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When to plant Snapdragon in Greene County, IL

Snapdragon planted in Greene County between March 23 and April 13 matures in 70–100 days — well before the October 21 first frost.

When to Plant Snapdragon in Greene County, IL

Greene County, Illinois Zone 6a July

July in the garden — Greene County, Illinois

We've pulled the most time-sensitive tasks for Greene County, Illinois this July and put them front and centre. Tackle them in order.

Avg. last frost April 13
Avg. first frost October 21
Soil temp (4") 76°F
Watering Low
Pest pressure High
Daylight 14.5 hrs
  1. It's harvest week for 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.

Greene County, Illinois is in USDA Zone 6a. The average last spring frost is April 13 and the first fall frost is October 21, giving you a growing season of approximately 191 days.

At an elevation of 1,248 feet, Greene County receives approximately 37 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Snapdragon during the growing season.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Greene County, IL (Zone 6a) Moderate season
191 days
Last Spring Frost April 13
191 growing days
First Fall Frost October 21

Greene County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Snapdragon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (50 days to spare)
Start indoors: Jan 27 Transplant: Apr 7 🌸 Bloom: Jun 16 – Aug 25
Recommended (50%) ✓ Fits season (51 days to spare)
Start indoors: Feb 2 Transplant: Apr 13 🌸 Bloom: Jun 22 – Aug 31
Safe Start (90%) ✓ Fits season (50 days to spare)
Start indoors: Feb 14 Transplant: Apr 25 🌸 Bloom: Jul 4 – Sep 12

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 Greene County

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

Soil pH

Your soil pH (6.1–6.7) overlaps with Snapdragon's range (6.2–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Snapdragon.

Organic Matter

Organic matter is excellent (4.5%) — Snapdragon will thrive.

How to Plant Snapdragon

9"
Between Plants
12"
Between Rows

Succession Planting Snapdragon

3
successive plantings in your 191-day season

Sow every 8 weeks. Last sowing by Jul 13 to harvest before frost.

Snapdragon Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 992 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 1.6" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.7" 0" ❄️ Dormant
Apr 4.3" 3.2" 1.1" 💧 Light watering
May 4.3" 3.9" 0.4" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.9" 0.4" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3" 1.3" 💧 Light watering
Nov 2.6" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Greene 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 ~1,232 GDD — county provides 2,769 GDD Excellent fit

Snapdragon Planting Timeline — Greene County, IL

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors February 2 Feb 2 – Feb 16
Transplant Outdoors April 13 Apr 13 – Apr 27
Direct Sow March 23 Mar 23 – Apr 13
Bloom June 22 Jun 22 – Aug 31

· 9" apart · Rows 12" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6a

📆 Growing Season

191 days in Greene County

Growing Tips for Snapdragon in Greene County

Direct sow Snapdragon outdoors after April 13 in Greene County when soil has warmed and frost danger has passed.

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 Greene County, IL?

Greene County is in Zone 6a with an average last frost of April 13. Plan your Snapdragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Greene County, IL?

Greene County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 13 and first fall frost is October 21.

When should I plant Snapdragon in Greene County, IL?

In Greene County, IL, plant Snapdragon after the last frost (around April 13) and before the first frost (around October 21). Best results when soil holds above 50°F.

What growing zone is Greene County, IL for Snapdragon?

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

Can Snapdragon grow in Greene County's climate?

Yes — Snapdragon grows well in Greene County's temperate climate. Greene County averages a 191-day frost-free season, with last frost around April 13 and first frost around October 21.

🌱

Your Greene County Garden Planner — Free

A 22-page printable planner built for Greene 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 Greene County, IL. Local conditions may vary. Last updated: July 2026.

Sources & credits

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