When to Plant Rosemary in Kittitas County, WA
Your May gardening checklist
Your Kittitas County, Washington garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.
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Get rosemary in the ground
Frost risk is low now in Kittitas County, Washington. If you've been covering beds overnight, you can stop.
Rosemary is an aromatic evergreen shrub with needle-like leaves and a piney, citrus flavor. It is a Mediterranean herb that thrives in warm, dry conditions.
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 Rosemary during the growing season. With low rainfall, drip irrigation is essential for growing Rosemary successfully. Mulch heavily to conserve soil moisture.
Kittitas County Soil Profile
Soil Type
Silt Loam
Soil pH
5.5-6.7
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 Kittitas County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (5.5–6.7) overlaps with Rosemary's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Kittitas County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.4%) — Rosemary will thrive.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by Apr 05 to harvest before frost.
Plant Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Rosemary
Rosemary needs approximately 0.3 inches of water per week (1.3" per month). Here's how your county's rainfall compares month by month.
| Month | Rosemary 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 | 1.3" | 1.2" | 0.1" | 💧 Light watering |
| Jun | 1.3" | 0.8" | 0.5" | 💧 Light watering |
| Jul | 1.3" | 0.3" | 1" | 🚿 Regular watering |
| Aug | 1.3" | 0.4" | 0.9" | 🚿 Regular watering |
| Sep | 1.3" | 0.8" | 0.5" | 💧 Light watering |
| Oct | 1.3" | 1.7" | 0" | ✅ Rainfall sufficient |
| 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.
Rosemary 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.
Rosemary Planting Timeline — Kittitas County, WA
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 14 | May 14 – May 28 |
| Harvest | August 6 | Aug 6 – Dec 24 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | — |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | Harvest |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.3"/week · Natural rainfall sufficient
📅 Days to Maturity
80–180 days
🧪 Soil pH
Needs 6–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 7a
📆 Growing Season
148 days in Kittitas County
Growing Tips for Rosemary in Kittitas County
Direct sow Rosemary outdoors after May 07 in Kittitas County when soil has warmed and frost danger has passed.
Your 148.0-day growing season in Kittitas County is tight for Rosemary (80.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.
General growing tips
Grow in well-drained soil and avoid overwatering. In cold climates, grow in containers and bring indoors for winter. Propagate from stem cuttings for faster results than seed.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Rosemary in Other Locations
Frequently Asked Questions
When should I plant Rosemary in Kittitas County, WA?
Kittitas County is in Zone 7a with an average last frost of May 7. Plan your Rosemary 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.