When to Plant Lemongrass in Polk County, OR
Your May planting checklist for Polk County, Oregon
A quick May briefing for Polk County, Oregon gardeners — what's urgent, what's next, and what can wait.
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Begin indoor sowing: lemongrass
These need a head start before your last frost (April 10). Sow into cells now so you're ready to transplant in a few weeks.
Lemongrass is a tropical grass with a strong citrus aroma used extensively in Southeast Asian cuisine. The swollen stem bases are the most flavorful part.
Polk County, Oregon is in USDA Zone 8b. The average last spring frost is April 10 and the first fall frost is October 31, giving you a growing season of approximately 204 days.
At an elevation of 331 feet, Polk County receives approximately 54.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Lemongrass to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Lemongrass root diseases.
Polk County Soil Profile
Soil Type
Silt Loam
Soil pH
5.7-6.5
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 Polk County
How your county's soil matches Lemongrass's growing requirements.
Soil pH
Your soil pH (5.7–6.5) is within Lemongrass's preferred range (5.5–7.5).
Soil Texture
The silt loam soil in Polk County is excellent for Lemongrass — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (4.7%) — Lemongrass will thrive.
How to Plant Lemongrass
Succession Planting Lemongrass
Sow every 8.6 weeks. Last sowing by Jul 03 to harvest before frost.
Plant Water Budget
Monthly Watering Guide for Lemongrass
Lemongrass needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.
| Month | Lemongrass Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 8.7" | 0" | ❄️ Dormant |
| Feb | — | 5.6" | 0" | ❄️ Dormant |
| Mar | — | 5" | 0" | ❄️ Dormant |
| Apr | 6.5" | 4.2" | 2.3" | 💧 Light watering |
| May | 6.5" | 3.5" | 3" | 💧 Light watering |
| Jun | 6.5" | 2.4" | 4.1" | 🚿 Regular watering |
| Jul | 6.5" | 0.9" | 5.6" | 🚿 Regular watering |
| Aug | 6.5" | 1.1" | 5.4" | 🚿 Regular watering |
| Sep | 6.5" | 1.8" | 4.7" | 🚿 Regular watering |
| Oct | 6.5" | 4.5" | 2" | 💧 Light watering |
| Nov | — | 8.1" | 0" | ❄️ Dormant |
| Dec | — | 8.8" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Polk County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Lemongrass 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.
Lemongrass Planting Timeline — Polk County, OR
Lemongrass Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 20 | Feb 20 – Mar 6 |
| Transplant Outdoors | April 24 | Apr 24 – May 8 |
| Direct Sow | April 17 | Apr 17 – May 8 |
| Harvest | July 10 | Jul 10 – Oct 9 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | Start Indoors |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · 1-2 times/week
📅 Days to Maturity
75–120 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 8b
📆 Growing Season
204 days in Polk County
Growing Tips for Lemongrass in Polk County
Direct sow Lemongrass outdoors after April 10 in Polk County when soil has warmed and frost danger has passed.
Common pests for Lemongrass in this region include corn earworm and corn borers. Use row covers early in the season and inspect plants weekly.
General growing tips
Start from divisions or store-bought stalks rooted in water. Grow in rich, moist soil with full sun. In cold climates, grow in containers and overwinter indoors.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Lemongrass in Other Locations
Frequently Asked Questions
When should I plant Lemongrass in Polk County, OR?
Polk County is in Zone 8b with an average last frost of April 10. Plan your Lemongrass planting based on this frost date — see the calendar above for exact timing.
What planting zone is Polk County, OR?
Polk County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 10 and first fall frost is October 31.
Your Polk County Garden Planner — Free
A 24-page printable planner built for Polk County (Zone 8b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.