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When to plant Hostas in Moffat County, CO

In Moffat County, Hostas is a spring-only crop. Plant June 21–July 5 once soil hits 50°F.

When to Plant Hostas in Moffat County, CO

Moffat County, Colorado Zone 5b August

Moffat County, Colorado gardeners: here's your August plan

Here's what deserves your attention in Moffat County, Colorado this month. Everything below is tailored to Zone 5b and timed around your local frost dates.

Avg. last frost June 7
Avg. first frost September 14
Soil temp (4") 60°F
Watering High
Pest pressure High
Daylight 13.6 hrs
  1. Indoor seed-starting week for hostas

    Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.

September will be here before you know it — start on
  • First harvests: hostas

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Hostas (Hosta spp.) are the undisputed kings of the shade garden, grown primarily for their spectacular mounded foliage in shades of deep green, blue-green, gold, and variegated combinations. Originating in East Asia (Japan, China, Korea), hostas form dense, long-lived clumps that reliably return year after year with minimal care. In summer, tall scapes of lavender or white tubular flowers rise above the foliage — some cultivars (notably H. plantaginea hybrids) are notably fragrant. Extremely adaptable in moist, well-drained soil with consistent shade to part shade.

Moffat County, Colorado is in USDA Zone 5b. The average last spring frost is June 7 and the first fall frost is September 14, giving you a growing season of approximately 99 days.

At an elevation of 6,597 feet, Moffat County receives approximately 12.3 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Hostas during the growing season. With low rainfall, drip irrigation is essential for growing Hostas successfully. Mulch heavily to conserve soil moisture.

Perennial Blooms in Summer Pollinator-friendly
Moffat County, CO (Zone 5b) Very short season
99 days
Last Spring Frost June 7
99 growing days
First Fall Frost September 14

Moffat County Soil Profile

Soil Type

Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Hostas Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 19 Transplant: Jun 11 🌸 Bloom: Sep 3 – Dec 3
Recommended (50%) ✗ May not fit
Start indoors: Mar 29 Transplant: Jun 21 🌸 Bloom: Sep 13 – Dec 13
Safe Start (90%) ✗ May not fit
Start indoors: Apr 11 Transplant: Jul 4 🌸 Bloom: Sep 26 – Dec 26

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 Moffat County

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

Soil pH

Your soil pH (6.8–8.3) is more alkaline than Hostas prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Hostas.

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Hostas.

How to Plant Hostas

1"
Planting Depth
24"
Between Plants
30"
Between Rows

Hostas Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 823 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Hostas

Hostas needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Hostas Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 1.4" 0" ❄️ Dormant
Jun 4.3" 0.8" 3.5" 🚿 Regular watering
Jul 4.3" 1" 3.3" 🚿 Regular watering
Aug 4.3" 1.4" 2.9" 🚿 Regular watering
Sep 4.3" 1.1" 3.2" 🚿 Regular watering
Oct 1" 0" ❄️ Dormant
Nov 0.8" 0" ❄️ Dormant
Dec 0.8" 0" ❄️ Dormant

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

Hostas 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.

Hostas needs ~1,088 GDD — county provides 1,435 GDD Excellent fit

Hostas Planting Timeline — Moffat County, CO

Hostas Planting Calendar

Activity When Date Range
Start Indoors March 29 Mar 29 – Apr 12
Transplant Outdoors June 21 Jun 21 – Jul 5
Bloom September 13 Sep 13 – Dec 13

Plant 1" deep · 24" apart · Rows 30" apart

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May
June Transplant Outdoors
July Transplant Outdoors
August
September Bloom
October Bloom
November Bloom
December Bloom

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

99 days in Moffat County

Growing Tips for Hostas in Moffat County

Direct sow Hostas outdoors after June 07 in Moffat County when soil has warmed and frost danger has passed.

Your 99.0-day growing season in Moffat County is tight for Hostas (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

Moffat County receives only 12" of rain annually. Hostas needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant bare-root crowns or divisions in early spring just as new growth emerges, or in fall at least 6 weeks before hard freeze. Choose a site with morning sun and afternoon shade in Zones 6+; deeper shade is acceptable but reduces vigor and bloom. Keep consistently moist but never waterlogged. Apply a 2–3 inch mulch layer to conserve moisture and suppress weeds. Slugs are the primary pest — use iron phosphate bait if damage is significant. Deer will browse hostas heavily in most regions; protect with fencing or repellents. Divide every 3–5 years in spring to rejuvenate. Fall planting (Zones 4+) is equally effective as spring planting when soil stays workable. Year 2+ plants reach full size and flower most reliably; first-year divisions may produce limited flower spikes.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hostas in Moffat County, CO?

Moffat County is in Zone 5b with an average last frost of June 7. Plan your Hostas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Moffat County, CO?

Moffat County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is June 7 and first fall frost is September 14.

When should I plant Hostas in Moffat County, CO?

In Moffat County, CO, plant Hostas after the last frost (around June 7) and before the first frost (around September 14). Best results when soil holds above 50°F.

What growing zone is Moffat County, CO for Hostas?

Moffat County sits in USDA Zone 5b. Hostas grows reliably in zones 3a through 9a, so it's a good fit here.

Can Hostas grow in Moffat County's climate?

Yes — Hostas grows well in Moffat County's temperate climate. Moffat County averages a 99-day frost-free season, with last frost around June 7 and first frost around September 14.

🌱

Your Moffat County Garden Planner — Free

A 22-page printable planner built for Moffat 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 Moffat County, CO. Local conditions may vary. Last updated: August 2026.

Sources & credits

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