When to plant Leeks in Cascade, CO
Plant Leeks in Cascade from April 27 to May 18 in spring. Cascade sits in USDA Zone 6a, with last frost around May 11 and first frost on October 6. A second sowing from July 28 to August 11 extends the harvest into fall.
When to Plant Leeks in Cascade, CO
El Paso County, Colorado gardeners: here's your June plan
Your garden in El Paso County, Colorado is working on a schedule, even when you're not. Here's where you should be this June.
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Start leeks under lights
Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.
A few tasks this June that'll pay off in July
- Fall sowing: 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.
Cascade, Colorado is in USDA Zone 6a. The average last spring frost is May 11 and the first fall frost is October 6, giving you a growing season of approximately 148 days.
At an elevation of 8,317 feet, El Paso County receives approximately 23.5 inches of rainfall annually with predominantly loam soil. Summer highs average 87°F, providing good warmth for Leeks during the growing season.
Cascade Soil Profile
Soil Type
Loam
Soil pH
6.5-7.9
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 Cascade
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.5–7.9) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in El Paso County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.4%). Annual compost additions will help Leeks.
How to Plant Leeks
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Leeks Water Budget
Water stress score is 8/10 — 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 | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.6" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | — | 2.4" | 0" | ❄️ Dormant |
| May | 3.5" | 2.8" | 0.7" | 💧 Light watering |
| Jun | 3.5" | 1.6" | 1.9" | 🚿 Regular watering |
| Jul | 3.5" | 2.3" | 1.2" | 💧 Light watering |
| Aug | 3.5" | 3" | 0.5" | 💧 Light watering |
| Sep | 3.5" | 1.7" | 1.8" | 🚿 Regular watering |
| Oct | 3.5" | 1.9" | 1.6" | 💧 Light watering |
| Nov | — | 1.5" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in El Paso 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 — Cascade, CO
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 6 | Apr 6 – Apr 20 |
| Transplant Outdoors | May 11 | May 11 – May 25 |
| Direct Sow | April 27 | Apr 27 – May 18 |
| Harvest | August 10 | Aug 10 – Oct 26 |
| Fall Sowing | July 28 | Jul 28 – Aug 11 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing |
| August | Fall Sowing Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.8"/week · Only during dry spells
📅 Days to Maturity
90–150 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 6a
📆 Growing Season
148 days in El Paso County
Growing Tips for Leeks in Cascade
Direct sow Leeks outdoors after May 11 in El Paso County when soil has warmed and frost danger has passed.
Your 148.0-day growing season in El Paso 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
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Leeks in Other Locations
When should I plant Leeks in Cascade, CO?
In Cascade, CO, plant Leeks after the last frost (around May 11) and before the first frost (around October 6). Best results when soil holds above 50°F.
What growing zone is Cascade, CO for Leeks?
Cascade sits in USDA Zone 6a. Leeks grows reliably in zones 3a through 10b, so it's a good fit here.
Can Leeks grow in Cascade's climate?
Yes — Leeks grows well in Cascade's temperate climate. Cascade averages a 148-day frost-free season, with last frost around May 11 and first frost around October 6.
Your El Paso County Garden Planner — Free
A 22-page printable planner built for El Paso County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.