When to Plant Napa Cabbage in Keokuk County, IA
May to-do list for Keokuk County, Iowa
Here's what deserves your attention in Keokuk County, Iowa this month. Everything below is tailored to Zone 5b and timed around your local frost dates.
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Start napa cabbage under lights
You're about 20 weeks out from your last frost — the perfect window to get these germinating indoors.
June prep starts now
- First harvests: napa cabbage
Napa cabbage forms tall, barrel-shaped heads with tender, crinkled leaves and a mild, slightly sweet flavor. It is the primary cabbage used for kimchi.
Keokuk County, Iowa is in USDA Zone 5b. The average last spring frost is April 23 and the first fall frost is October 12, giving you a growing season of approximately 172 days.
At an elevation of 654 feet, Keokuk County receives approximately 41.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Napa Cabbage to ensure they mature before fall.
Keokuk County Soil Profile
Soil Type
Silt Loam
Soil pH
6-6.7
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 Keokuk County
How your county's soil matches Napa Cabbage's growing requirements.
Soil pH
Your soil pH (6.0–6.7) is within Napa Cabbage's preferred range (6.0–7.5).
Soil Texture
The silt loam soil in Keokuk County is excellent for Napa Cabbage — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.0%) — Napa Cabbage will thrive.
How to Plant Napa Cabbage
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Napa Cabbage
Sow every 6.3 weeks. Last sowing by Jul 29 to harvest before frost.
For a dedicated fall crop, sow by Aug 03.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Napa Cabbage
Napa Cabbage needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Napa Cabbage Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.7" | 0" | ❄️ Dormant |
| Mar | — | 2.6" | 0" | ❄️ Dormant |
| Apr | 6.5" | 4.3" | 2.2" | 💧 Light watering |
| May | 6.5" | 4.9" | 1.6" | 💧 Light watering |
| Jun | 6.5" | 5.7" | 0.8" | 💧 Light watering |
| Jul | 6.5" | 4.2" | 2.3" | 💧 Light watering |
| Aug | 6.5" | 4.4" | 2.1" | 💧 Light watering |
| Sep | 6.5" | 3.8" | 2.7" | 💧 Light watering |
| Oct | 6.5" | 3.4" | 3.1" | 💧 Light watering |
| Nov | — | 2.7" | 0" | ❄️ Dormant |
| Dec | — | 2.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Keokuk County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Napa Cabbage 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.
Napa Cabbage Planting Timeline — Keokuk County, IA
Napa Cabbage Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 19 | Mar 19 – Apr 2 |
| Transplant Outdoors | April 23 | Apr 23 – May 7 |
| Direct Sow | April 9 | Apr 9 – Apr 30 |
| Harvest | June 18 | Jun 18 – Jul 23 |
| Fall Sowing | August 3 | Aug 3 – Aug 17 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1.5"/week · 1-2 times/week
📅 Days to Maturity
55–75 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 5b
📆 Growing Season
172 days in Keokuk County
Growing Tips for Napa Cabbage in Keokuk County
Direct sow Napa Cabbage outdoors after April 23 in Keokuk County when soil has warmed and frost danger has passed.
Common pests for Napa Cabbage in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Best grown as a fall crop. Direct sow in late summer, 60-70 days before first frost. Keep soil evenly moist. Bolt-resistant varieties are available for spring planting.
Companion Planting
Good Companions
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Check more plant combinations with our Companion Planting Checker →
Napa Cabbage in Other Locations
Frequently Asked Questions
When should I plant Napa Cabbage in Keokuk County, IA?
Keokuk County is in Zone 5b with an average last frost of April 23. Plan your Napa Cabbage planting based on this frost date — see the calendar above for exact timing.
What planting zone is Keokuk County, IA?
Keokuk County, Iowa is in USDA Hardiness Zone 5b. The average last spring frost is April 23 and first fall frost is October 12.
Your Keokuk County Garden Planner — Free
A 24-page printable planner built for Keokuk County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.