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When to plant Snapdragon in Lewis County County,

Lewis County County's 126-day season only supports one Snapdragon planting per year. Sow between April 29 and May 20 for the best chance at full maturity before September 23.

When to Plant Snapdragon in Lewis County, ID

Lewis County, Idaho Zone 6b June

June to-do list for Lewis County, Idaho

Your Lewis County, Idaho garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost May 20
Avg. first frost September 23
Soil temp (4") 57°F
Watering Critical
Pest pressure High
Daylight 15.6 hrs
Looking ahead to July
  • Starting indoors: snapdragon
  • First harvests: snapdragon

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Snapdragons (Antirrhinum majus) are classic cool-season annuals whose upright spikes of dragon-lipped flowers are among spring's most dramatic displays. Tolerating light frosts, they bloom from early spring until summer heat shuts them down — then often revive in fall. In zones 9-11 they are grown as fall-planted winter annuals and may re-seed to naturalize.

Lewis County, Idaho is in USDA Zone 6b. The average last spring frost is May 20 and the first fall frost is September 23, giving you a growing season of approximately 126 days.

At an elevation of 4,861 feet, Lewis County receives approximately 13.5 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Snapdragon during the growing season. With low rainfall, drip irrigation is essential for growing Snapdragon successfully. Mulch heavily to conserve soil moisture.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Lewis County, ID (Zone 6b) Short season
126 days
Last Spring Frost May 20
126 growing days
First Fall Frost September 23

Lewis County Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Snapdragon Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 3 Transplant: May 12 🌸 Bloom: Jul 21 – Oct 6
Recommended (50%) ✗ May not fit
Start indoors: Mar 11 Transplant: May 20 🌸 Bloom: Jul 29 – Oct 14
Safe Start (90%) ✗ May not fit
Start indoors: Apr 1 Transplant: Jun 10 🌸 Bloom: Aug 19 – Nov 4

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 Lewis County

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

Soil pH

Your soil pH (6.7–8.0) is more alkaline than Snapdragon prefers (6.2–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Snapdragon.

How to Plant Snapdragon

9"
Between Plants
12"
Between Rows

Succession Planting Snapdragon

2
successive plantings in your 126-day season

Sow every 8 weeks. Last sowing by Jun 15 to harvest before frost.

Snapdragon Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 740 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Snapdragon

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

Month Snapdragon Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 4.3" 1.7" 2.6" 🚿 Regular watering
Jun 4.3" 0.8" 3.5" 🚿 Regular watering
Jul 4.3" 1.2" 3.1" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1.2" 3.1" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Snapdragon 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.

Snapdragon needs ~1,488 GDD — county provides 2,205 GDD Excellent fit

Snapdragon Planting Timeline — Lewis County, ID

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors March 11 Mar 11 – Mar 25
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow April 29 Apr 29 – May 20
Bloom July 29 Jul 29 – Oct 14

· 9" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6.2–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

126 days in Lewis County

Growing Tips for Snapdragon in Lewis County

Direct sow Snapdragon outdoors after May 20 in Lewis County when soil has warmed and frost danger has passed.

Lewis County receives only 14" of rain annually. Snapdragon needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start indoors 10-12 weeks before last frost; seeds need light to germinate — press into moist medium and do not cover. Transplant after hardening off, even if light frosts remain. Pinch seedlings once to encourage branching. Deadhead to prolong blooming. In zones 8-11, sow in fall for a winter-to-spring show. Tall varieties (24-36") make excellent cut flowers.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Snapdragon in Lewis County, ID?

Lewis County is in Zone 6b with an average last frost of May 20. Plan your Snapdragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lewis County, ID?

Lewis County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 20 and first fall frost is September 23.

When should I plant Snapdragon in Lewis County County, ?

In Lewis County County, , plant Snapdragon after the last frost (around May 20) and before the first frost (around September 23). Best results when soil holds above 50°F.

What growing zone is Lewis County County, for Snapdragon?

Lewis County County sits in USDA Zone 6b. Snapdragon grows reliably in zones 2a through 11b, so it's a good fit here.

Can Snapdragon grow in Lewis County County's climate?

Yes — Snapdragon grows well in Lewis County County's temperate climate. Lewis County County averages a 126-day frost-free season, with last frost around May 20 and first frost around September 23.

🌱

Your Lewis County Garden Planner — Free

A 22-page printable planner built for Lewis 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 Lewis County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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