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When to Plant Eggplant in Salt Lake County, UT

Salt Lake County, Utah Zone 7b May

May in Salt Lake County, Utah — your action list

Your Salt Lake County, Utah garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 6
Avg. first frost October 10
Soil temp (4") 49°F
Watering High
Pest pressure Low
Daylight 14.3 hrs
  1. Harden off and plant eggplant

    Pinch off the lowest leaves on each seedling before you plant — it reduces water loss while the roots catch up.

  2. Sow eggplant where they'll grow

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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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.

Salt Lake County, Utah is in USDA Zone 7b. The average last spring frost is May 6 and the first fall frost is October 10, giving you a growing season of approximately 157 days.

At an elevation of 4,960 feet, Salt Lake County receives approximately 12.2 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Eggplant during the growing season. With low rainfall, drip irrigation is essential for growing Eggplant successfully. Mulch heavily to conserve soil moisture.

Salt Lake County, UT (Zone 7b) Moderate season
157 days
Last Spring Frost May 6
157 growing days
First Fall Frost October 10

Salt Lake County Soil Profile

Soil Type

Loam

Soil pH

6.7-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (9 days to spare)
Start indoors: Feb 22 Transplant: May 10 🍅 Harvest: Jul 19 – Sep 20
Recommended (50%) ✓ Fits season (10 days to spare)
Start indoors: Mar 4 Transplant: May 20 🍅 Harvest: Jul 29 – Sep 30
Safe Start (90%) ✗ May not fit
Start indoors: Apr 8 Transplant: Jun 24 🍅 Harvest: Sep 2 – Nov 4

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 Salt Lake County

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

Soil pH

Your soil pH (6.7–8.3) is more alkaline than Eggplant prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.6%). Annual compost additions will help Eggplant.

How to Plant Eggplant

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

Succession Planting Eggplant

2
successive plantings in your 157-day season

Sow every 7.4 weeks. Last sowing by Jul 17 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.3″/week
You supply
0.9″/week
Watering frequency 2-3 times/week
Season total 1,297 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 0.9" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.8" 1.4" 3.4" 🚿 Regular watering
Jun 4.8" 1" 3.8" 🚿 Regular watering
Jul 4.8" 1.1" 3.7" 🚿 Regular watering
Aug 4.8" 1.4" 3.4" 🚿 Regular watering
Sep 4.8" 0.9" 3.9" 🚿 Regular watering
Oct 4.8" 1.2" 3.6" 🚿 Regular watering
Nov 0.8" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Salt Lake 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 ~1,200 GDD — county provides 2,512 GDD Excellent fit

Eggplant Planting Timeline — Salt Lake County, UT

Eggplant Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors May 20 May 20 – Jun 3
Direct Sow May 13 May 13 – Jun 3
Harvest July 29 Jul 29 – Sep 30

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 2-3 times/week

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 7b

📆 Growing Season

157 days in Salt Lake County

Growing Tips for Eggplant in Salt Lake County

Direct sow Eggplant outdoors after May 06 in Salt Lake County when soil has warmed and frost danger has passed.

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

Salt Lake County receives only 12" 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 Salt Lake County, UT?

Salt Lake County is in Zone 7b with an average last frost of May 6. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Salt Lake County, UT?

Salt Lake County, Utah is in USDA Hardiness Zone 7b. The average last spring frost is May 6 and first fall frost is October 10.

🌱

Your Salt Lake County Garden Planner — Free

A 24-page printable planner built for Salt Lake County (Zone 7b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Salt Lake County, UT. 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.