When to Plant Mint in San Mateo County, CA
May to-do list for San Mateo County, California
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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Collect mint at their peak
If you can't use it all right away, check the food-preservation section of your planner.
Before June arrives, get these ready
- First harvests: mint
Mint is a vigorous perennial herb with refreshing, aromatic leaves used in teas, cocktails, and cooking. It spreads aggressively by underground runners.
San Mateo County, California is in USDA Zone 10a. The average last spring frost is January 18 and the first fall frost is December 12, giving you a growing season of approximately 328 days.
At an elevation of 277 feet, San Mateo County receives approximately 16.9 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Mint to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Mint successfully. Mulch heavily to conserve soil moisture.
San Mateo County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.2
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 San Mateo County
How your county's soil matches Mint's growing requirements.
Soil pH
Your soil pH (6.8–7.2) overlaps with Mint's range (6.0–7.0), though not a perfect match.
Soil Texture
The loam soil in San Mateo County is excellent for Mint — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Mint is a heavy drinker but your soil drains very quickly. Mulch heavily and consider drip irrigation.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Mint.
How to Plant Mint
Succession Planting Mint
Sow every 6.9 weeks. Last sowing by Sep 13 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Mint
Mint needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.
| Month | Mint Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | 3" | 3.9" | 0" | ✅ Rainfall sufficient |
| Feb | 3" | 3.4" | 0" | ✅ Rainfall sufficient |
| Mar | 3" | 2.7" | 0.3" | 💧 Light watering |
| Apr | 3" | 1.2" | 1.8" | 🚿 Regular watering |
| May | 3" | 0.4" | 2.6" | 🚿 Regular watering |
| Jun | 3" | 0.1" | 2.9" | 🚿 Regular watering |
| Jul | 3" | 0" | 3" | 🚿 Regular watering |
| Aug | 3" | 0" | 3" | 🚿 Regular watering |
| Sep | 3" | 0.2" | 2.8" | 🚿 Regular watering |
| Oct | 3" | 0.7" | 2.3" | 🚿 Regular watering |
| Nov | 3" | 1.4" | 1.6" | 🚿 Regular watering |
| Dec | 3" | 2.9" | 0.1" | 💧 Light watering |
Water needs are for active growing months only (Jan–Dec in San Mateo County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Mint 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.
Mint Planting Timeline — San Mateo County, CA
Mint Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | January 25 | Jan 25 – Feb 8 |
| Harvest | March 29 | Mar 29 – Jun 7 |
Plant 0.5" deep · 8" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Transplant Outdoors |
| February | Transplant Outdoors |
| March | Harvest |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
0.7"/week · 2-3 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: acceptable
🗺️ USDA Zone
Zone 10a
📆 Growing Season
328 days in San Mateo County
Growing Tips for Mint in San Mateo County
Direct sow Mint outdoors after January 18 in San Mateo County when soil has warmed and frost danger has passed.
General growing tips
Always grow mint in containers or with underground barriers to control spreading. Harvest regularly to keep plants compact. Cut plants back in late summer for a fresh fall flush.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Mint in Other Locations
Frequently Asked Questions
When should I plant Mint in San Mateo County, CA?
San Mateo County is in Zone 10a with an average last frost of January 18. Plan your Mint planting based on this frost date — see the calendar above for exact timing.
What planting zone is San Mateo County, CA?
San Mateo County, California is in USDA Hardiness Zone 10a. The average last spring frost is January 18 and first fall frost is December 12.
Your San Mateo County Garden Planner — Free
A 24-page printable planner built for San Mateo County (Zone 10a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.