When to plant bell pepper in Phoenix

Where are you growing?

Not realistic outdoors

Comfortable in greenhouse

Tight fit in a cold frame

Bell pepper in Phoenix is doable with planning in a cold frame. 63 suitable days are enough for fast varieties (60 days) but not slow ones (85 days).

Start indoors: July 7 – August 31
Transplant into cold frame: September 15 – November 9
Harvest: November 14 – February 2
Season vs crop: 63 grow days vs 60–85 needed

Bell pepper in Phoenix is doable with planning in a cold frame. 63 suitable days are enough for fast varieties (60 days) but not slow ones (85 days).

Start seeds indoors July 7 – August 31, then transplant September 15 – November 9 so the crop can finish in a cold frame.

Estimate. Protection varies with the cover, the weather and how you vent it.

A closed cold frame keeps nights up to about 3–6 °C warmer than outside. Open it on sunny days.

Cover dates are modelled from weather-model data using published greenhouse studies. They are not measured in your greenhouse. A max–min thermometer inside will tell you more.

Planting conditions

Start indoors
Grow indoors
Harden off
Transplant into cold frame
Grow outdoors
Harvest

Local activity windows for this place and growing method. Blue fill is usually too cold for this plant.

Suitable growing days in a row63

Days to harvest60–85 days from transplant

Jul 7 – Aug 31

Start indoors

Sep 1 – Sep 7

Grow indoors

Sep 8 – Sep 14

Harden off

September 15

Transplant into cold frame

Sep 16 – Nov 13

Grow outdoors

Nov 14 – Feb 2

Harvest

Activity	Window	Notes
Start indoors	Jul 7 – Aug 31	Sow indoors before the outdoor window.
Grow indoors	Sep 1 – Sep 7	Seedlings grow indoors until harden or transplant.
Harden off	Sep 8 – Sep 14	Acclimate seedlings outdoors before planting.
Transplant into cold frame	September 15	Move plants outside on this day (start of the plant-out window).
Grow outdoors	Sep 16 – Nov 13	Plants grow outdoors until harvest.
Harvest	Nov 14 – Feb 2	Expected harvest from typical days to harvest.

Blue fill is usually too cold for this plant. Adjust a week or two for your conditions.

Protected frost and sowing dates are modelled estimates from weather-model data and published greenhouse studies, not measured in your greenhouse. A max–min thermometer inside will tell you more.

Planting and growing across the year

Planting is the sow / plant-out window. Growing is daytime air versus this plant’s ideal (70 – 84 °F) and tolerable (55 – 95 °F) ranges, from modelled cover temperatures for the growing method you selected.

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

Frost-free days365

Earliest indoor seed startJuly 7

Latest indoor seed startAugust 31

Transplant outdoorsSeptember 15 – November 9

Direct sow windownot recommended here

Suitable growing windowMarch 17 – May 18 (63 days)

Expected harvestNovember 14 – February 2

How these dates are judged

Ideal conditions: Daytime air from 70 – 84 °F.
Suitable conditions: Daytime air from 55 – 95 °F.
Last frost and first frost: Typical spring and fall frost dates for Phoenix, shown in the key dates.
Days to harvest: 60–85 days from transplant, 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 Bell pepper: Apr 5 – May 18 (44 days)

Planting window for Bell pepper: Apr 5 – May 30 (56 days)

Usually too cold: Oct 26 – Dec 31

Outdoors: weekly temperatures and windows

Temperatures across the year for Phoenix. 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 14 · Mar 30 – Apr 5

Average 53 to 79 °F · Possible 38 to 97 °F

Growing: too cold

Planting: too cold

A week is in range when its average low and high sit inside the tolerance band 55 to 95 °F; it is suitable when that average range also overlaps the ideal 70 to 84 °F band and possible readings stay within 32 °F to 95 °F. Crossing a possible limit, or missing the ideal band, makes it tolerable; any chance of frost (possible low below 32 °F) 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 Phoenix

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 33.45, -112.07, 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 Bell pepper from frost dates, temperature ratings, and crop timing rules.
Confidence: Provisional — short or thin sample for this place.
Full methodology (algorithm 2026-10-season-6).

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