Greenly Garden

When to plant zucchini in Portland, Maine: 20 June – 18 August

In Portland, Maine, zucchini: sow for seedlings from 9 May to 28 July; plant into a greenhouse from 30 May to 18 August; plant out into open ground from 20 June to 18 August. For plants and seeds, the places nearby include Harmons Vegetable Stand (farm shop, 12 km); addresses and opening hours are below.

Zucchini in Portland, Maine: soil, season and weather

In Portland, Maine the soil, not frost, sets the date: the last frost is over around 15 April, but the top 7 cm of soil reaches 18 °C — the minimum on the zucchini card — only around 20 June, 66 days later.

Last spring frost15 April
Top 7 cm of soil at 18 °C20 June, 66 days after the last frost
First autumn frost4 November, 137 days after the start
Days in the bed to the first harvest (card)36
First harvest, if planted in this window26 July – 23 September
Days left for picking101
Daylight15:10 on 30 May, 15:27 on 20 June
Watering outdoors when fruiting (card)every 3 days; the driest month, September, has 9 rainy days

The same dates in Portland, Maine hold for Cucumber, Bell Pepper, Eggplant, Pumpkin and Watermelon.

Zucchini in Portland, Maine: care after planting

Planted on 20 June: in the first weeks water every 4 days.

Pests and diseases of zucchini to watch for:

Weather in Portland, Maine during the zucchini season

About 559 mm of rain falls in the season; September is the driest month (80 mm) and October the wettest (121 mm).

MonthDay, °CNight, °CRain, mmRainy daysDaylight on the 15th
June22.613.9851115:25
July26.117.9951115:08
August25.317.2831014:01
September21.713.780912:33
October15.68.11211011:05
November8.41.29599:42

ERA5 2016–2025, Open-Meteo

Zucchini in nearby cities

Around Portland, Maine, Boston is 22 days earlier and Bangor 5 days later.

CityDistanceDateDifference
Augusta82 km22 June – 17 August2 days later
Concord115 km1 June – 14 August19 days earlier
Manchester (United States)122 km30 May – 16 August21 days earlier
Boston159 km29 May – 27 August22 days earlier
Bangor179 km25 June – 17 August5 days later
Montpelier196 km20 June – 31 Julysame day

Where to buy zucchini plants and seeds near Portland, Maine

Buy plants ready to set out from 20 June to 18 August (from 30 May to 18 August for an unheated greenhouse); seed for raising your own is sown from 9 May to 28 July. Within 15 km of Portland, Maine OpenStreetMap lists 5 garden centres, 6 markets and 1 farm shop (collected 20 October 2026).

Places: © OpenStreetMap contributors, ODbL.

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.

Questions

When to plant zucchini in Portland, Maine?

In Portland, Maine, zucchini: sow for seedlings from 9 May to 28 July; plant into a greenhouse from 30 May to 18 August; plant out into open ground from 20 June to 18 August.

When to sow zucchini for seedlings in Portland, Maine?

Sow for seedlings from 9 May to 28 July.

When is the last spring frost in Portland, Maine?

Last spring frost around 15 April, first autumn frost around 4 November.

Other crops in Portland, Maine, with their dates