When to plant tomatoes in Jefferson City: 23 April – 15 July

In Jefferson City, tomato: sow for seedlings from 9 February to 24 May; plant into a greenhouse from 2 April to 15 July; plant out into open ground from 23 April to 15 July.

Tomato in Jefferson City: soil, season and weather

In Jefferson City the soil, not frost, sets the date: the last frost is over around 5 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 23 April, 18 days later.

Last spring frost	5 April
Top 7 cm of soil at 15 °C	23 April, 18 days after the last frost
Into an unheated greenhouse	2 April – 15 July; April outside: 8 °C at night, 19.9 °C by day; card 16–27 °C
First autumn frost	4 November, 195 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	2 July – 23 September
Days left for picking	125
Daylight	11:22 on 2 March, 13:30 on 23 April
Watering outdoors when fruiting (card)	every 3 days; the driest month, November, has 7 rainy days

Tomato in Jefferson City: care after planting

Planted on 23 April: in the first weeks water every 4 days.

Feeding, by the card’s schedule from that day:

23 April — feed: balanced (NPK)
21 May — feed: nitrogen

Pests and diseases of tomato to watch for:

Dates count from the first planting day of the window above; a later planting moves them by as many days.

Weather in Jefferson City during the tomato season

Days average above the tomato card's 16–27 °C in June–September (28.4–31.9 °C). Months that stay below 16 °C even by day on average: November (14 °C). Nights average below 16 °C in April, May and October, November (4.1–14 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
April	19.9	8	134	11	13:11
May	24.5	14	124	14	14:15
June	30.6	19.4	122	11	14:51
July	31.9	21.5	111	11	14:37
August	30.6	20.3	100	10	13:42
September	28.4	17.4	66	7	12:29
October	21.4	10.9	95	9	11:15
November	14	4.1	64	7	10:06

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

Around Jefferson City, Joplin is 12 days earlier and Peoria 9 days later.

City	Distance	Date	Difference
St. Louis	172 km	18 April – 15 July	5 days earlier
Kansas City	216 km	18 April – 12 July	5 days earlier
Springfield	258 km	26 April – 12 July	3 days later
Joplin	263 km	11 April – 12 July	12 days earlier
Topeka	309 km	16 April – 9 July	7 days earlier
Peoria	324 km	2 May – 11 July	9 days later

Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

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