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When to plant Cumin in Ballwin, MO

Ballwin's climate puts the Cumin spring window between March 30 and April 20. most warm-season crops establish quickly once soil holds above 60°F. A second sowing from August 15 to August 29 extends the harvest into fall.

When to Plant Cumin in Ballwin, MO

St. Louis County, Missouri Zone 7a July

Top priorities for St. Louis County, Missouri gardeners in July

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

Avg. last frost April 13
Avg. first frost October 24
Soil temp (4") 82°F
Watering Low
Pest pressure High
Daylight 14.4 hrs
  1. Harvest cumin as they ripen

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

A few tasks this July that'll pay off in August
  • First harvests: cumin
  • Fall sowing: cumin

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Cumin is a warm-season annual herb whose seeds are one of the most widely used spices globally. It requires a long, hot growing season of 3-4 months.

Ballwin, Missouri is in USDA Zone 7a. The average last spring frost is April 13 and the first fall frost is October 24, giving you a growing season of approximately 194 days.

At an elevation of 895 feet, St. Louis County receives approximately 40.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Cumin during the growing season.

Ballwin, MO (Zone 7a) Moderate season
194 days
Last Spring Frost April 13
194 growing days
First Fall Frost October 24

Ballwin Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.6

Drainage

Well Drained

Cumin Planting Risk Windows

Early Start (70% safe) ✓ Fits season (33 days to spare)
Start indoors: Mar 2 Transplant: Mar 30 🍅 Harvest: Jul 13 – Sep 14
Recommended (50%) ✓ Fits season (33 days to spare)
Start indoors: Mar 9 Transplant: Apr 6 🍅 Harvest: Jul 20 – Sep 21
Safe Start (90%) ✓ Fits season (32 days to spare)
Start indoors: Mar 22 Transplant: Apr 19 🍅 Harvest: Aug 2 – Oct 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 Ballwin

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

Soil pH

Your soil pH (5.4–6.6) overlaps with Cumin's range (6.0–8.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.0%). Annual compost additions will help Cumin.

How to Plant Cumin

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Cumin Water Budget

Plant needs
0.5″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Cumin

Cumin needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Cumin Needs Rainfall You Supplement Action
Jan 1.6" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 2.2" 3.7" 0" ✅ Rainfall sufficient
May 2.2" 5.2" 0" ✅ Rainfall sufficient
Jun 2.2" 4.5" 0" ✅ Rainfall sufficient
Jul 2.2" 4.7" 0" ✅ Rainfall sufficient
Aug 2.2" 4.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.4" 0" ✅ Rainfall sufficient
Oct 2.2" 3.5" 0" ✅ Rainfall sufficient
Nov 2.5" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

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

Cumin 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.

Cumin needs ~1,595 GDD — county provides 2,813 GDD Excellent fit

Cumin Planting Timeline — Ballwin, MO

Cumin Planting Calendar

Activity When Date Range
Start Indoors March 9 Mar 9 – Mar 23
Transplant Outdoors April 6 Apr 6 – Apr 20
Direct Sow March 30 Mar 30 – Apr 20
Harvest July 20 Jul 20 – Sep 21
Fall Sowing August 15 Aug 15 – Aug 29

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–8 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

194 days in St. Louis County

Growing Tips for Cumin in Ballwin

Direct sow Cumin outdoors after April 13 in St. Louis County when soil has warmed and frost danger has passed.

Common pests for Cumin in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Start seeds indoors 4 weeks before last frost. Transplant after all danger of frost. Harvest when seed heads turn brown. Requires consistent warmth for proper seed development.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

When should I plant Cumin in Ballwin, MO?

In Ballwin, MO, plant Cumin after the last frost (around April 13) and before the first frost (around October 24). Best results when soil holds above 50°F.

What growing zone is Ballwin, MO for Cumin?

Ballwin sits in USDA Zone 7a. Cumin grows reliably in zones 5a through 11b, so it's a good fit here.

Can Cumin grow in Ballwin's climate?

Yes — Cumin grows well in Ballwin's temperate climate. Ballwin averages a 194-day frost-free season, with last frost around April 13 and first frost around October 24.

🌱

Your St. Louis County Garden Planner — Free

A 22-page printable planner built for St. Louis County (Zone 7a). 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 St. Louis County, MO. Local conditions may vary. Last updated: July 2026.