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When to Plant Eggplant in Routt County, CO

Routt County, Colorado Zone 5a May

What to do in May

May is a pivotal month for Routt County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost June 12
Avg. first frost September 8
Soil temp (4") 39°F
Watering Moderate
Pest pressure Low
Daylight 14.2 hrs
To set up a strong June, finish these tasks
  • Transplants going out: eggplant
  • Direct-sowing: eggplant

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Eggplant is a heat-loving solanaceous crop that produces glossy fruits in purple, white, or striped varieties. It requires long, warm growing seasons for best production.

Routt County, Colorado is in USDA Zone 5a. The average last spring frost is June 12 and the first fall frost is September 8, giving you a growing season of approximately 88 days.

At an elevation of 5,381 feet, Routt County receives approximately 24.5 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Eggplant to ensure they mature before fall.

Routt County, CO (Zone 5a) Very short season
88 days
Last Spring Frost June 12
88 growing days
First Fall Frost September 8

Routt County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 24 Transplant: Jun 16 🍅 Harvest: Aug 25 – Oct 27
Recommended (50%) ✗ May not fit
Start indoors: Apr 3 Transplant: Jun 26 🍅 Harvest: Sep 4 – Nov 6
Safe Start (90%) ✗ May not fit
Start indoors: Apr 16 Transplant: Jul 9 🍅 Harvest: Sep 17 – Nov 19

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 Routt County

How your county's soil matches Eggplant's growing requirements.

Soil pH

Your soil pH (6.7–7.9) is more alkaline than Eggplant prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Routt County is excellent for Eggplant — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Eggplant.

How to Plant Eggplant

1"
Planting Depth
30"
Between Plants
42"
Between Rows

How Much Eggplant to Grow

4-6 lbs
Average yield per plant
2
Plants per person
17.5 sq ft
Space per person

For a family of 4, plant approximately 8 eggplant plants in about 70 sq ft. In Routt County's 88-day season, you'll have plenty of time for a full harvest. Plan your garden layout →

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
1.2″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Eggplant

Eggplant needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Eggplant Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 2.7" 0" ❄️ Dormant
May 2.8" 0" ❄️ Dormant
Jun 4.8" 1.5" 3.3" 🚿 Regular watering
Jul 4.8" 2.2" 2.6" 🚿 Regular watering
Aug 4.8" 2.2" 2.6" 🚿 Regular watering
Sep 4.8" 2.3" 2.5" 🚿 Regular watering
Oct 1.9" 0" ❄️ Dormant
Nov 1.5" 0" ❄️ Dormant
Dec 1.5" 0" ❄️ Dormant

Water needs are for active growing months only (Jun–Sep in Routt County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Eggplant 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.

Eggplant needs ~919 GDD — county provides 1,078 GDD Good fit

Eggplant Planting Timeline — Routt County, CO

Eggplant Planting Calendar

Activity When Date Range
Start Indoors April 3 Apr 3 – Apr 17
Transplant Outdoors June 26 Jun 26 – Jul 10
Direct Sow June 19 Jun 19 – Jul 10
Harvest September 4 Sep 4 – Nov 6

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May
June Transplant Outdoors Direct Sow
July Transplant Outdoors Direct Sow
August
September Harvest
October Harvest
November Harvest
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Natural rainfall sufficient

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

88 days in Routt County

Growing Tips for Eggplant in Routt County

Direct sow Eggplant outdoors after June 12 in Routt County when soil has warmed and frost danger has passed.

Your 88.0-day growing season in Routt County is tight for Eggplant (65.0-85.0 days to maturity). Start indoors and choose early-maturing varieties.

Common pests for Eggplant in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.

Routt County receives only 24" of rain annually. Eggplant needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 8-10 weeks before last frost. Transplant only after nighttime temperatures stay above 55F. Mulch to retain moisture and warmth around roots.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel
  • Kohlrabi

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Eggplant in Routt County, CO?

Routt County is in Zone 5a with an average last frost of June 12. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Routt County, CO?

Routt County, Colorado is in USDA Hardiness Zone 5a. The average last spring frost is June 12 and first fall frost is September 8.

🌱

Your Routt County Garden Planner — Free

A 24-page printable planner built for Routt 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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Routt County, CO. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.