Blog

When to plant Hostas in Lake County, CO

Plant Hostas in Lake County, between July 5 and July 19 — the only viable window. Zone 5a's short season (70 frost-free days) rules out a fall crop.

When to Plant Hostas in Lake County, CO

Lake County, Colorado Zone 5a July

Top priorities for Lake County, Colorado gardeners in July

Each item below is timed to Lake County, Colorado's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost June 21
Avg. first frost August 30
Soil temp (4") 52°F
Watering High
Pest pressure High
Daylight 14.5 hrs
  1. Time to transplant hostas

    Your last frost (June 21) has passed. These warm-season crops can handle outdoor soil now.

Get ahead of August
  • Starting indoors: hostas

Instant PDF download. No spam, unsubscribe any time.

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.

Lake County, Colorado is in USDA Zone 5a. The average last spring frost is June 21 and the first fall frost is August 30, giving you a growing season of approximately 70 days.

At an elevation of 7,687 feet, Lake County receives approximately 21.2 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Hostas to ensure they mature before fall.

Perennial Blooms in Summer Pollinator-friendly
Lake County, CO (Zone 5a) Very short season
70 days
Last Spring Frost June 21
70 growing days
First Fall Frost August 30

Lake County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.2

Drainage

Well Drained

Hostas Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 7 Transplant: Jun 30 🌸 Bloom: Sep 22 – Dec 15
Recommended (50%) ✗ May not fit
Start indoors: Apr 12 Transplant: Jul 5 🌸 Bloom: Sep 27 – Dec 20
Safe Start (90%) ✗ May not fit
Start indoors: Apr 18 Transplant: Jul 11 🌸 Bloom: Oct 3 – 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 Lake County

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

Soil pH

Your soil pH (6.6–8.2) overlaps with Hostas's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). 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
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 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 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 2.1" 0" ❄️ Dormant
May 2.7" 0" ❄️ Dormant
Jun 4.3" 1.4" 2.9" 🚿 Regular watering
Jul 4.3" 2.1" 2.2" 🚿 Regular watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 1.6" 0" ❄️ Dormant
Oct 2.1" 0" ❄️ Dormant
Nov 1.6" 0" ❄️ Dormant
Dec 1.2" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Aug in Lake 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 ~919 GDD — county provides 857 GDD Tight fit

Hostas Planting Timeline — Lake County, CO

Hostas Planting Calendar

Activity When Date Range
Start Indoors April 12 Apr 12 – Apr 26
Transplant Outdoors July 5 Jul 5 – Jul 19
Bloom September 27 Sep 27 – Dec 20

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

70 days in Lake County

Growing Tips for Hostas in Lake County

Direct sow Hostas outdoors after June 21 in Lake County when soil has warmed and frost danger has passed.

Your 70.0-day growing season in Lake County is tight for Hostas (60.0-90.0 days to maturity). Start indoors and choose early-maturing varieties.

Lake County receives only 21" 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 Lake County, CO?

Lake County is in Zone 5a with an average last frost of June 21. Plan your Hostas planting based on this frost date — see the calendar above for exact timing.

What planting zone is Lake County, CO?

Lake County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 21 and first fall frost is August 30.

When should I plant Hostas in Lake County, CO?

In Lake County, CO, plant Hostas after the last frost (around June 21) and before the first frost (around August 30). Best results when soil holds above 50°F.

What growing zone is Lake County, CO for Hostas?

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

Can Hostas grow in Lake County's climate?

Yes — Hostas grows well in Lake County's temperate climate. Lake County averages a 70-day frost-free season, with last frost around June 21 and first frost around August 30.

🌱

Your Lake County Garden Planner — Free

A 22-page printable planner built for Lake County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Lake 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.