When to plant Escarole in Boulder County, CO
Spring Escarole in Boulder County goes in April 30–May 21, once nighttime temps stop dipping near freezing. A second sowing from July 18 to August 1 extends the harvest into fall.
When to Plant Escarole in Boulder County, CO
Top priorities for Boulder County, Colorado gardeners in June
Your Boulder County, Colorado garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.
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Begin indoor sowing: escarole
You're about 14 weeks out from your last frost — the perfect window to get these germinating indoors.
A few tasks this June that'll pay off in July
- First harvests: escarole
- Fall sowing: escarole
Escarole is a broad-leaved endive with slightly bitter, sturdy leaves. The outer leaves are more bitter while the blanched heart is tender and mild.
Boulder County, Colorado is in USDA Zone 6a. 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 7,657 feet, Boulder County receives approximately 22.2 inches of rainfall annually with predominantly loam soil. Summer highs average 86°F, providing good warmth for Escarole during the growing season.
Boulder County Soil Profile
Soil Type
Loam
Soil pH
6.7-8
Drainage
Well Drained
Escarole 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 Boulder County
How your county's soil matches Escarole's growing requirements.
Soil pH
Your soil pH (6.7–8.0) is more alkaline than Escarole prefers (5.5–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Boulder County is excellent for Escarole — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Escarole.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Escarole.
How to Plant Escarole
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Escarole
Sow every 5.7 weeks. Last sowing by Jul 18 to harvest before frost.
For a dedicated fall crop, sow by Jul 18.
Escarole Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Escarole
Escarole needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Escarole Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | 4.3" | 3" | 1.3" | 💧 Light watering |
| Jun | 4.3" | 1.6" | 2.7" | 🚿 Regular watering |
| Jul | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Aug | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Sep | 4.3" | 2.1" | 2.2" | 🚿 Regular watering |
| Oct | — | 1.9" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Boulder County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Escarole 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.
Escarole Planting Timeline — Boulder County, CO
Escarole 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 | July 9 | Jul 9 – Aug 6 |
| Fall Sowing | July 18 | Jul 18 – Aug 1 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing Harvest |
| August | Fall Sowing Harvest |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
50–70 days
🧪 Soil pH
Needs 5.5–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 6a
📆 Growing Season
135 days in Boulder County
Growing Tips for Escarole in Boulder County
Direct sow Escarole outdoors after May 14 in Boulder County when soil has warmed and frost danger has passed.
Common pests for Escarole in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.
Boulder County receives only 22" of rain annually. Escarole needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Direct sow in spring or late summer. Blanch heads by tying outer leaves together or covering with a pot for 2 weeks before harvest. Excellent braised or in soups.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Escarole in Other Locations
Frequently Asked Questions
When should I plant Escarole in Boulder County, CO?
Boulder County is in Zone 6a with an average last frost of May 14. Plan your Escarole planting based on this frost date — see the calendar above for exact timing.
What planting zone is Boulder County, CO?
Boulder County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 14 and first fall frost is September 26.
When should I plant Escarole in Boulder County, CO?
In Boulder County, CO, plant Escarole after the last frost (around May 14) and before the first frost (around September 26). Best results when soil holds above 50°F.
What growing zone is Boulder County, CO for Escarole?
Boulder County sits in USDA Zone 6a. Escarole grows reliably in zones 3a through 10b, so it's a good fit here.
Can Escarole grow in Boulder County's climate?
Yes — Escarole grows well in Boulder County's temperate climate. Boulder County averages a 135-day frost-free season, with last frost around May 14 and first frost around September 26.
Your Boulder County Garden Planner — Free
A 22-page printable planner built for Boulder 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.