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When to Plant Snapdragon in Benton County, WA

Benton County, Washington Zone 7b June

June in Benton County, Washington — your action list

We've pulled the most time-sensitive tasks for Benton County, Washington this June and put them front and centre. Tackle them in order.

Avg. last frost April 3
Avg. first frost October 27
Soil temp (4") 71°F
Watering Critical
Pest pressure High
Daylight 15.6 hrs
  1. Start snapdragon under lights

    You're about 19 weeks out from your last frost — the perfect window to get these germinating indoors.

  2. It's harvest week for snapdragon

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

To set up a strong July, finish these tasks
  • 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.

Benton County, Washington is in USDA Zone 7b. The average last spring frost is April 3 and the first fall frost is October 27, giving you a growing season of approximately 207 days.

At an elevation of 2,633 feet, Benton County receives approximately 22.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Snapdragon during the growing season.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Benton County, WA (Zone 7b) Long season
207 days
Last Spring Frost April 3
207 growing days
First Fall Frost October 27
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Benton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.3

Drainage

Well Drained

Snapdragon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (51 days to spare)
Start indoors: Jan 13 Transplant: Mar 17 🌸 Bloom: May 26 – Sep 1
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Jan 23 Transplant: Mar 27 🌸 Bloom: Jun 5 – Sep 11
Safe Start (90%) ✓ Fits season (43 days to spare)
Start indoors: Feb 9 Transplant: Apr 13 🌸 Bloom: Jun 22 – Sep 28

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 Benton County

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

Soil pH

Your soil pH (5.5–6.3) is more acidic than Snapdragon prefers (6.2–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.6%) — Snapdragon will thrive.

How to Plant Snapdragon

9"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Snapdragon

3
successive plantings in your 207-day season

Sow every 8 weeks. Last sowing by Jul 19 to harvest before frost.

For a dedicated fall crop, sow by Sep 01.

Snapdragon Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 1,001 gal / 100 sq ft

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 3.2" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2.1" 0" ❄️ Dormant
Apr 4.3" 1.5" 2.8" 🚿 Regular watering
May 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 0.9" 3.4" 🚿 Regular watering
Jul 4.3" 0.4" 3.9" 🚿 Regular watering
Aug 4.3" 0.4" 3.9" 🚿 Regular watering
Sep 4.3" 0.8" 3.5" 🚿 Regular watering
Oct 4.3" 2" 2.3" 🚿 Regular watering
Nov 3.7" 0" ❄️ Dormant
Dec 3.5" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Benton 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 ~1,360 GDD — county provides 3,312 GDD Excellent fit

Snapdragon Planting Timeline — Benton County, WA

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors January 23 Jan 23 – Feb 6
Transplant Outdoors March 27 Mar 27 – Apr 10
Direct Sow March 6 Mar 6 – Mar 27
Bloom June 5 Jun 5 – Sep 11
Fall Sowing September 1 Sep 1 – Sep 15

· 9" apart · Rows 12" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 7b

📆 Growing Season

207 days in Benton County

Growing Tips for Snapdragon in Benton County

Direct sow Snapdragon outdoors after April 03 in Benton County when soil has warmed and frost danger has passed.

Benton County receives only 22" 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 Benton County, WA?

Benton County is in Zone 7b with an average last frost of April 3. Plan your Snapdragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Benton County, WA?

Benton County, Washington is in USDA Hardiness Zone 7b. The average last spring frost is April 3 and first fall frost is October 27.

🌱

Your Benton County Garden Planner — Free

A 22-page printable planner built for Benton County (Zone 7b). 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 Benton County, WA. 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.