When to Plant Broccoli Rabe in Walla Walla County, WA
Your May game plan for Walla Walla County, Washington
A quick May briefing for Walla Walla County, Washington gardeners — what's urgent, what's next, and what can wait.
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Time to start broccoli rabe inside
Bottom-water once the first true leaves appear — it keeps stems dry and knocks back damping-off.
June will be here before you know it — start on
- First harvests: broccoli rabe
Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.
Walla Walla County, Washington is in USDA Zone 7a. The average last spring frost is April 20 and the first fall frost is October 15, giving you a growing season of approximately 178 days.
At an elevation of 3,151 feet, Walla Walla County receives approximately 23.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Broccoli Rabe during the growing season.
Walla Walla County Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
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 Walla Walla County
How your county's soil matches Broccoli Rabe's growing requirements.
Soil pH
Your soil pH (5.2–6.4) is more acidic than Broccoli Rabe prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Walla Walla County is excellent for Broccoli Rabe — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.2%) — Broccoli Rabe will thrive.
How to Plant Broccoli Rabe
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Broccoli Rabe
Sow every 4.6 weeks. Last sowing by Aug 16 to harvest before frost.
For a dedicated fall crop, sow by Aug 06.
Plant Water Budget
Monthly Watering Guide for Broccoli Rabe
Broccoli Rabe needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Broccoli Rabe Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.9" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | — | 2.3" | 0" | ❄️ Dormant |
| Apr | 3.5" | 1.7" | 1.8" | 🚿 Regular watering |
| May | 3.5" | 1.5" | 2" | 🚿 Regular watering |
| Jun | 3.5" | 1" | 2.5" | 🚿 Regular watering |
| Jul | 3.5" | 0.4" | 3.1" | 🚿 Regular watering |
| Aug | 3.5" | 0.5" | 3" | 🚿 Regular watering |
| Sep | 3.5" | 0.9" | 2.6" | 🚿 Regular watering |
| Oct | 3.5" | 2.2" | 1.3" | 💧 Light watering |
| Nov | — | 3.7" | 0" | ❄️ Dormant |
| Dec | — | 3.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Walla Walla County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Broccoli Rabe 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.
Broccoli Rabe Planting Timeline — Walla Walla County, WA
Broccoli Rabe Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | April 20 | Apr 20 – May 4 |
| Direct Sow | April 6 | Apr 6 – Apr 27 |
| Harvest | June 1 | Jun 1 – Jul 6 |
| Fall Sowing | August 6 | Aug 6 – Aug 20 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors |
| June | Harvest |
| July | Harvest |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Only during dry spells
📅 Days to Maturity
40–60 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 7a
📆 Growing Season
178 days in Walla Walla County
Growing Tips for Broccoli Rabe in Walla Walla County
Direct sow Broccoli Rabe outdoors after April 20 in Walla Walla County when soil has warmed and frost danger has passed.
Your generous 178.0-day season in Walla Walla County allows multiple plantings of Broccoli Rabe. Sow every 20.0 days for continuous harvest.
Common pests for Broccoli Rabe in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in spring or fall. Harvest when small yellow flower buds first appear but before they open. Cut the main shoot first to encourage side shoots.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Broccoli Rabe in Other Locations
Frequently Asked Questions
When should I plant Broccoli Rabe in Walla Walla County, WA?
Walla Walla County is in Zone 7a with an average last frost of April 20. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.
What planting zone is Walla Walla County, WA?
Walla Walla County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 20 and first fall frost is October 15.
Your Walla Walla County Garden Planner — Free
A 24-page printable planner built for Walla Walla County (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.