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When to plant Snapdragon in Teller County, CO

In Teller County, Snapdragon is a single-season spring crop — there's no second fall window. Plant April 27–May 18 for an 70–100-day harvest, finishing well before the October 6 first frost.

When to Plant Snapdragon in Teller County, CO

Teller County, Colorado Zone 5b July

This month in Teller County, Colorado

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

Avg. last frost May 11
Avg. first frost October 6
Soil temp (4") 56°F
Watering High
Pest pressure High
Daylight 14.5 hrs
  1. Time to start snapdragon inside

    Your window is short. These crops want several weeks of indoor growth before they go outside.

  2. Pick snapdragon

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

A few tasks this July that'll pay off in August
  • 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.

Teller County, Colorado is in USDA Zone 5b. The average last spring frost is May 11 and the first fall frost is October 6, giving you a growing season of approximately 148 days.

At an elevation of 6,538 feet, Teller County receives approximately 19.5 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Snapdragon to ensure they mature before fall. 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
Teller County, CO (Zone 5b) Short season
148 days
Last Spring Frost May 11
148 growing days
First Fall Frost October 6

Teller County Soil Profile

Soil Type

Loam

Soil pH

6.4-8.1

Drainage

Well Drained

Snapdragon Planting Risk Windows

Early Start (70% safe) ✓ Fits season (6 days to spare)
Start indoors: Feb 23 Transplant: May 4 🌸 Bloom: Jul 13 – Sep 21
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Mar 2 Transplant: May 11 🌸 Bloom: Jul 20 – Sep 28
Safe Start (90%) ✓ Fits season (3 days to spare)
Start indoors: Mar 18 Transplant: May 27 🌸 Bloom: Aug 5 – Oct 14

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 Teller County

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

Soil pH

Your soil pH (6.4–8.1) is more alkaline than Snapdragon prefers (6.2–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Teller 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 148-day season

Sow every 8 weeks. Last sowing by Jun 28 to harvest before frost.

Snapdragon Water Budget

Plant needs
1.0″/week
Rainfall provides
0.6″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 706 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 1.3" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.9" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 2.4" 1.9" 💧 Light watering
Jun 4.3" 1.3" 3" 🚿 Regular watering
Jul 4.3" 1.5" 2.8" 🚿 Regular watering
Aug 4.3" 1.7" 2.6" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 1.9" 2.4" 🚿 Regular watering
Nov 1.3" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Teller 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 ~1,105 GDD — county provides 1,924 GDD Excellent fit

Snapdragon Planting Timeline — Teller County, CO

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 11 May 11 – May 25
Direct Sow April 27 Apr 27 – May 18
Bloom July 20 Jul 20 – Sep 28

· 9" apart · Rows 12" apart

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 5b

📆 Growing Season

148 days in Teller County

Growing Tips for Snapdragon in Teller County

Direct sow Snapdragon outdoors after May 11 in Teller County when soil has warmed and frost danger has passed.

Teller County receives only 20" 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 Teller County, CO?

Teller County is in Zone 5b with an average last frost of May 11. Plan your Snapdragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Teller County, CO?

Teller County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 11 and first fall frost is October 6.

When should I plant Snapdragon in Teller County, CO?

In Teller County, CO, plant Snapdragon after the last frost (around May 11) and before the first frost (around October 6). Best results when soil holds above 50°F.

What growing zone is Teller County, CO for Snapdragon?

Teller County sits in USDA Zone 5b. Snapdragon grows reliably in zones 2a through 11b, so it's a good fit here.

Can Snapdragon grow in Teller County's climate?

Yes — Snapdragon grows well in Teller County's temperate climate. Teller County averages a 148-day frost-free season, with last frost around May 11 and first frost around October 6.

🌱

Your Teller County Garden Planner — Free

A 22-page printable planner built for Teller County (Zone 5b). 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 Teller County, CO. Local conditions may vary. Last updated: July 2026.

Sources & credits

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