When to Plant Blueberries in Summit County, CO
Blueberries are long-lived shrubs producing sweet, antioxidant-rich berries. They require acidic soil and are attractive ornamental plants with fall color and spring flowers.
Summit County, Colorado is in USDA Zone 4a. 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 Blueberries to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Blueberries successfully. Mulch heavily to conserve soil moisture.
Summit County Soil Profile
Soil Type
Loam
Soil pH
6.8-8
Drainage
Well Drained
Plant 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 Blueberries's growing requirements.
Soil pH
Your soil pH (6.8–8.0) is more alkaline than Blueberries prefers (4.5–5.5). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Summit County is excellent for Blueberries — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Blueberries.
Organic Matter
Organic matter is moderate (2.1%). Annual compost additions will help Blueberries.
How to Plant Blueberries
How Much Blueberries to Grow
For a family of 4, plant approximately 8 blueberries plants in about 192 sq ft. In Summit County's 80-day season, you'll have plenty of time for a full harvest. Plan your garden layout →
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Blueberries
Blueberries needs approximately 1.2 inches of water per week (5.2" per month). Here's how your county's rainfall compares month by month.
| Month | Blueberries 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 | 5.2" | 1.3" | 3.9" | 🚿 Regular watering |
| Jul | 5.2" | 1.5" | 3.7" | 🚿 Regular watering |
| Aug | 5.2" | 1.9" | 3.3" | 🚿 Regular watering |
| Sep | 5.2" | 1.3" | 3.9" | 🚿 Regular 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.
Blueberries 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.
Blueberries Planting Timeline — Summit County, CO
Blueberries Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | July 14 | Jul 14 – Jul 28 |
· 48" apart · Rows 72" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | — |
| June | — |
| July | Transplant Outdoors |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.2"/week · 2-3 times/week
📅 Days to Maturity
730–1095 days
🧪 Soil pH
Needs 4.5–5.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 4a
📆 Growing Season
80 days in Summit County
Growing Tips for Blueberries in Summit County
Direct sow Blueberries outdoors after June 16 in Summit County when soil has warmed and frost danger has passed.
Your 80.0-day growing season in Summit County is tight for Blueberries (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.
Summit County receives only 18" of rain annually. Blueberries needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Plant at least two varieties for cross-pollination. Acidify soil with sulfur or pine needle mulch to maintain pH 4.5-5.5. Protect ripening berries from birds with netting.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Blueberries in Other Locations
Frequently Asked Questions
When should I plant Blueberries in Summit County, CO?
Summit County is in Zone 4a with an average last frost of June 16. Plan your Blueberries 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 4a. The average last spring frost is June 16 and first fall frost is September 4.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Summit County gardeners in Zone 4a organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.