When to plant Leeks in Grand County, CO
Plant Leeks in Grand County from May 14 to June 4 in spring. Grand County sits in USDA Zone 5a, with last frost around May 28 and first frost on September 19. A second sowing from July 11 to July 25 extends the harvest into fall.
When to Plant Leeks in Grand County, CO
Leeks are a mild, sweet allium that produces long white shanks. They are more refined than onions and are a key ingredient in soups, stews, and gratins.
Grand County, Colorado is in USDA Zone 5a. The average last spring frost is May 28 and the first fall frost is September 19, giving you a growing season of approximately 114 days.
At an elevation of 5,397 feet, Grand County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 82°F, so choose short-season varieties of Leeks to ensure they mature before fall.
Grand County Soil Profile
Soil Type
Loam
Soil pH
6.0-7.0
Drainage
Well Drained
Leeks Planting Timeline — Grand County, CO
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 23 | Apr 23 – May 7 |
| Transplant Outdoors | May 28 | May 28 – Jun 11 |
| Direct Sow | May 14 | May 14 – Jun 4 |
| Harvest | August 27 | Aug 27 – Nov 12 |
| Fall Sowing | July 11 | Jul 11 – Jul 25 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Start Indoors Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
Moderate — regular watering
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: N/A
🗺️ USDA Zone
Zone 5a
📆 Growing Season
114 days in Grand County
Growing Tips for Grand County
Start seeds indoors 10-12 weeks before last frost. Transplant into trenches and hill soil around stems as they grow to increase the white portion. Harvest as needed.
Companion Planting
Good Companions
Avoid Planting Near
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Leeks in Other Locations
Frequently Asked Questions
When should I plant Leeks in Grand County, CO?
Grand County is in Zone 5a with an average last frost of May 28. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Grand County, CO?
Grand County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is May 28 and first fall frost is September 19.
When should I plant Leeks in Grand County, CO?
In Grand County, CO, plant Leeks after the last frost (around May 28) and before the first frost (around September 19). Best results when soil holds above 50°F.
What growing zone is Grand County, CO for Leeks?
Grand County sits in USDA Zone 5a. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.
Can Leeks grow in Grand County's climate?
Yes — Leeks grows well in Grand County's temperate climate. Grand County averages a 114-day frost-free season, with last frost around May 28 and first frost around September 19.
Your Grand County Garden Planner — Free
A 22-page printable planner built for Grand 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.