When to plant sweet potato in Phoenix

In Phoenix, typical last spring frost is January 17 and typical first fall frost is December 22. Typical last spring frost: January 17. Sweet potato in Phoenix is not realistic outdoors: 60 suitable days are fewer than the 85 days this plant usually needs.

Sweet potato

How to grow Sweet potato Phoenix climate Weekly temperatures and windows

Where are you growing?

Not realistic outdoors

Not realistic in greenhouse

Tight fit in a cold frame

Sweet potato in Phoenix is doable with planning in a cold frame. 85 suitable days are enough for fast varieties (85 days) but not slow ones (140 days).

When to plantFebruary 25 – April 21

Harvest: May 21 – September 8
Season vs crop: 85 grow days vs 85–140 needed
Typical frost (last spring – first fall): January 9 – January 7

Sweet potato in Phoenix is doable with planning in a cold frame. 85 suitable days are enough for fast varieties (85 days) but not slow ones (140 days).

Start slips January 14 – March 10, then transplant February 25 – April 21 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

Suitable growing days in a row85

Days to harvest85–140 days from planting

No planting window is recorded for this place.

Too cold
Frost line

Blue fill is usually too cold for this plant. Dashed lines are typical last and first frost (35 seasons (1991–2025)). 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 (21 – 32 °C70 – 90 °F21 – 32 °C (70 – 90 °F)) and tolerable (16 – 35 °C61 – 95 °F16 – 35 °C (61 – 95 °F)) ranges, from modelled cover temperatures for the growing method you selected.

Ideal / plantable
Tolerable
Too cold
Too hot
Outside window

Planting uses sow / plant-out rules; growing shows daytime air against this plant’s ideal and tolerable ranges.

Key dates

Typical last spring frostJanuary 9

Low-risk last spring frostJanuary 15

Typical first fall frostJanuary 7

Low-risk first fall frostDecember 30

Frost-free days362

Earliest indoor seed startJanuary 14

Latest indoor seed startMarch 10

Transplant outdoorsFebruary 25 – April 21

Direct sow windownot recommended here

Suitable growing windowFebruary 25 – May 20 (85 days)

Expected harvestMay 21 – September 8

How these dates are judged

Ideal conditions: Daytime air from 21 – 32 °C70 – 90 °F21 – 32 °C (70 – 90 °F).
Suitable conditions: Daytime air from 16 – 35 °C61 – 95 °F16 – 35 °C (61 – 95 °F).
Last frost and first frost: Typical spring and fall frost dates for Phoenix, shown in the key dates.
Days to harvest: 85–140 days from planting, 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. Air ratings on the weekly chart colour only weeks inside that same window — see weekly temperatures and windows.

Other plants for Phoenix

Calculated by Plan & Plant. Method. Data 35 seasons (1991–2025).

Frost and suitability dates are typical figures from climate statistics.

Based on 35 years (1991–2025) of ERA5-Land data from Open-Meteo, for an area of about 10 km. Typical dates, not a guarantee.

Dates for Phoenix use ERA5-Land cell 33.45, -112.07. How we calculated this · Algorithm 2026-10-season-10.

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