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When to Plant Eggplant in Putnam County, MO

Putnam County, Missouri Zone 5b May

What to do in May

We've pulled the most time-sensitive tasks for Putnam County, Missouri this May and put them front and centre. Tackle them in order.

Avg. last frost April 18
Avg. first frost October 16
Soil temp (4") 58°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Harden off and plant eggplant

    Frost risk is low now in Putnam County, Missouri. If you've been covering beds overnight, you can stop.

Looking ahead to June
  • Starting indoors: 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.

Putnam County, Missouri is in USDA Zone 5b. The average last spring frost is April 18 and the first fall frost is October 16, giving you a growing season of approximately 181 days.

At an elevation of 1,185 feet, Putnam County receives approximately 40.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Eggplant to ensure they mature before fall.

Putnam County, MO (Zone 5b) Moderate season
181 days
Last Spring Frost April 18
181 growing days
First Fall Frost October 16
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Putnam County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (34 days to spare)
Start indoors: Feb 2 Transplant: Apr 27 🍅 Harvest: Jul 6 – Sep 7
Recommended (50%) ✓ Fits season (34 days to spare)
Start indoors: Feb 7 Transplant: May 2 🍅 Harvest: Jul 11 – Sep 12
Safe Start (90%) ✓ Fits season (34 days to spare)
Start indoors: Feb 22 Transplant: May 17 🍅 Harvest: Jul 26 – Sep 27

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 Putnam County

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

Soil pH

Your soil pH (5.6–7.0) is within Eggplant's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Eggplant.

How to Plant Eggplant

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

Succession Planting Eggplant

3
successive plantings in your 181-day season

Sow every 7.4 weeks. Last sowing by Jul 23 to harvest before frost.

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.9″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 273 gal / 100 sq ft

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 1.7" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.9" 0" ❄️ Dormant
Apr 4.8" 4.1" 0.7" 💧 Light watering
May 4.8" 4.4" 0.4" 💧 Light watering
Jun 4.8" 5.4" 0" ✅ Rainfall sufficient
Jul 4.8" 3.9" 0.9" 💧 Light watering
Aug 4.8" 4.1" 0.7" 💧 Light watering
Sep 4.8" 3.6" 1.2" 💧 Light watering
Oct 4.8" 3.2" 1.6" 💧 Light watering
Nov 2.7" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Putnam 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 2,217 GDD Excellent fit

Eggplant Planting Timeline — Putnam County, MO

Eggplant Planting Calendar

Activity When Date Range
Start Indoors February 7 Feb 7 – Feb 21
Transplant Outdoors May 2 May 2 – May 16
Direct Sow April 25 Apr 25 – May 16
Harvest July 11 Jul 11 – Sep 12

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · Only during dry spells

📅 Days to Maturity

65–85 days

🧪 Soil pH

Needs 5.5–7 · Your soil: ideal

🗺️ USDA Zone

Zone 5b

📆 Growing Season

181 days in Putnam County

Growing Tips for Eggplant in Putnam County

Direct sow Eggplant outdoors after April 18 in Putnam 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.

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 Putnam County, MO?

Putnam County is in Zone 5b with an average last frost of April 18. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.

What planting zone is Putnam County, MO?

Putnam County, Missouri is in USDA Hardiness Zone 5b. The average last spring frost is April 18 and first fall frost is October 16.

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Your Putnam County Garden Planner — Free

A 24-page printable planner built for Putnam 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.

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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 Putnam County, MO. 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.