When to plant Rhubarb in Webster County, IA
Webster County's short 161-day growing season means one Rhubarb planting between May 19 and June 2. No fall crop in Zone 5a.
When to Plant Rhubarb in Webster County, IA
Your July game plan for Webster County, Iowa
If you only do a handful of things in the garden this July, make it these. They're sequenced around your zone's frost timing.
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.
Webster County, Iowa is in USDA Zone 5a. The average last spring frost is April 28 and the first fall frost is October 6, giving you a growing season of approximately 161 days.
At an elevation of 1,065 feet, Webster County receives approximately 30.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Rhubarb to ensure they mature before fall.
Webster County Soil Profile
Soil Type
Silt Loam
Soil pH
6.2-7.3
Drainage
Well Drained
Rhubarb 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 Webster County
How your county's soil matches Rhubarb's growing requirements.
Soil pH
Your soil pH (6.2–7.3) overlaps with Rhubarb's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Webster County is excellent for Rhubarb — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Rhubarb.
Organic Matter
Organic matter is excellent (4.4%) — Rhubarb will thrive.
How to Plant Rhubarb
Rhubarb 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| May | 4.3" | 3.4" | 0.9" | 💧 Light watering |
| Jun | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Jul | 4.3" | 3.1" | 1.2" | 💧 Light watering |
| Aug | 4.3" | 3" | 1.3" | 💧 Light watering |
| Sep | 4.3" | 3.2" | 1.1" | 💧 Light watering |
| Oct | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Webster 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 — Webster County, IA
Rhubarb Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 19 | May 19 – Jun 2 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | Transplant Outdoors |
| July | — |
| 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 5a
📆 Growing Season
161 days in Webster County
Growing Tips for Rhubarb in Webster County
Direct sow Rhubarb outdoors after April 28 in Webster County when soil has warmed and frost danger has passed.
Your 161.0-day growing season in Webster County is tight for Rhubarb (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.
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 Webster County, IA?
Webster County is in Zone 5a with an average last frost of April 28. Plan your Rhubarb planting based on this frost date — see the calendar above for exact timing.
What planting zone is Webster County, IA?
Webster County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 28 and first fall frost is October 6.
When should I plant Rhubarb in Webster County, IA?
In Webster County, IA, plant Rhubarb after the last frost (around April 28) and before the first frost (around October 6). Best results when soil holds above 50°F.
What growing zone is Webster County, IA for Rhubarb?
Webster County sits in USDA Zone 5a. Rhubarb grows reliably in zones 3a through 8b, so it's a good fit here.
Can Rhubarb grow in Webster County's climate?
Yes — Rhubarb grows well in Webster County's temperate climate. Webster County averages a 161-day frost-free season, with last frost around April 28 and first frost around October 6.
Your Webster County Garden Planner — Free
A 22-page printable planner built for Webster 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.