When to plant Leeks in Jackson County County,
For Leeks in Jackson County County, the safe spring window opens around June 6 and closes around June 27. Last expected frost is June 13, first fall frost September 4, giving a 83-day growing season. A second sowing from June 12 to June 26 extends the harvest into fall.
When to Plant Leeks in Jackson County, CO
June in the garden — Jackson County, Colorado
June is a pivotal month for Jackson County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Move leeks from tray to bed
Your last frost (June 13) has passed. These warm-season crops can handle outdoor soil now.
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Outdoor sowing time: leeks
These tolerate cool soil, so you're not gambling by sowing now.
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Kick off the fall garden with leeks
Count back from your first frost (September 4) — these need to mature before the cold arrives.
A few tasks this June that'll pay off in July
- Starting indoors: leeks
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.
Jackson County, Colorado is in USDA Zone 4b. The average last spring frost is June 13 and the first fall frost is September 4, giving you a growing season of approximately 83 days.
At an elevation of 5,388 feet, Jackson County receives approximately 20.9 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Leeks to ensure they mature before fall.
Jackson County Soil Profile
Soil Type
Loam
Soil pH
6.6-8.1
Drainage
Well Drained
Leeks 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 Jackson County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.6–8.1) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Jackson County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Leeks.
How to Plant Leeks
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Leeks Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Leeks
Leeks needs approximately 0.8 inches of water per week (3.5" per month). Here's how your county's rainfall compares month by month.
| Month | Leeks Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.1" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 2.3" | 0" | ❄️ Dormant |
| May | — | 2.2" | 0" | ❄️ Dormant |
| Jun | 3.5" | 1.7" | 1.8" | 🚿 Regular watering |
| Jul | 3.5" | 1.7" | 1.8" | 🚿 Regular watering |
| Aug | 3.5" | 2.5" | 1" | 💧 Light watering |
| Sep | 3.5" | 1.5" | 2" | 🚿 Regular watering |
| Oct | — | 2.1" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Jun–Sep in Jackson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Leeks 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.
Leeks Planting Timeline — Jackson County, CO
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | May 2 | May 2 – May 16 |
| Transplant Outdoors | June 13 | Jun 13 – Jun 27 |
| Direct Sow | June 6 | Jun 6 – Jun 27 |
| Harvest | September 12 | Sep 12 – Nov 7 |
| Fall Sowing | June 12 | Jun 12 – Jun 26 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Start Indoors |
| June | Transplant Outdoors Direct Sow Fall Sowing |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | Harvest |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Natural rainfall sufficient
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 4b
📆 Growing Season
83 days in Jackson County
Growing Tips for Leeks in Jackson County
Direct sow Leeks outdoors after June 13 in Jackson County when soil has warmed and frost danger has passed.
Your 83.0-day growing season in Jackson County is tight for Leeks (90.0-150.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Leeks in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.
General growing tips
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
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Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
Frequently Asked Questions
When should I plant Leeks in Jackson County, CO?
Jackson County is in Zone 4b with an average last frost of June 13. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jackson County, CO?
Jackson County, Colorado is in USDA Hardiness Zone 4b. The average last spring frost is June 13 and first fall frost is September 4.
When should I plant Leeks in Jackson County, ?
In Jackson County, , plant Leeks after the last frost (around June 13) and before the first frost (around September 4). Best results when soil holds above 50°F.
What growing zone is Jackson County, for Leeks?
Jackson County sits in USDA Zone 4b. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.
Can Leeks grow in Jackson County's climate?
Yes — Leeks grows well in Jackson County's temperate climate. Jackson County averages a 83-day frost-free season, with last frost around June 13 and first frost around September 4.
Your Jackson County Garden Planner — Free
A 22-page printable planner built for Jackson County (Zone 4b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.