When to plant tomato in Phoenix

Where are you growing?

Tight fit

Comfortable in greenhouse

Tight fit in a cold frame

Tomato in Phoenix is doable with planning outdoors. 56 suitable days are enough for fast varieties (55 days) but not slow ones (90 days).

Start indoors: January 23 – March 19
Transplant outside: March 24 – May 18
Harvest: May 18 – August 16
Season vs crop: 56 grow days vs 55–90 needed

Tomato in Phoenix is doable with planning outdoors. 56 suitable days are enough for fast varieties (55 days) but not slow ones (90 days).

Start seeds indoors January 23 – March 19, then transplant March 24 – May 18 so the crop can finish outdoors.

Planting conditions

Start indoors
Harden off
Transplant outside
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 row56

Days to harvest55–90 days from transplant

Jan 23 – Mar 19

Start indoors

Mar 17 – Mar 23

Harden off

March 24

Transplant outside

Mar 25 – May 17

Grow outdoors

May 18 – Aug 16

Harvest

Activity	Window	Notes
Start indoors	Jan 23 – Mar 19	Sow indoors before the outdoor window.
Harden off	Mar 17 – Mar 23	Acclimate seedlings outdoors before planting.
Transplant outside	March 24	Move plants outside on this day (start of the plant-out window).
Grow outdoors	Mar 25 – May 17	Plants grow outdoors until harvest.
Harvest	May 18 – Aug 16	Expected harvest from typical days to harvest.

Blue fill is usually too cold for this plant. 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 (70 – 84 °F) and tolerable (55 – 95 °F) 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

Frost-free days365

Earliest indoor seed startJanuary 23

Latest indoor seed startMarch 19

Transplant outdoorsMarch 24 – May 18

Direct sow windownot recommended here

Suitable growing windowMarch 24 – May 18 (56 days)

Expected harvestMay 18 – August 16

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: 55–90 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 Tomato: Mar 24 – May 18 (56 days)

Planting window for Tomato: Mar 24 – May 18 (56 days)

Usually too cold: Jan 1 – Mar 22; 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 13 · Mar 23 – Mar 29

Average 50 to 77 °F · Possible 39 to 96 °F

Growing: too cold (inside window)

Planting: suitable

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 Tomato 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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