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When to plant Snapdragon in Modoc County, CA

Modoc County's short 113-day growing season means one Snapdragon planting between May 10 and May 31. No fall crop in Zone 6b.

When to Plant Snapdragon in Modoc County, CA

Modoc County, California Zone 6b June

What to do in June

If you only do a handful of things in the garden this June, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 31
Avg. first frost September 21
Soil temp (4") 68°F
Watering Critical
Pest pressure High
Daylight 15 hrs

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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.

Modoc County, California is in USDA Zone 6b. The average last spring frost is May 31 and the first fall frost is September 21, giving you a growing season of approximately 113 days.

At an elevation of 2,205 feet, Modoc County receives approximately 28.3 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Snapdragon to ensure they mature before fall.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Good for cutting Fragrant
Modoc County, CA (Zone 6b) Short season
113 days
Last Spring Frost May 31
113 growing days
First Fall Frost September 21

Modoc County Soil Profile

Soil Type

Loam

Soil pH

5.9-7.4

Drainage

Well Drained

Snapdragon Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 10 Transplant: May 19 🌸 Bloom: Jul 28 – Oct 13
Recommended (50%) ✗ May not fit
Start indoors: Mar 22 Transplant: May 31 🌸 Bloom: Aug 9 – Oct 25
Safe Start (90%) ✗ May not fit
Start indoors: Apr 10 Transplant: Jun 19 🌸 Bloom: Aug 28 – Nov 13

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 Modoc County

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

Soil pH

Your soil pH (5.9–7.4) overlaps with Snapdragon's range (6.2–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Snapdragon.

Organic Matter

Organic matter is moderate (2.1%). Annual compost additions will help Snapdragon.

How to Plant Snapdragon

9"
Between Plants
12"
Between Rows

Snapdragon Water Budget

Plant needs
1.0″/week
Rainfall provides
1.1″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 299 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 5.6" 0" ❄️ Dormant
Feb 5.8" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 4.3" 0.7" 3.6" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 1.3" 0" ❄️ Dormant
Nov 2.7" 0" ❄️ Dormant
Dec 5.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Modoc 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 ~1,041 GDD — county provides 1,384 GDD Excellent fit

Snapdragon Planting Timeline — Modoc County, CA

Snapdragon Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors May 31 May 31 – Jun 14
Direct Sow May 10 May 10 – May 31
Bloom August 9 Aug 9 – Oct 25

· 9" 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
July
August Bloom
September Bloom
October Bloom
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6.2–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

113 days in Modoc County

Growing Tips for Snapdragon in Modoc County

Direct sow Snapdragon outdoors after May 31 in Modoc County when soil has warmed and frost danger has passed.

Your 113.0-day growing season in Modoc County is tight for Snapdragon (70.0-100.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Modoc County, CA?

Modoc County is in Zone 6b with an average last frost of May 31. Plan your Snapdragon planting based on this frost date — see the calendar above for exact timing.

What planting zone is Modoc County, CA?

Modoc County, California is in USDA Hardiness Zone 6b. The average last spring frost is May 31 and first fall frost is September 21.

When should I plant Snapdragon in Modoc County, CA?

In Modoc County, CA, plant Snapdragon after the last frost (around May 31) and before the first frost (around September 21). Best results when soil holds above 50°F.

What growing zone is Modoc County, CA for Snapdragon?

Modoc 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 Modoc County's climate?

Yes — Snapdragon grows well in Modoc County's temperate climate. Modoc County averages a 113-day frost-free season, with last frost around May 31 and first frost around September 21.

🌱

Your Modoc County Garden Planner — Free

A 22-page printable planner built for Modoc 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 Modoc County, CA. 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.