When to Plant Leeks in Gilpin County, CO
This month in Gilpin County, Colorado
May rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Gilpin County, Colorado.
-
Harden off and plant leeks
Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.
June prep starts now
- 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.
Gilpin County, Colorado is in USDA Zone 5b. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.
At an elevation of 6,444 feet, Gilpin County receives approximately 18.6 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Leeks to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Leeks successfully. Mulch heavily to conserve soil moisture.
Gilpin County Soil Profile
Soil Type
Loam
Soil pH
6.8-8
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 Gilpin County
How your county's soil matches Leeks's growing requirements.
Soil pH
Your soil pH (6.8–8.0) is more alkaline than Leeks prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Gilpin County is excellent for Leeks — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Leeks.
How to Plant Leeks
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant 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 | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | — | 2.1" | 0" | ❄️ Dormant |
| May | 3.5" | 1.8" | 1.7" | 💧 Light watering |
| Jun | 3.5" | 1.4" | 2.1" | 🚿 Regular watering |
| Jul | 3.5" | 1.7" | 1.8" | 🚿 Regular watering |
| Aug | 3.5" | 2.1" | 1.4" | 💧 Light watering |
| Sep | 3.5" | 1.3" | 2.2" | 🚿 Regular watering |
| Oct | — | 1.7" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Gilpin 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 — Gilpin County, CO
Leeks Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 9 | Apr 9 – Apr 23 |
| Transplant Outdoors | May 14 | May 14 – May 28 |
| Direct Sow | April 30 | Apr 30 – May 21 |
| Harvest | August 13 | Aug 13 – Oct 29 |
| Fall Sowing | July 18 | Jul 18 – Aug 1 |
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 5b
📆 Growing Season
135 days in Gilpin County
Growing Tips for Leeks in Gilpin County
Direct sow Leeks outdoors after May 14 in Gilpin County when soil has warmed and frost danger has passed.
Your 135.0-day growing season in Gilpin 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
Frequently Asked Questions
When should I plant Leeks in Gilpin County, CO?
Gilpin County is in Zone 5b with an average last frost of May 14. Plan your Leeks planting based on this frost date — see the calendar above for exact timing.
What planting zone is Gilpin County, CO?
Gilpin County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 14 and first fall frost is September 26.
Your Gilpin County Garden Planner — Free
A 24-page printable planner built for Gilpin County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.