When to Plant Basil in Lewis County, WA
What to do 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.
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Move basil from tray to bed
Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.
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Scatter basil into prepared beds
Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.
Coming up in June — start thinking about
- Starting indoors: basil
Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.
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 Basil 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 Basil's growing requirements.
Soil pH
Your soil pH (5.6–6.2) is more acidic than Basil prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Lewis County is excellent for Basil — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (5.3%) — Basil will thrive.
How to Plant Basil
Succession Planting Basil
Sow every 5.7 weeks. Last sowing by Aug 10 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Basil
Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.
| Month | Basil Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 5.6" | 0" | ❄️ Dormant |
| Feb | — | 3.6" | 0" | ❄️ Dormant |
| Mar | — | 4.1" | 0" | ❄️ Dormant |
| Apr | 2.6" | 2.8" | 0" | ✅ Rainfall sufficient |
| May | 2.6" | 2" | 0.6" | 💧 Light watering |
| Jun | 2.6" | 1.3" | 1.3" | 🚿 Regular watering |
| Jul | 2.6" | 0.6" | 2" | 🚿 Regular watering |
| Aug | 2.6" | 0.6" | 2" | 🚿 Regular watering |
| Sep | 2.6" | 1.4" | 1.2" | 💧 Light watering |
| Oct | 2.6" | 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.
Basil 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.
Basil Planting Timeline — Lewis County, WA
Basil Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 7 | Mar 7 – Mar 21 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Direct Sow | May 2 | May 2 – May 23 |
| Harvest | July 4 | Jul 4 – Sep 5 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.6"/week · Natural rainfall sufficient
📅 Days to Maturity
50–75 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 8a
📆 Growing Season
182 days in Lewis County
Growing Tips for Basil in Lewis County
Direct sow Basil outdoors after April 25 in Lewis County when soil has warmed and frost danger has passed.
General growing tips
Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 150 ft between varieties. Different basil species can cross.
Basil in Other Locations
Frequently Asked Questions
When should I plant Basil in Lewis County, WA?
Lewis County is in Zone 8a with an average last frost of April 25. Plan your Basil 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.