When to Plant Mustard Greens in Marin County, CA
Mustard greens are fast-growing brassicas with a spicy, peppery kick. They come in green, red, and purple varieties and are excellent cooked or in salads.
Marin County, California is in USDA Zone 10a. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.
At an elevation of 302 feet, Marin County receives approximately 36 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 81°F, so choose short-season varieties of Mustard Greens to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Mustard Greens will need more frequent watering and organic matter to retain nutrients.
Marin County Soil Profile
Soil Type
Sandy Loam
Soil pH
6-6.9
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.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Mustard Greens Planting Timeline — Marin County, CA
Mustard Greens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 29 | Jan 29 – Feb 12 |
| Transplant Outdoors | February 26 | Feb 26 – Mar 12 |
| Direct Sow | February 5 | Feb 5 – Feb 26 |
| Fall Sowing | October 1 | Oct 1 – Oct 15 |
| Harvest | April 2 | Apr 2 – Jun 4 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Transplant Outdoors |
| April | Harvest |
| May | Harvest |
| June | Harvest |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
Sun
Partial Shade (3-6 hours)
Water
Moderate — regular watering
Days to Maturity
30–50 days
Soil pH
6 – 7
USDA Zone
Zone 10a
Growing Season
273 days
Growing Tips for Marin County
Direct sow in early spring or fall. Harvest young leaves for milder flavor. Plants bolt quickly in heat so grow as a cool-season crop or provide shade.
Companion Planting
Good Companions
Avoid Planting Near
Level Up Your Garden
Mustard Greens in Other Locations
Frequently Asked Questions
When should I plant Mustard Greens in Marin County, CA?
Marin County is in Zone 10a with an average last frost of February 26. Plan your Mustard Greens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Marin County, CA?
Marin County, California is in USDA Hardiness Zone 10a. The average last spring frost is February 26 and first fall frost is November 26.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Marin County gardeners in Zone 10a organize planting dates, track what's growing, and never miss a planting window.
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