6b. The average last spring frost is May 11 and the first fall frost is September 23, giving you a growing season of approximately 135 days.

At an elevation of 5,530 feet, Latah County receives approximately 14.8 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Basil during the growing season. With low rainfall, drip irrigation is essential for growing Basil successfully. Mulch heavily to conserve soil moisture.

Viola, ID (Zone 6b) Short season
135 days
Last Spring Frost May 11
135 growing days
First Fall Frost September 23

Viola Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (2 days to spare)
Start indoors: Mar 16 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 14
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Mar 23 Transplant: May 25 🍅 Harvest: Jul 20 – Sep 21
Safe Start (90%) ✗ May not fit
Start indoors: Apr 17 Transplant: Jun 19 🍅 Harvest: Aug 14 – Oct 16

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 Viola

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

Soil pH

Your soil pH (6.7–8.0) is more alkaline than Basil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Basil.

Organic Matter

Organic matter is moderate (2.6%). 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 135-day season

Sow every 5.7 weeks. Last sowing by Jul 10 to harvest before frost.

Basil Water Budget

Plant needs
0.6″/week
Rainfall provides
0.5″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 461 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.3" 0" ❄️ Dormant
Apr 1.3" 0" ❄️ Dormant
May 2.6" 1.6" 1" 💧 Light watering
Jun 2.6" 1" 1.6" 🚿 Regular watering
Jul 2.6" 1.4" 1.2" 💧 Light watering
Aug 2.6" 1.7" 0.9" 💧 Light watering
Sep 2.6" 1.3" 1.3" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 1" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Latah 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 1,957 GDD Excellent fit

Basil Planting Timeline — Viola, ID

Basil Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors May 25 May 25 – Jun 8
Direct Sow May 18 May 18 – Jun 8
Harvest July 20 Jul 20 – Sep 21

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.6"/week · 1-2 times/week

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

135 days in Latah County

Growing Tips for Basil in Viola

Direct sow Basil outdoors after May 11 in Latah 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.

When should I plant Basil in Viola, ID?

In Viola, ID, plant Basil after the last frost (around May 11) and before the first frost (around September 23). Best results when soil holds above 50°F.

What growing zone is Viola, ID for Basil?

Viola sits in USDA Zone 6b. Basil grows reliably in zones 4a through 11b, so it's a good fit here.

Can Basil grow in Viola's climate?

Yes — Basil grows well in Viola's temperate climate. Viola averages a 135-day frost-free season, with last frost around May 11 and first frost around September 23.

🌱

Your Latah County Garden Planner — Free

A 22-page printable planner built for Latah 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.

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 Latah County, ID. Local conditions may vary. Last updated: June 2026.