When to Plant Komatsuna in Lake County, CA
May in Lake County, California — your action list
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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Start harvesting komatsuna
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Komatsuna (Japanese mustard spinach) is a versatile Asian green with glossy, dark leaves and a mild, sweet flavor. It is extremely cold-hardy and heat-tolerant.
Lake County, California is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 27, giving you a growing season of approximately 270 days.
At an elevation of 154 feet, Lake County receives approximately 30.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 83°F, so choose short-season varieties of Komatsuna to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Komatsuna will need more frequent watering and organic matter to retain nutrients.
Lake County Soil Profile
Soil Type
Sandy Loam
Soil pH
6.1-6.9
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.
Soil Compatibility in Lake County
How your county's soil matches Komatsuna's growing requirements.
Soil pH
Your soil pH (6.1–6.9) is within Komatsuna's preferred range (6.0–7.5).
Soil Texture
Sandy soil in Lake County warms quickly in spring but drains fast. Komatsuna will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is moderate (2.7%). Annual compost additions will help Komatsuna.
How to Plant Komatsuna
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Komatsuna
Sow every 4 weeks. Last sowing by Oct 08 to harvest before frost.
For a dedicated fall crop, sow by Oct 02.
Plant Water Budget
Monthly Watering Guide for Komatsuna
Komatsuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Komatsuna Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 6.2" | 0" | ❄️ Dormant |
| Feb | — | 6.5" | 0" | ❄️ Dormant |
| Mar | 4.3" | 4.6" | 0" | ✅ Rainfall sufficient |
| Apr | 4.3" | 2.7" | 1.6" | 💧 Light watering |
| May | 4.3" | 0.8" | 3.5" | 🚿 Regular watering |
| Jun | 4.3" | 0.2" | 4.1" | 🚿 Regular watering |
| Jul | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Aug | 4.3" | 0" | 4.3" | 🚿 Regular watering |
| Sep | 4.3" | 0.3" | 4" | 🚿 Regular watering |
| Oct | 4.3" | 1.1" | 3.2" | 🚿 Regular watering |
| Nov | 4.3" | 3" | 1.3" | 💧 Light watering |
| Dec | — | 5.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Lake County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Komatsuna 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.
Komatsuna Planting Timeline — Lake County, CA
Komatsuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 2 | Feb 2 – Feb 16 |
| Transplant Outdoors | March 2 | Mar 2 – Mar 16 |
| Direct Sow | February 9 | Feb 9 – Mar 2 |
| Harvest | April 6 | Apr 6 – May 11 |
| Fall Sowing | October 2 | Oct 2 – Oct 16 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors Direct Sow |
| March | Transplant Outdoors Direct Sow |
| April | Harvest |
| May | Harvest |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 1-2 times/week
📅 Days to Maturity
35–50 days
🧪 Soil pH
Needs 6–7.5 · Your soil: ideal
🗺️ USDA Zone
Zone 9a
📆 Growing Season
270 days in Lake County
Growing Tips for Komatsuna in Lake County
Direct sow Komatsuna outdoors after March 02 in Lake County when soil has warmed and frost danger has passed.
Sandy soil in Lake County dries quickly — mulch Komatsuna with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
Your generous 270.0-day season in Lake County allows multiple plantings of Komatsuna. Sow every 17.0 days for continuous harvest.
Common pests for Komatsuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in spring or fall. One of the most forgiving Asian greens for all seasons. Harvest outer leaves or cut whole plants. Excellent for stir-fries, soups, or salads.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Komatsuna in Other Locations
Frequently Asked Questions
When should I plant Komatsuna in Lake County, CA?
Lake County is in Zone 9a with an average last frost of March 2. Plan your Komatsuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Lake County, CA?
Lake County, California is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 27.
Your Lake County Garden Planner — Free
A 24-page printable planner built for Lake County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.