When to plant tomatoes in Boise: 27 April – 7 July

In Boise, tomato: sow for seedlings from 13 February to 16 May; plant into a greenhouse from 6 April to 7 July; plant out into open ground from 27 April to 7 July. For plants and seeds, the places nearby include North End Organic Nursery (garden centre, 4 km) and Zamzows (garden centre, 5 km); addresses and opening hours are below.

Tomato in Boise: soil, season and weather

In Boise the soil, not frost, sets the date: the last frost is over around 15 April, but the top 7 cm of soil reaches 15 °C — the minimum on the tomato card — only around 27 April, 12 days later.

Last spring frost	15 April
Top 7 cm of soil at 15 °C	27 April, 12 days after the last frost
Into an unheated greenhouse	6 April – 7 July; April outside: 4.5 °C at night, 17.6 °C by day; card 16–27 °C
First autumn frost	27 October, 183 days after the start
Days in the bed to the first harvest (card)	70
First harvest, if planted in this window	6 July – 15 September
Days left for picking	113
Daylight	11:25 on 6 March, 13:57 on 27 April
Watering outdoors when fruiting (card)	every 3 days; the driest month, July, has 1 rainy day

Tomato in Boise: care after planting

Planted on 27 April: in the first weeks water every 4 days.

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

27 April — feed: balanced (NPK)
25 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 Boise during the tomato season

Days average above the tomato card's 16–27 °C in June–September (27.9–35.1 °C). Nights average below 16 °C in April–June and September, October (4.5–13.9 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
April	17.6	4.5	34	7	13:24
May	23	9.1	42	8	14:42
June	29	13.9	22	4	15:25
July	35.1	19.2	3	1	15:08
August	33.7	18.1	6	1	14:01
September	27.9	13.1	12	3	12:33
October	18.2	6.3	26	5	11:05

ERA5 2016–2025, Open-Meteo

Tomato in nearby cities

All the nearest cities on our list plant tomato later than Boise; the closest date is in Salt Lake City, 10 days later.

City	Distance	Date	Difference
Elko	310 km	15 May – 23 June	18 days later
Idaho Falls	336 km	18 May – 24 June	21 days later
Missoula	400 km	3 June – 16 June	37 days later
Spokane	460 km	15 May – 25 June	18 days later
Helena	466 km	6 June – 13 June	40 days later
Salt Lake City	476 km	7 May – 6 July	10 days later

Where to buy tomato plants and seeds near Boise

Buy plants ready to set out from 27 April to 7 July (from 6 April to 7 July for an unheated greenhouse); seed for raising your own is sown from 13 February to 16 May. Within 15 km of Boise OpenStreetMap lists 4 garden centres, 2 farm-supply shops and 1 plant nursery (collected 20 October 2026).

Zamzows — garden centre
South Federal Way 3691, 83716 Boise · Mon–Fri 09:00–19:00; Sun 22:00–17:00; Sat 09:00–18:00 · 5 km
North End Organic Nursery — garden centre
West Chinden Boulevard 3777, 83714 Garden City · 4 km
Zamzows — garden centre
West Fairview Avenue 6313, 83704 Boise · 5 km
Cloverdale Nursery — garden centre
North Cloverdale Road 2528, 83713 Boise · 11 km

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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