When to plant chili pepper in St. Louis

In St. Louis, typical last spring frost is April 1 and typical first fall frost is November 10. Typical last spring frost: April 1. Chili pepper in St. Louis is a good fit outdoors. The suitable growing window of 145 days covers the 60–100 days this plant usually needs.

Chili pepper

How to grow Chili pepper St. Louis climate Weekly temperatures and windows

Where are you growing?

Comfortable

Comfortable in greenhouse

Comfortable in a cold frame

Chili pepper in St. Louis is a good fit outdoors. The suitable growing window of 145 days covers the 60–100 days this plant usually needs.

Start indoors: February 25 – April 18
Transplant outside: April 29 – June 20
Harvest: June 28 – October 31
Season vs crop: 145 grow days vs 60–100 needed
Typical frost (last spring – first fall): April 1 – November 10

Chili pepper in St. Louis is a good fit outdoors. The suitable growing window of 145 days covers the 60–100 days this plant usually needs.

Planting conditions

Start indoors
Grow indoors
Harden off
Transplant outside
Grow outdoors
Harvest

Local activity windows for this place and growing method. Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost.

Suitable growing days in a row145

Days to harvest60–100 days from transplant

Feb 25 – Apr 18

Start indoors

Apr 19 – Apr 21

Grow indoors

Apr 22 – Apr 28

Harden off

April 29

Transplant outside

Apr 30 – Jun 27

Grow outdoors

Jun 28 – Oct 31

Harvest

Activity	Window	Notes
Start indoors	Feb 25 – Apr 18	Sow indoors before the outdoor window.
Grow indoors	Apr 19 – Apr 21	Seedlings grow indoors until harden or transplant.
Harden off	Apr 22 – Apr 28	Acclimate seedlings outdoors before planting.
Transplant outside	April 29	Move plants outside on this day (start of the plant-out window).
Grow outdoors	Apr 30 – Jun 27	Plants grow outdoors until harvest.
Harvest	Jun 28 – Oct 31	Expected harvest from typical days to harvest.

Start indoors
Grow indoors
Harden off
Transplant outside
Grow outdoors
Harvest

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost (35 seasons (1991–2025)). Adjust a week or two for your conditions.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (21 – 32 °C70 – 90 °F21 – 32 °C (70 – 90 °F)) and tolerable (16 – 35 °C61 – 95 °F16 – 35 °C (61 – 95 °F)) ranges.

Ideal / plantable
Tolerable
Too cold
Too hot
Outside window

Planting uses sow / plant-out rules; growing shows daytime air against this plant’s ideal and tolerable ranges.

Key dates

Typical last spring frostApril 1

Low-risk last spring frostApril 15

Typical first fall frostNovember 10

Low-risk first fall frostOctober 31

Frost-free days222

Earliest indoor seed startFebruary 25

Latest indoor seed startApril 18

Transplant outdoorsApril 29 – June 20

Direct sow windownot recommended here

Suitable growing windowApril 29 – September 20 (145 days)

Expected harvestJune 28 – October 31

How these dates are judged

Ideal conditions: Daytime air from 21 – 32 °C70 – 90 °F21 – 32 °C (70 – 90 °F).
Suitable conditions: Daytime air from 16 – 35 °C61 – 95 °F16 – 35 °C (61 – 95 °F).
Last frost and first frost: Typical spring and fall frost dates for St. Louis, shown in the key dates.
Days to harvest: 60–100 days from transplant, from typical days to harvest.
Sowing window: Dated sow and harvest bars use frost dates, soil minima, night limits, and last-sow count-back from typical crop timing. Air ratings on the weekly chart colour only weeks inside that same window — see weekly temperatures and windows.

Other plants for St. Louis

Calculated by Plan & Plant. Method. Data 35 seasons (1991–2025).

Frost and suitability dates are typical figures from climate statistics.

Based on 35 years (1991–2025) of ERA5-Land data from Open-Meteo, for an area of about 10 km. Typical dates, not a guarantee.

Dates for St. Louis use ERA5-Land cell 38.63, -90.20. How we calculated this · Algorithm 2026-10-season-10.

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