When to Plant Rosemary in Lewis County, WA
This month in Lewis County, Washington
A quick May briefing for Lewis County, Washington gardeners — what's urgent, what's next, and what can wait.
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Move rosemary from tray to bed
Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.
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.
Lewis County, Washington is in USDA Zone 8a. The average last spring frost is April 25 and the first fall frost is October 24, giving you a growing season of approximately 182 days.
At an elevation of 327 feet, Lewis County receives approximately 37.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Rosemary during the growing season.
Lewis County Soil Profile
Soil Type
Silt Loam
Soil pH
5.6-6.2
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 Lewis County
How your county's soil matches Rosemary's growing requirements.
Soil pH
Your soil pH (5.6–6.2) is more acidic than Rosemary prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Lewis County is excellent for Rosemary — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.3%) — Rosemary will thrive.
How to Plant Rosemary
Succession Planting Rosemary
Sow every 9.1 weeks. Last sowing by Apr 27 to harvest before frost.
Plant Water Budget
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 | — | 5.6" | 0" | ❄️ Dormant |
| Feb | — | 3.6" | 0" | ❄️ Dormant |
| Mar | — | 4.1" | 0" | ❄️ Dormant |
| Apr | 1.3" | 2.8" | 0" | ✅ Rainfall sufficient |
| May | 1.3" | 2" | 0" | ✅ Rainfall sufficient |
| Jun | 1.3" | 1.3" | 0" | ✅ Rainfall sufficient |
| Jul | 1.3" | 0.6" | 0.7" | 🚿 Regular watering |
| Aug | 1.3" | 0.6" | 0.7" | 🚿 Regular watering |
| Sep | 1.3" | 1.4" | 0" | ✅ Rainfall sufficient |
| Oct | 1.3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Nov | — | 6.3" | 0" | ❄️ Dormant |
| Dec | — | 5.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Lewis 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 — Lewis County, WA
Rosemary Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | May 2 | May 2 – May 16 |
| Harvest | July 25 | Jul 25 – Dec 12 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Harvest |
| 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: too_acidic
🗺️ USDA Zone
Zone 8a
📆 Growing Season
182 days in Lewis County
Growing Tips for Rosemary in Lewis County
Direct sow Rosemary outdoors after April 25 in Lewis County when soil has warmed and frost danger has passed.
Your 182.0-day growing season in Lewis 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 Lewis County, WA?
Lewis County is in Zone 8a with an average last frost of April 25. Plan your Rosemary planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lewis County, WA?
Lewis County, Washington is in USDA Hardiness Zone 8a. The average last spring frost is April 25 and first fall frost is October 24.
Your Lewis County Garden Planner — Free
A 24-page printable planner built for Lewis County (Zone 8a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.