When to Plant Eggplant in St. Louis City, MO
Your May game plan for St. Louis City, Missouri
May is a pivotal month for St. Louis City, Missouri gardens. Focus on these tasks first and you'll set up the rest of the season for success.
June will be here before you know it — start on
- Starting indoors: eggplant
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.
St. Louis City, Missouri is in USDA Zone 7a. The average last spring frost is April 8 and the first fall frost is October 27, giving you a growing season of approximately 202 days.
At an elevation of 612 feet, St. Louis City receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Eggplant during the growing season.
St. Louis City Soil Profile
Soil Type
Silt Loam
Soil pH
5.8-6.8
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 St. Louis City
How your county's soil matches Eggplant's growing requirements.
Soil pH
Your soil pH (5.8–6.8) is within Eggplant's preferred range (5.5–7.0).
Soil Texture
The silt loam soil in St. Louis City is excellent for Eggplant — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.9%). Annual compost additions will help Eggplant.
How to Plant Eggplant
Succession Planting Eggplant
Sow every 7.4 weeks. Last sowing by Aug 03 to harvest before frost.
Plant Water Budget
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 | — | 2" | 0" | ❄️ Dormant |
| Feb | — | 2.1" | 0" | ❄️ Dormant |
| Mar | — | 3.2" | 0" | ❄️ Dormant |
| Apr | 4.8" | 3.5" | 1.3" | 💧 Light watering |
| May | 4.8" | 5.2" | 0" | ✅ Rainfall sufficient |
| Jun | 4.8" | 5.9" | 0" | ✅ Rainfall sufficient |
| Jul | 4.8" | 3.9" | 0.9" | 💧 Light watering |
| Aug | 4.8" | 4.4" | 0.4" | 💧 Light watering |
| Sep | 4.8" | 3.2" | 1.6" | 💧 Light watering |
| Oct | 4.8" | 2.8" | 2" | 💧 Light watering |
| Nov | — | 2.6" | 0" | ❄️ Dormant |
| Dec | — | 2.1" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in St. Louis City). 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 Planting Timeline — St. Louis City, MO
Eggplant Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | February 4 | Feb 4 – Feb 18 |
| Transplant Outdoors | April 22 | Apr 22 – May 6 |
| Direct Sow | April 15 | Apr 15 – May 6 |
| Harvest | July 1 | Jul 1 – Sep 2 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | Start Indoors |
| March | — |
| April | Transplant Outdoors Direct Sow |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · 1-2 times/week
📅 Days to Maturity
65–85 days
🧪 Soil pH
Needs 5.5–7 · Your soil: ideal
🗺️ USDA Zone
Zone 7a
📆 Growing Season
202 days in St. Louis City
Growing Tips for Eggplant in St. Louis City
Direct sow Eggplant outdoors after April 08 in St. Louis City 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
Check more plant combinations with our Companion Planting Checker →
Eggplant in Other Locations
Frequently Asked Questions
When should I plant Eggplant in St. Louis City, MO?
St. Louis City is in Zone 7a with an average last frost of April 8. Plan your Eggplant planting based on this frost date — see the calendar above for exact timing.
What planting zone is St. Louis City, MO?
St. Louis City, Missouri is in USDA Hardiness Zone 7a. The average last spring frost is April 8 and first fall frost is October 27.
Your St. Louis City Garden Planner — Free
A 24-page printable planner built for St. Louis City (Zone 7a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.