When to plant Mizuna in Summit County, CO
Summit County gardeners should plant Mizuna between June 2 and June 23 in spring. With Summit County's Zone 5a climate (last frost June 16), Mizuna needs 30–45 days to mature — plant by July 21 for a full harvest. A second sowing from June 26 to July 10 extends the harvest into fall.
When to Plant Mizuna in Summit County, CO
Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.
Summit County, Colorado is in USDA Zone 5a. The average last spring frost is June 16 and the first fall frost is September 4, giving you a growing season of approximately 80 days.
At an elevation of 7,005 feet, Summit County receives approximately 17.5 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Mizuna to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Mizuna successfully. Mulch heavily to conserve soil moisture.
Summit County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Mizuna Planting Timeline — Summit County, CO
Mizuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 12 | May 12 – May 26 |
| Transplant Outdoors | June 16 | Jun 16 – Jun 30 |
| Direct Sow | June 2 | Jun 2 – Jun 23 |
| Harvest | July 21 | Jul 21 – Aug 18 |
| Fall Sowing | June 26 | Jun 26 – Jul 10 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | Fall Sowing Harvest |
| August | Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
30–45 days
🧪 Soil pH
Needs 6–7.5 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
80 days in Summit County
Growing Tips for Summit County
Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Mizuna in Other Locations
Frequently Asked Questions
When should I plant Mizuna in Summit County, CO?
Summit County is in Zone 5a with an average last frost of June 16. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Summit County, CO?
Summit County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 16 and first fall frost is September 4.
When should I plant Mizuna in Summit County, CO?
In Summit County, CO, plant Mizuna after the last frost (around June 16) and before the first frost (around September 4). Best results when soil holds above 50°F.
What growing zone is Summit County, CO for Mizuna?
Summit County sits in USDA Zone 5a. Mizuna grows reliably in zones 3a through 11b, so it's a good fit here.
Can Mizuna grow in Summit County's climate?
Yes — Mizuna grows well in Summit County's temperate climate. Summit County averages a 80-day frost-free season, with last frost around June 16 and first frost around September 4.
Your Summit County Garden Planner — Free
A 22-page printable planner built for Summit County (Zone 5a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.