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When to plant Crocus in Lewis County, ID

Plant Crocus in Lewis County from mid-spring to late spring in spring. Lewis County sits in USDA Zone 6b, with last frost around May 20 and first frost on September 23. A second sowing from August 12 to August 26 extends the harvest into fall.

When to Plant Crocus in Lewis County, ID

Lewis County, Idaho Zone 6b June

June to-do list for Lewis County, Idaho

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Lewis County, Idaho.

Avg. last frost May 20
Avg. first frost September 23
Soil temp (4") 57°F
Watering Critical
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.

Lewis County, Idaho is in USDA Zone 6b. The average last spring frost is May 20 and the first fall frost is September 23, giving you a growing season of approximately 126 days.

At an elevation of 4,861 feet, Lewis County receives approximately 13.5 inches of rainfall annually with predominantly loam soil. Summer highs average 90°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
Lewis County, ID (Zone 6b) Short season
126 days
Last Spring Frost May 20
126 growing days
First Fall Frost September 23

Lewis County Soil Profile

Soil Type

Loam

Soil pH

6.7-8

Drainage

Well Drained

Crocus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (148 days to spare)
Transplant: May 12 🌸 Bloom: Mar 31 – Apr 21
Recommended (50%) ✓ Fits season (147 days to spare)
Transplant: May 20 🌸 Bloom: Apr 8 – Apr 29
Safe Start (90%) ✓ Fits season (143 days to spare)
Transplant: Jun 10 🌸 Bloom: Apr 29 – May 20

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 Lewis County

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

Soil pH

Your soil pH (6.7–8.0) is more alkaline than Crocus prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Crocus.

How to Plant Crocus

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

Fall planting: Sow 6 weeks before your first frost date for a fall harvest.

Succession Planting Crocus

15
successive plantings in your 126-day season

Sow every 1.1 weeks. Last sowing by Sep 03 to harvest before frost.

For a dedicated fall crop, sow by Aug 12.

Crocus Water Budget

Plant needs
0.5″/week
Rainfall provides
0.5″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 67 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — 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" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.4" 0" ❄️ Dormant
May 2.2" 1.7" 0.5" 💧 Light watering
Jun 2.2" 0.8" 1.4" 🚿 Regular watering
Jul 2.2" 1.2" 1" 💧 Light watering
Aug 2.2" 1.4" 0.8" 💧 Light watering
Sep 2.2" 1.2" 1" 💧 Light watering
Oct 1.3" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Lewis 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 ~262 GDD — county provides 2,205 GDD Excellent fit

Crocus Planting Timeline — Lewis County, ID

Crocus Planting Calendar

Activity When Date Range
Bloom July 1 Jul 1 – Jul 22
Fall Sowing August 12 Aug 12 – Aug 26

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Only during dry spells

📅 Days to Maturity

10–20 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 6b

📆 Growing Season

126 days in Lewis County

Growing Tips for Crocus in Lewis County

Direct sow Crocus outdoors after May 20 in Lewis County when soil has warmed and frost danger has passed.

Your generous 126.0-day season in Lewis County allows multiple plantings of Crocus. Sow every 5.0 days for continuous harvest.

Lewis County receives only 14" 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 Lewis County, ID?

Lewis County is in Zone 6b with an average last frost of May 20. Plan your Crocus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lewis County, ID?

Lewis County, Idaho is in USDA Hardiness Zone 6b. The average last spring frost is May 20 and first fall frost is September 23.

When should I plant Crocus in Lewis County, ID?

In Lewis County, ID, plant Crocus after the last frost (around May 20) and before the first frost (around September 23). Best results when soil holds above 50°F.

What growing zone is Lewis County, ID for Crocus?

Lewis County sits in USDA Zone 6b. Crocus grows reliably in zones 3a through 8b, so it's a good fit here.

Can Crocus grow in Lewis County's climate?

Yes — Crocus grows well in Lewis County's temperate climate. Lewis County averages a 126-day frost-free season, with last frost around May 20 and first frost around September 23.

🌱

Your Lewis County Garden Planner — Free

A 22-page printable planner built for Lewis 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 Lewis County, ID. Local conditions may vary. Last updated: June 2026.

Sources & credits

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