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When to Plant Broccoli Rabe in Kittitas County, WA

Kittitas County, Washington Zone 7a May

Top priorities for Kittitas County, Washington gardeners in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 7
Avg. first frost October 2
Soil temp (4") 58°F
Watering Critical
Pest pressure Low
Daylight 14.9 hrs
  1. Set out broccoli rabe seedlings

    Frost risk is low now in Kittitas County, Washington. If you've been covering beds overnight, you can stop.

Coming up in June — start thinking about
  • Starting indoors: broccoli rabe
  • First harvests: broccoli rabe

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Broccoli rabe (rapini) is a brassica grown for its slightly bitter, nutty-flavored florets, leaves, and stems. It is a staple in Italian cooking.

Kittitas County, Washington is in USDA Zone 7a. The average last spring frost is May 7 and the first fall frost is October 2, giving you a growing season of approximately 148 days.

At an elevation of 2,468 feet, Kittitas County receives approximately 18.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Broccoli Rabe during the growing season. With low rainfall, drip irrigation is essential for growing Broccoli Rabe successfully. Mulch heavily to conserve soil moisture.

Kittitas County, WA (Zone 7a) Short season
148 days
Last Spring Frost May 7
148 growing days
First Fall Frost October 2
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Kittitas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.5-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (73 days to spare)
Start indoors: Mar 26 Transplant: Apr 30 🍅 Harvest: Jun 11 – Jul 16
Recommended (50%) ✓ Fits season (71 days to spare)
Start indoors: Apr 2 Transplant: May 7 🍅 Harvest: Jun 18 – Jul 23
Safe Start (90%) ✓ Fits season (73 days to spare)
Start indoors: Apr 19 Transplant: May 24 🍅 Harvest: Jul 5 – Aug 9

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 Kittitas County

How your county's soil matches Broccoli Rabe's growing requirements.

Soil pH

Your soil pH (5.5–6.7) overlaps with Broccoli Rabe's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Kittitas County is excellent for Broccoli Rabe — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.4%) — Broccoli Rabe will thrive.

How to Plant Broccoli Rabe

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Broccoli Rabe

4
successive plantings in your 148-day season

Sow every 4.6 weeks. Last sowing by Aug 03 to harvest before frost.

For a dedicated fall crop, sow by Jul 24.

Plant Water Budget

Plant needs
0.8″/week
Rainfall provides
0.5″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 417 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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" 0" ❄️ Dormant
Mar 1.8" 0" ❄️ Dormant
Apr 1.7" 0" ❄️ Dormant
May 3.5" 1.2" 2.3" 🚿 Regular watering
Jun 3.5" 0.8" 2.7" 🚿 Regular watering
Jul 3.5" 0.3" 3.2" 🚿 Regular watering
Aug 3.5" 0.4" 3.1" 🚿 Regular watering
Sep 3.5" 0.8" 2.7" 🚿 Regular watering
Oct 3.5" 1.7" 1.8" 🚿 Regular watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Kittitas 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 needs ~875 GDD — county provides 2,590 GDD Excellent fit

Broccoli Rabe Planting Timeline — Kittitas County, WA

Broccoli Rabe Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors May 7 May 7 – May 21
Direct Sow April 23 Apr 23 – May 14
Harvest June 18 Jun 18 – Jul 23
Fall Sowing July 24 Jul 24 – Aug 7

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors Direct Sow
May Transplant Outdoors Direct Sow
June Harvest
July Fall Sowing Harvest
August Fall Sowing
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.8"/week · 1-2 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

148 days in Kittitas County

Growing Tips for Broccoli Rabe in Kittitas County

Direct sow Broccoli Rabe outdoors after May 07 in Kittitas County when soil has warmed and frost danger has passed.

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

  • Strawberries

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Broccoli Rabe in Kittitas County, WA?

Kittitas County is in Zone 7a with an average last frost of May 7. Plan your Broccoli Rabe planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kittitas County, WA?

Kittitas County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is May 7 and first fall frost is October 2.

🌱

Your Kittitas County Garden Planner — Free

A 24-page printable planner built for Kittitas 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Kittitas County, WA. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.