GreenlyWhen to plant tomato in St. Louis
In St. Louis, tomato: sow seedlings around 30 January for the greenhouse and around 20 February for open ground; plant into a greenhouse around 28 March; plant out into open ground around 18 April.
Last spring frost around 6 April, first autumn frost around 4 November. Frost-free days: 212 days.
The dates follow the Greenly calendar: open ground a week after the last frost once the soil is warm enough for the crop, frost-hardy crops three weeks before it, an unheated greenhouse three weeks earlier, seedlings sown so they are ready on the day. In a cold year allow a week or two more.