When to Plant Lemongrass in Contra Costa County, CA
May in Contra Costa County, California — your action list
Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.
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Start harvesting lemongrass
Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.
Looking ahead to June
- First harvests: lemongrass
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.
Contra Costa County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 29, giving you a growing season of approximately 276 days.
At an elevation of 88 feet, Contra Costa County receives approximately 19 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Lemongrass during the growing season. With low rainfall, drip irrigation is essential for growing Lemongrass successfully. Mulch heavily to conserve soil moisture.
Contra Costa County Soil Profile
Soil Type
Loam
Soil pH
6.7-7.8
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 Contra Costa County
How your county's soil matches Lemongrass's growing requirements.
Soil pH
Your soil pH (6.7–7.8) overlaps with Lemongrass's range (5.5–7.5), though not a perfect match.
Soil Texture
The loam soil in Contra Costa County is excellent for Lemongrass — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.0%). Annual compost additions will help Lemongrass.
How to Plant Lemongrass
Succession Planting Lemongrass
Sow every 8.6 weeks. Last sowing by Aug 01 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
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 | — | 4.1" | 0" | ❄️ Dormant |
| Feb | 6.5" | 4.5" | 2" | 💧 Light watering |
| Mar | 6.5" | 3" | 3.5" | 🚿 Regular watering |
| Apr | 6.5" | 1.5" | 5" | 🚿 Regular watering |
| May | 6.5" | 0.6" | 5.9" | 🚿 Regular watering |
| Jun | 6.5" | 0.1" | 6.4" | 🚿 Regular watering |
| Jul | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Aug | 6.5" | 0" | 6.5" | 🚿 Regular watering |
| Sep | 6.5" | 0.2" | 6.3" | 🚿 Regular watering |
| Oct | 6.5" | 0.7" | 5.8" | 🚿 Regular watering |
| Nov | 6.5" | 1.6" | 4.9" | 🚿 Regular watering |
| Dec | — | 2.7" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Contra Costa 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 — Contra Costa County, CA
Lemongrass Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 15 | Jan 15 – Jan 29 |
| Transplant Outdoors | March 5 | Mar 5 – Mar 19 |
| Direct Sow | March 5 | Mar 5 – Mar 26 |
| Harvest | May 21 | May 21 – Aug 20 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | — |
| March | Transplant Outdoors Direct Sow |
| April | — |
| May | Harvest |
| June | Harvest |
| July | Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.5"/week · 2-3 times/week
📅 Days to Maturity
75–120 days
🧪 Soil pH
Needs 5.5–7.5 · Your soil: acceptable
🗺️ USDA Zone
Zone 9b
📆 Growing Season
276 days in Contra Costa County
Growing Tips for Lemongrass in Contra Costa County
Direct sow Lemongrass outdoors after February 26 in Contra Costa 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.
Contra Costa County receives only 19" of rain annually. Lemongrass needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
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 Contra Costa County, CA?
Contra Costa County is in Zone 9b with an average last frost of February 26. Plan your Lemongrass planting based on this frost date — see the calendar above for exact timing.
What planting zone is Contra Costa County, CA?
Contra Costa County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 26 and first fall frost is November 29.
Your Contra Costa County Garden Planner — Free
A 24-page printable planner built for Contra Costa County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.