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When to plant Tulips in Pitkin County, CO

Pitkin County's spring Tulips window runs mid-spring through late spring. time plantings around the expected last-frost window for best survival. A second sowing from July 27 to August 10 extends the harvest into fall.

When to Plant Tulips in Pitkin County, CO

Pitkin County, Colorado Zone 5a July

July to-do list for Pitkin County, Colorado

July is a pivotal month for Pitkin County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 16
Avg. first frost September 7
Soil temp (4") 53°F
Watering High
Pest pressure High
Daylight 14.5 hrs
  1. Get tulips in for a late-season harvest

    A row cover ready in the garage extends your harvest by weeks once the nights turn cold.

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Tulips (Tulipa spp.) are the quintessential spring bulb, producing their iconic cup-shaped blooms in virtually every color from pure white to near-black. Fall-planted and cold-dependent, they emerge in early spring before most other flowers, providing weeks of bold color at a time when gardens are just waking up. Hundreds of cultivars span early-, mid-, and late-season types, extending the display across six weeks when planted in succession.

Pitkin County, Colorado is in USDA Zone 5a. The average last spring frost is June 16 and the first fall frost is September 7, giving you a growing season of approximately 83 days.

At an elevation of 6,411 feet, Pitkin County receives approximately 17.8 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Tulips to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Tulips successfully. Mulch heavily to conserve soil moisture.

Bulb Blooms in Spring Pollinator-friendly Good for cutting
Pitkin County, CO (Zone 5a) Very short season
83 days
Last Spring Frost June 16
83 growing days
First Fall Frost September 7

Pitkin County Soil Profile

Soil Type

Loam

Soil pH

6.6-8.3

Drainage

Well Drained

Tulips Planting Risk Windows

Early Start (70% safe) ✓ Fits season (90 days to spare)
Transplant: Jun 5 🌸 Bloom: May 8 – May 29
Recommended (50%) ✓ Fits season (90 days to spare)
Transplant: Jun 16 🌸 Bloom: May 19 – Jun 9
Safe Start (90%) ✓ Fits season (109 days to spare)
Transplant: Jun 27 🌸 Bloom: May 30 – Jun 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 Pitkin County

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

Soil pH

Your soil pH (6.6–8.3) is more alkaline than Tulips prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Tulips.

How to Plant Tulips

8"
Planting Depth
5"
Between Plants
6"
Between Rows

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

Succession Planting Tulips

6
successive plantings in your 83-day season

Sow every 1.7 weeks. Last sowing by Aug 08 to harvest before frost.

For a dedicated fall crop, sow by Jul 27.

Tulips Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/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 Tulips

Tulips 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 Tulips Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 2" 0" ❄️ Dormant
Jun 2.2" 1.3" 0.9" 💧 Light watering
Jul 2.2" 1.4" 0.8" 💧 Light watering
Aug 2.2" 1.9" 0.3" 💧 Light watering
Sep 2.2" 1.7" 0.5" 💧 Light watering
Oct 1.5" 0" ❄️ Dormant
Nov 1.1" 0" ❄️ Dormant
Dec 0.9" 0" ❄️ Dormant

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

Tulips 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.

Tulips needs ~259 GDD — county provides 954 GDD Excellent fit

Tulips Planting Timeline — Pitkin County, CO

Tulips Planting Calendar

Activity When Date Range
Bloom June 29 Jun 29 – Jul 20
Fall Sowing July 27 Jul 27 – Aug 10

Plant 8" deep · 5" apart · Rows 6" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

15–30 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

83 days in Pitkin County

Growing Tips for Tulips in Pitkin County

Direct sow Tulips outdoors after June 16 in Pitkin County when soil has warmed and frost danger has passed.

Your generous 83.0-day season in Pitkin County allows multiple plantings of Tulips. Sow every 7.0 days for continuous harvest.

Pitkin County receives only 18" of rain annually. Tulips needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant bulbs pointed-end up in fall, 6–8 inches deep and 4–6 inches apart, in well-drained soil. Tulips require 12–16 weeks of cold at 35–45°F for proper vernalization — they fail to bloom without it. In zones 7–8b, plant bulbs a few weeks later than further north (late November) to ensure cold-soil uptake before spring warmth. Lift and discard bulbs after bloom in zones 7b+, as heat prevents reliable repeat flowering; treat them as annuals. Allow foliage to die back naturally before removing — it feeds next year's bulb (if leaving in the ground). Do not overwater; excellent drainage is essential to prevent bulb rot. Zones 9+: outdoor culture is not recommended; pre-chilling in the refrigerator is required and results are inconsistent.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Tulips in Pitkin County, CO?

Pitkin County is in Zone 5a with an average last frost of June 16. Plan your Tulips planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pitkin County, CO?

Pitkin County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 16 and first fall frost is September 7.

When should I plant Tulips in Pitkin County, CO?

In Pitkin County, CO, plant Tulips after the last frost (around June 16) and before the first frost (around September 7). Best results when soil holds above 50°F.

What growing zone is Pitkin County, CO for Tulips?

Pitkin County sits in USDA Zone 5a. Tulips grows reliably in zones 3a through 8b, so it's a good fit here.

Can Tulips grow in Pitkin County's climate?

Yes — Tulips grows well in Pitkin County's temperate climate. Pitkin County averages a 83-day frost-free season, with last frost around June 16 and first frost around September 7.

🌱

Your Pitkin County Garden Planner — Free

A 22-page printable planner built for Pitkin 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.

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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 Pitkin 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.