When to plant Daffodils in Summit County, CO
For Daffodils in Summit County, the safe spring window opens around mid-spring and closes around late spring. Last expected frost is June 16, first fall frost September 4, giving a 80-day growing season. A second sowing from July 24 to August 7 extends the harvest into fall.
When to Plant Daffodils in Summit County, CO
Summit County, Colorado gardeners: here's your July plan
July rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Summit County, Colorado.
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Plant your fall garden: daffodils
Mid-season soil is hot. Sow a bit deeper than the packet suggests to find cooler, damper ground.
Daffodils (Narcissus spp.) are among the most dependable and longest-lived of all spring bulbs. Their cheerful yellow and white blooms emerge in early spring, often while frost is still possible, bringing color weeks before most other flowers. Unlike tulips, established clumps naturalize readily — spreading and returning reliably year after year without replanting. Deer and rodents avoid them due to toxic alkaloids in the bulb and sap, making them a low-maintenance choice for naturalized areas, woodland edges, and mixed borders.
Summit County, Colorado is in USDA Zone 5a. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.
At an elevation of 7,005 feet, Summit County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Daffodils to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Daffodils successfully. Mulch heavily to conserve soil moisture.
Summit County Soil Profile
Soil Type
Loam
Soil pH
6.8-8
Drainage
Well Drained
Daffodils Planting Risk Windows
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 Summit County
How your county's soil matches Daffodils's growing requirements.
Soil pH
Your soil pH (6.8–8.0) is more alkaline than Daffodils prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Summit County is excellent for Daffodils — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Daffodils.
Organic Matter
Organic matter is moderate (2.1%). Annual compost additions will help Daffodils.
How to Plant Daffodils
Fall planting: Sow 6 weeks before your first frost date for a fall harvest.
Succession Planting Daffodils
Sow every 2.3 weeks. Last sowing by Jul 26 to harvest before frost.
For a dedicated fall crop, sow by Jul 24.
Daffodils Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Daffodils
Daffodils 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 | Daffodils Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.6" | 0" | ❄️ Dormant |
| Apr | — | 1.7" | 0" | ❄️ Dormant |
| May | — | 1.8" | 0" | ❄️ Dormant |
| Jun | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Jul | 2.2" | 1.5" | 0.7" | 💧 Light watering |
| Aug | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Sep | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Oct | — | 1.6" | 0" | ❄️ Dormant |
| Nov | — | 1.2" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Summit County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Daffodils 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.
Daffodils Planting Timeline — Summit County, CO
Daffodils Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Bloom | June 12 | Jun 12 – Jul 3 |
| Fall Sowing | July 24 | Jul 24 – Aug 7 |
Plant 7" deep · 7" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
20–40 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5a
📆 Growing Season
80 days in Summit County
Growing Tips for Daffodils in Summit County
Direct sow Daffodils outdoors after June 16 in Summit County when soil has warmed and frost danger has passed.
Common pests for Daffodils in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
Summit County receives only 18" of rain annually. Daffodils 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 6–8 inches apart in well-drained soil. Allow 12–16 weeks of cold dormancy for proper vernalization. Do not cut back foliage until it turns yellow (6–8 weeks after bloom) — the dying leaves photosynthesize energy into the bulb for next year. Lift and divide overcrowded clumps every 4–5 years in summer after foliage dies back. In zones 7b–9b, select heat-tolerant cultivars (Jonquilla, Tazetta, and Cyclamineus divisions) that perform better with less chill than large-cupped types. Zones 10+: insufficient winter cold; pre-chilling is required but results inconsistent — not recommended for outdoor culture.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Daffodils in Other Locations
Frequently Asked Questions
When should I plant Daffodils in Summit County, CO?
Summit County is in Zone 5a with an average last frost of June 16. Plan your Daffodils planting based on this frost date — see the calendar above for exact timing.
What planting zone is Summit County, CO?
Summit County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 16 and first fall frost is September 4.
When should I plant Daffodils in Summit County, CO?
In Summit County, CO, plant Daffodils after the last frost (around June 16) and before the first frost (around September 4). Best results when soil holds above 50°F.
What growing zone is Summit County, CO for Daffodils?
Summit County sits in USDA Zone 5a. Daffodils grows reliably in zones 3a through 9b, so it's a good fit here.
Can Daffodils grow in Summit County's climate?
Yes — Daffodils grows well in Summit County's temperate climate. Summit County averages a 80-day frost-free season, with last frost around June 16 and first frost around September 4.
Your Summit County Garden Planner — Free
A 22-page printable planner built for Summit 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.