When to Plant Rhubarb in Summit County, CO
Rhubarb is a long-lived perennial vegetable grown for its tart, colorful stalks. Only the stalks are edible as the leaves contain toxic oxalic acid.
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 Rhubarb to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Rhubarb 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.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Rhubarb Planting Timeline — Summit County, CO
Rhubarb Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | July 14 | Jul 14 – Jul 28 |
Plant 1" deep · 30" apart · Rows 42" 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
Moderate — regular watering
Days to Maturity
365–730 days
Soil pH
6 – 7
USDA Zone
Zone 4a
Growing Season
80 days
Growing Tips for Summit County
Plant crowns in early spring in rich, well-drained soil. Do not harvest stalks the first year. Pull (do not cut) stalks at harvest to avoid introducing rot.
Companion Planting
Good Companions
Level Up Your Garden
Rhubarb in Other Locations
Frequently Asked Questions
When should I plant Rhubarb in Summit County, CO?
Summit County is in Zone 4a with an average last frost of June 16. Plan your Rhubarb 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.