When to plant green bean in Portsmouth

How to grow Green bean Portsmouth climate

Where are you growing?

Comfortable

Comfortable in greenhouse

Comfortable in a cold frame

Green bean in Portsmouth is a good fit outdoors. The suitable growing window of 106 days covers the 50–65 days this plant usually needs.

When to plantJune 1 – August 13

Harvest: July 21 – September 14
Season vs crop: 106 grow days vs 50–65 needed
Typical frost (last spring – first fall): March 9 – November 27

Green bean in Portsmouth is a good fit outdoors. The suitable growing window of 106 days covers the 50–65 days this plant usually needs.

Planting conditions

Direct sow
Harvest

Local activity windows for this place and growing method. Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost.

Suitable growing days in a row106

Days to harvest50–65 days from seed

Jun 1 – Aug 13

Direct sow

Jul 21 – Sep 14

Harvest

Activity	Window	Notes
Direct sow	Jun 1 – Aug 13	Plant outdoors in this window.
Harvest	Jul 21 – Sep 14	Expected harvest from typical days to harvest.

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost. Adjust a week or two for your conditions.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (21 – 35 °C) and tolerable (13 – 38 °C) ranges.

Planting uses sow / plant-out rules (frost, soil germination, night, and last-sow): green when plantable, blue diagonal when nights or soil are too cold, amber cross-hatch when too hot, faint for other calendar limits. Growing shows daytime air against this plant’s ideal and tolerable ranges across the year.

Key dates

Typical last spring frostMarch 9

Safer last spring frostApril 8

Typical first fall frostNovember 27

Safer first fall frostNovember 20

Frost-free days262

Outdoor sow dateJune 1

Direct sow windowJune 1 – August 13

Suitable growing windowJune 1 – September 14 (106 days)

Expected harvestJuly 21 – September 14

How these dates are judged

Ideal conditions: Daytime air from 21 – 35 °C.
Suitable conditions: Daytime air from 13 – 38 °C.
Last frost and first frost: Typical spring and fall frost dates for Portsmouth, shown in the key dates.
Days to harvest: 50–65 days from seed, from typical days to harvest.
Sowing window: Dated sow and harvest bars use frost dates, soil minima, night limits, and last-sow count-back from typical crop timing. The year strip and weekly chart use the same window: air ratings only colour weeks inside it.

Growing window for Green bean: Jun 1 – Sep 14 (106 days)

Planting window for Green bean: Jun 1 – Aug 13 (74 days)

Usually too cold: Jan 1 – May 31; Sep 21 – Dec 31

Outdoors: weekly temperatures and windows

Temperatures across the year for Portsmouth. Shaded bands are this plant’s ideal and tolerable daytime air ranges. Growing is daytime air suitability; Planting is sow / plant-out conditions (same colour language). Window brackets mark each stretch.

Ideal range
Tolerable range
Possible min to max
Average min to max
Suitable
Tolerable
Too cold
Too hot

Selected week · tap a week or use the arrows

Week 23 · Jun 1 – Jun 7

Average 11 to 18 °C · Possible 8 to 24 °C

Growing: too cold (inside window)

Planting: suitable

A week is in range when its average low and high sit inside the tolerance band 13 to 38 °C; it is suitable when that average range also overlaps the ideal 21 to 35 °C band and possible readings stay within 0 °C to 38 °C. Crossing a possible limit, or missing the ideal band, makes it tolerable; any chance of frost (possible low below 0 °C) makes it too cold. When a sowing window is calculated, weeks outside that window are uncoloured even if air is in range.

Based on average frost dates.

Show all 53 weeks

Cover method weekly charts

Outdoor weekly chart is above. Open a cover chart only if you grow under fleece, a cold frame, or an unheated greenhouse.

Other plants for Portsmouth

Calculated by Plan & Plant · Method · Data 2019–2026

Frost and suitability dates are typical figures from climate statistics. Microclimates vary; they are not a guarantee.

How we calculated this

Data: ERA5-Land via Open-Meteo, cell 50.80, -1.09, years 2019–2026 (not a 30-year climate normal yet).
Typical and safer dates: Typical last frost is the date after which half of winters in this sample had no more frost; safer is later in the sample so fewer winters still frosted.
Crop rule: Local windows for Green bean from frost dates, temperature ratings, and crop timing rules.
Confidence: Provisional — short or thin sample for this place.
Full methodology (algorithm 2026-10-season-5).

Report a problem