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When to plant Crocus in Clearwater County, ID

Crocus planted in Clearwater County between mid-spring and late spring matures in 10–20 days — well before the September 28 first frost. A second sowing from August 24 to September 7 extends the harvest into fall.

When to Plant Crocus in Clearwater County, ID

Clearwater County, Idaho Zone 7a June

Your June planting checklist for Clearwater County, Idaho

Welcome to June in Zone 7a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 17
Avg. first frost September 28
Soil temp (4") 44°F
Watering High
Pest pressure High
Daylight 15.6 hrs

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Crocuses (Crocus spp.) are the heralds of spring — small, gem-like blooms that push up through frozen ground or even snow, often weeks before any other flower. Their compact corms naturalize readily in lawns, rock gardens, and borders, creating drifts of purple, white, and yellow that expand year after year. Bees prize early crocus as one of their first nectar and pollen sources of the season. The saffron crocus (C. sativus) blooms in fall and yields the world's most expensive spice.

Clearwater County, Idaho is in USDA Zone 7a. The average last spring frost is May 17 and the first fall frost is September 28, giving you a growing season of approximately 134 days.

At an elevation of 7,800 feet, Clearwater County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Crocus during the growing season. With low rainfall, drip irrigation is essential for growing Crocus successfully. Mulch heavily to conserve soil moisture.

Bulb Blooms in Spring Pollinator-friendly Fragrant
Clearwater County, ID (Zone 7a) Short season
134 days
Last Spring Frost May 17
134 growing days
First Fall Frost September 28

Clearwater County Soil Profile

Soil Type

Loam

Soil pH

6.5-8.1

Drainage

Well Drained

Crocus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (148 days to spare)
Transplant: May 8 🌸 Bloom: Apr 3 – Apr 24
Recommended (50%) ✓ Fits season (148 days to spare)
Transplant: May 17 🌸 Bloom: Apr 12 – May 3
Safe Start (90%) ✓ Fits season (155 days to spare)
Transplant: Jun 10 🌸 Bloom: May 6 – May 27

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 Clearwater County

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

Soil pH

Your soil pH (6.5–8.1) is more alkaline than Crocus prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.8%). Annual compost additions will help Crocus.

How to Plant Crocus

4"
Planting Depth
3"
Between Plants
4"
Between Rows

Fall planting: Sow 5 weeks before your first frost date for a fall harvest.

Succession Planting Crocus

16
successive plantings in your 134-day season

Sow every 1.1 weeks. Last sowing by Sep 08 to harvest before frost.

For a dedicated fall crop, sow by Aug 24.

Crocus Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Crocus

Crocus needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Crocus Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.2" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 2.2" 2.2" 0" ✅ Rainfall sufficient
Jun 2.2" 1.3" 0.9" 💧 Light watering
Jul 2.2" 1.8" 0.4" 💧 Light watering
Aug 2.2" 2" 0.2" 💧 Light watering
Sep 2.2" 1.5" 0.7" 💧 Light watering
Oct 1.8" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

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

Crocus 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.

Crocus needs ~229 GDD — county provides 2,043 GDD Excellent fit

Crocus Planting Timeline — Clearwater County, ID

Crocus Planting Calendar

Activity When Date Range
Bloom July 20 Jul 20 – Aug 10
Fall Sowing August 24 Aug 24 – Sep 7

Plant 4" deep · 3" apart · Rows 4" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June
July Bloom
August Fall Sowing Bloom
September Fall Sowing
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

10–20 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7a

📆 Growing Season

134 days in Clearwater County

Growing Tips for Crocus in Clearwater County

Direct sow Crocus outdoors after May 17 in Clearwater County when soil has warmed and frost danger has passed.

Your generous 134.0-day season in Clearwater County allows multiple plantings of Crocus. Sow every 5.0 days for continuous harvest.

Clearwater County receives only 19" of rain annually. Crocus needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant corms 3–4 inches deep and 2–3 inches apart in fall, when soil temperature drops below 60°F. Mass plantings (at least 25 corms per cluster) create the most visual impact. Plant in well-drained soil — corms rot in standing water. Crocus naturalize well under deciduous trees; the tree leafs out after crocus dormancy begins, so light competition is minimal. Squirrels and chipmunks dig corms — plant deeper (4 inches) or use wire mesh baskets in high-predation areas. Allow foliage to die back naturally before mowing lawns. In zones 8a–8b, plant in December with pre-chilled corms for best results.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Crocus in Clearwater County, ID?

Clearwater County is in Zone 7a with an average last frost of May 17. Plan your Crocus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Clearwater County, ID?

Clearwater County, Idaho is in USDA Hardiness Zone 7a. The average last spring frost is May 17 and first fall frost is September 28.

When should I plant Crocus in Clearwater County, ID?

In Clearwater County, ID, plant Crocus after the last frost (around May 17) and before the first frost (around September 28). Best results when soil holds above 50°F.

What growing zone is Clearwater County, ID for Crocus?

Clearwater County sits in USDA Zone 7a. Crocus grows reliably in zones 3a through 8b, so it's a good fit here.

Can Crocus grow in Clearwater County's climate?

Yes — Crocus grows well in Clearwater County's temperate climate. Clearwater County averages a 134-day frost-free season, with last frost around May 17 and first frost around September 28.

🌱

Your Clearwater County Garden Planner — Free

A 22-page printable planner built for Clearwater County (Zone 7a). 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 Clearwater County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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