GreenlyWhen to plant watermelons in San Jose: from 25 April
In San Jose, watermelon: sow for seedlings from 7 March; plant into a greenhouse from 4 April; plant out into open ground from 25 April. There is no autumn frost here, so the frost dates set no end to the window.
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Watermelon in San Jose: soil, season and weather
In San Jose the soil, not frost, sets the date: the last frost is over around 24 February, but the top 7 cm of soil reaches 18 °C — the minimum on the watermelon card — only around 25 April, 60 days later. San Jose has no autumn frost in the median year, so frost does not end the season.
| Last spring frost | 24 February |
|---|---|
| Top 7 cm of soil at 18 °C | 25 April, 60 days after the last frost |
| Into an unheated greenhouse | from 4 April; April outside: 8.6 °C at night, 20.8 °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 23 June |
| Daylight | 12:26 on 28 March, 13:30 on 25 April |
| Watering outdoors when fruiting (card) | every 5 days; the driest month, June, has 0 rainy days |
The same dates in San Jose hold for Cucumber, Bell Pepper, Eggplant, Zucchini and Pumpkin.
Watermelon in San Jose: care after planting
Planted on 25 April: in the first weeks water every 5 days.
Feeding, by the card’s schedule from that day:
- 25 April — 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 San Jose during the watermelon season
No month of the season averages above the watermelon card's 18–35 °C by day; the warmest, July, averages 30.2 °C. Nights average below 18 °C in every month of the season, from 8.6 °C to 15 °C.
| Month | Day, °C | Night, °C | Rain, mm | Rainy days | Daylight on the 15th |
|---|---|---|---|---|---|
| April | 20.8 | 8.6 | 27 | 4 | 13:08 |
| May | 24.4 | 10.8 | 16 | 3 | 14:10 |
| June | 28.7 | 13.3 | 0 | 0 | 14:43 |
| July | 30.2 | 14.5 | 0 | 0 | 14:30 |
| August | 30.1 | 15 | 1 | 0 | 13:38 |
| September | 28.7 | 14.5 | 5 | 1 | 12:28 |
ERA5 2016–2025, Open-Meteo
Watermelon in nearby cities
Around San Jose, Bakersfield is 23 days earlier and Carson City 18 days later.
| City | Distance | Date | Difference |
|---|---|---|---|
| Stockton | 87 km | 24 April – 24 August | 1 day earlier |
| Sacramento | 142 km | 24 April – 1 September | 1 day earlier |
| Fresno | 199 km | 10 April – 26 August | 15 days earlier |
| Carson City | 274 km | 13 May – 13 July | 18 days later |
| Reno | 303 km | 29 April – 19 July | 4 days later |
| Bakersfield | 338 km | 2 April – 4 September | 23 days earlier |
Where to buy watermelon plants and seeds near San Jose
Buy plants ready to set out from 25 April (from 4 April for an unheated greenhouse); seed for raising your own is sown from 7 March. Within 15 km of San Jose OpenStreetMap lists 11 garden centres, 1 farm-supply shop, 1 plant nursery, 16 markets and 1 farm shop (collected 20 October 2026).
- The Home Depot — garden centre
7 km - Payless Nursery — garden centre
7 km - The Home Depot Garden Center — garden centre
9 km - San Pedro Square Market — market
1 km · sanpedrosquaremarket.com
Places: © OpenStreetMap contributors, ODbL.
- How to grow watermelon
- All frost dates and weather of San Jose
- Shops and markets: San Jose
- Selling a surplus in the United States
- Moon planting calendar for November 2026
- How we calculate the dates
Questions
When to plant watermelons in San Jose?
In San Jose, watermelon: sow for seedlings from 7 March; plant into a greenhouse from 4 April; plant out into open ground from 25 April. There is no autumn frost here, so the frost dates set no end to the window.
When to sow watermelons for seedlings in San Jose?
Sow for seedlings from 7 March.
