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When to plant Tulips in Phillips County, CO

Phillips 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 August 26 to September 9 extends the harvest into fall.

When to Plant Tulips in Phillips County, CO

Phillips County, Colorado Zone 5b June

Your June planting checklist for Phillips County, Colorado

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

Avg. last frost May 4
Avg. first frost October 7
Soil temp (4") 54°F
Watering High
Pest pressure High
Daylight 14.9 hrs

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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.

Phillips County, Colorado is in USDA Zone 5b. The average last spring frost is May 4 and the first fall frost is October 7, giving you a growing season of approximately 156 days.

At an elevation of 5,494 feet, Phillips County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Tulips during the growing season.

Bulb Blooms in Spring Pollinator-friendly Good for cutting
Phillips County, CO (Zone 5b) Moderate season
156 days
Last Spring Frost May 4
156 growing days
First Fall Frost October 7

Phillips County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Tulips Planting Risk Windows

Early Start (70% safe) ✓ Fits season (164 days to spare)
Transplant: Apr 30 🌸 Bloom: Apr 2 – Apr 23
Recommended (50%) ✓ Fits season (163 days to spare)
Transplant: May 4 🌸 Bloom: Apr 6 – Apr 27
Safe Start (90%) ✓ Fits season (158 days to spare)
Transplant: May 19 🌸 Bloom: Apr 21 – May 12

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 Phillips County

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

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Tulips prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Tulips.

Organic Matter

Organic matter is moderate (2.4%). 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

12
successive plantings in your 156-day season

Sow every 1.7 weeks. Last sowing by Sep 07 to harvest before frost.

For a dedicated fall crop, sow by Aug 26.

Tulips Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 136 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 1.5" 0" ❄️ Dormant
Feb 1.3" 0" ❄️ Dormant
Mar 1.6" 0" ❄️ Dormant
Apr 1.9" 0" ❄️ Dormant
May 2.2" 2.8" 0" ✅ Rainfall sufficient
Jun 2.2" 1.5" 0.7" 💧 Light watering
Jul 2.2" 1.6" 0.6" 💧 Light watering
Aug 2.2" 2.5" 0" ✅ Rainfall sufficient
Sep 2.2" 1.7" 0.5" 💧 Light watering
Oct 2.2" 1.8" 0.4" 💧 Light watering
Nov 1.7" 0" ❄️ Dormant
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Phillips 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 ~343 GDD — county provides 2,379 GDD Excellent fit

Tulips Planting Timeline — Phillips County, CO

Tulips Planting Calendar

Activity When Date Range
Bloom July 29 Jul 29 – Aug 19
Fall Sowing August 26 Aug 26 – Sep 9

Plant 8" deep · 5" apart · Rows 6" 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 · Only during dry spells

📅 Days to Maturity

15–30 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5b

📆 Growing Season

156 days in Phillips County

Growing Tips for Tulips in Phillips County

Direct sow Tulips outdoors after May 04 in Phillips County when soil has warmed and frost danger has passed.

Your generous 156.0-day season in Phillips County allows multiple plantings of Tulips. Sow every 7.0 days for continuous harvest.

Phillips County receives only 21" 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 Phillips County, CO?

Phillips County is in Zone 5b with an average last frost of May 4. Plan your Tulips planting based on this frost date — see the calendar above for exact timing.

What planting zone is Phillips County, CO?

Phillips County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 4 and first fall frost is October 7.

When should I plant Tulips in Phillips County, CO?

In Phillips County, CO, plant Tulips after the last frost (around May 4) and before the first frost (around October 7). Best results when soil holds above 50°F.

What growing zone is Phillips County, CO for Tulips?

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

Can Tulips grow in Phillips County's climate?

Yes — Tulips grows well in Phillips County's temperate climate. Phillips County averages a 156-day frost-free season, with last frost around May 4 and first frost around October 7.

🌱

Your Phillips County Garden Planner — Free

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

Sources & credits

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