When to Plant Rhubarb in Lake County, OR
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.
Lake County, Oregon is in USDA Zone 5b. 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 1,236 feet, Lake County receives approximately 12.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Rhubarb during the growing season. With low rainfall, drip irrigation is essential for growing Rhubarb successfully. Mulch heavily to conserve soil moisture.
Lake County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.4
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 Lake County
How your county's soil matches Rhubarb's growing requirements.
Soil pH
Your soil pH (5.7–6.4) overlaps with Rhubarb's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Lake County is excellent for Rhubarb — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Rhubarb will thrive.
How to Plant Rhubarb
Plant Water Budget
Monthly Watering Guide for Rhubarb
Rhubarb needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Rhubarb Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.3" | 0" | ❄️ Dormant |
| Apr | — | 0.8" | 0" | ❄️ Dormant |
| May | — | 0.7" | 0" | ❄️ Dormant |
| Jun | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Jul | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Aug | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Sep | 4.3" | 0.5" | 3.8" | 🚿 Regular watering |
| Oct | — | 1.2" | 0" | ❄️ Dormant |
| Nov | — | 1.9" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Lake County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Rhubarb 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.
Rhubarb Planting Timeline — Lake County, OR
Rhubarb Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | July 7 | Jul 7 – Jul 21 |
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
1"/week · 1-2 times/week
📅 Days to Maturity
365–730 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 5b
📆 Growing Season
83 days in Lake County
Growing Tips for Rhubarb in Lake County
Direct sow Rhubarb outdoors after June 16 in Lake County when soil has warmed and frost danger has passed.
Your 83.0-day growing season in Lake County is tight for Rhubarb (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.
Lake County receives only 13" of rain annually. Rhubarb needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
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
Check more plant combinations with our Companion Planting Checker →
Rhubarb in Other Locations
Frequently Asked Questions
When should I plant Rhubarb in Lake County, OR?
Lake County is in Zone 5b 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 Lake County, OR?
Lake County, Oregon is in USDA Hardiness Zone 5b. The average last spring frost is June 16 and first fall frost is September 7.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Lake County gardeners in Zone 5b organize planting dates, track what's growing, and never miss a planting window.
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