GreenlyWhen to plant watermelons in St. Petersburg: from 25 January
In St. Petersburg, watermelon: sow for seedlings from 7 December; plant into a greenhouse from 4 January; plant out into open ground from 25 January. There is no autumn frost here, so the frost dates set no end to the window. For plants and seeds, the places nearby include Dolins Garden Center (garden centre, 3 km) and Corner Garden Produce (farm shop, 6 km); addresses and opening hours are below.
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Watermelon in St. Petersburg: soil, season and weather
In St. Petersburg frost, not soil, sets the date: the top 7 cm of soil averages 18 °C — the minimum on the watermelon card — already in the first week of January, before the last frost on 18 January, so planting waits only for the week after that frost. St. Petersburg has no autumn frost in the median year, so frost does not end the season.
| Last spring frost | 18 January |
|---|---|
| Top 7 cm of soil at 18 °C | already in the first week of January |
| Into an unheated greenhouse | from 4 January; January outside: 12.7 °C at night, 20 °C by day; card 18–35 °C |
| Days in the bed to the first harvest (card) | 59 |
| First harvest, if planted in this window | from 25 March |
| Daylight | 10:23 on 28 December, 10:44 on 25 January |
| Watering outdoors when fruiting (card) | every 5 days; the driest month, March, has 7 rainy days |
The same dates in St. Petersburg hold for Tomato, Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.
Watermelon in St. Petersburg: care after planting
Planted on 25 January: in the first weeks water every 5 days.
Feeding, by the card’s schedule from that day:
- 25 January — feed: balanced (NPK)
Pests and diseases of watermelon 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 St. Petersburg during the watermelon season
No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, June, averages 30.4 °C. Nights average below 18 °C in January (12.7 °C), February (15.3 °C) and March (16.8 °C).
| Month | Day, °C | Night, °C | Rain, mm | Rainy days | Daylight on the 15th |
|---|---|---|---|---|---|
| January | 20 | 12.7 | 70 | 7 | 10:34 |
| February | 22.7 | 15.3 | 53 | 6 | 11:13 |
| March | 24.5 | 16.8 | 47 | 7 | 11:58 |
| April | 27.1 | 19.5 | 63 | 7 | 12:49 |
| May | 29.6 | 22.3 | 92 | 10 | 13:31 |
| June | 30.4 | 24.7 | 159 | 21 | 13:54 |
ERA5 2016–2025, Open-Meteo
Watermelon in nearby cities
2 of the nearest cities share St. Petersburg's date.
| City | Distance | Date | Difference |
|---|---|---|---|
| Tampa | 25 km | 25 January – 14 September | same day |
| Orlando | 150 km | 25 January – 15 September | same day |
| Gainesville | 206 km | 18 February – 14 September | 24 days later |
| Jacksonville | 296 km | 11 February – 17 September | 17 days later |
| Tallahassee | 331 km | 24 February – 13 September | 30 days later |
| Savannah | 497 km | 25 February – 14 September | 31 days later |
Where to buy watermelon plants and seeds near St. Petersburg
Buy plants ready to set out from 25 January (from 4 January for an unheated greenhouse); seed for raising your own is sown from 7 December. Within 15 km of St. Petersburg OpenStreetMap lists 6 garden centres, 2 markets and 1 farm shop (collected 28 October 2026).
- Corner Garden Produce — farm shop
4th Avenue South 2300, 33712 Saint Petersburg · Tue–Sat 10:00–19:00 · 6 km - Jene's Tropicals — garden centre
8 km - All Seasons Landscaping — garden centre
8 km - Dolins Garden Center — garden centre
62nd Avenue North 801, 33702 Saint Petersburg · Mon–Sat 08:30–17:30; Sun 10:00–17:00 · 3 km
Places: © OpenStreetMap contributors, ODbL.
- How to grow watermelon
- All frost dates and weather of St. Petersburg
- Shops and markets: St. Petersburg
- Selling a surplus in the United States
- Moon planting calendar for November 2026
- How we calculate the dates
Questions
When to plant watermelons in St. Petersburg?
In St. Petersburg, watermelon: sow for seedlings from 7 December; plant into a greenhouse from 4 January; plant out into open ground from 25 January. There is no autumn frost here, so the frost dates set no end to the window.
When to sow watermelons for seedlings in St. Petersburg?
Sow for seedlings from 7 December.
