When to plant parsley 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. Parsley in St. Louis is doable with planning outdoors. 75 suitable days are enough for fast varieties (70 days) but not slow ones (80 days).

Parsley

How to grow Parsley St. Louis climate Weekly temperatures and windows

Where are you growing?

Tight fit

Not realistic in greenhouse

Comfortable in a cold frame

Parsley in St. Louis is doable with planning outdoors. 75 suitable days are enough for fast varieties (70 days) but not slow ones (80 days).

When to plantMarch 18 – May 12

Harvest: May 27 – July 31
Season vs crop: 75 grow days vs 70–80 needed
Typical frost (last spring – first fall): April 1 – November 10

Parsley in St. Louis is doable with planning outdoors. 75 suitable days are enough for fast varieties (70 days) but not slow ones (80 days).

Planting conditions

Direct sow
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 row75

Days to harvest70–80 days from seed

Mar 18 – May 12

Direct sow

May 13 – May 26

Grow outdoors

May 27 – Jul 31

Harvest

Activity	Window	Notes
Direct sow	Mar 18 – May 12	Plant outdoors in this window.
Grow outdoors	May 13 – May 26	Plants grow outdoors until harvest.
Harvest	May 27 – Jul 31	Expected harvest from typical days to harvest.

Direct sow
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 (15 – 21 °C59 – 70 °F15 – 21 °C (59 – 70 °F)) and tolerable (4 – 27 °C39 – 81 °F4 – 27 °C (39 – 81 °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

Outdoor sow dateMarch 18

Direct sow windowMarch 18 – May 12

Suitable growing windowMarch 18 – May 31 (75 days)

Expected harvestMay 27 – July 31

How these dates are judged

Ideal conditions: Daytime air from 15 – 21 °C59 – 70 °F15 – 21 °C (59 – 70 °F).
Suitable conditions: Daytime air from 4 – 27 °C39 – 81 °F4 – 27 °C (39 – 81 °F).
Last frost and first frost: Typical spring and fall frost dates for St. Louis, shown in the key dates.
Days to harvest: 70–80 days from seed, 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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