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Potatoes

When to start, transplant and harvest potatoes, as 4 university extension services put it, and what that means in each zone.

Family
Solanaceae5
Type
Tuber
Rules
6
Last reviewed
Garden experts do not always agree, so I show every rule side by side.

Five digits. The calendar is computed on your device.

Spring timing, source by source

Every rule counts from the last spring frost, so the same rule gives different dates in different gardens. Here are the rules themselves before any dates are worked out.

  1. Colorado StateSow outdoors
  2. Utah StateSow outdoors
  3. Texas A&M (E-502)Sow outdoors
  • Plant outdoors
Figure 1. How each extension source times potatoes in spring, in weeks before or after the last frost. Sources disagree; each bar is one publication's rule, shown as written.

Fall timing, source by source

Fall rules count from the first fall frost.

  1. Texas A&M (E-502)Plant for fall
  • Plant outdoors
Figure 2. How each extension source times potatoes in fall, in weeks before or after the first frost. Rules written for warm states sit weeks earlier than those for cold ones.
Table 1. Planting rules for potatoes, as published.
SourceWritten forWhatWhen
Colorado State1COSow outdoorsFrom 2 wk before to on the last frost
Utah State2UTSow outdoors2 weeks before last frost
Texas A&M (E-502)6TXSow outdoors4-6 weeks before last frost
Texas A&M (E-502)6TXPlant for fall14-16 weeks before first frost
Nebraska (G1343)4NEPlant for fallCount back days to maturity + 14-day fall factor (+14 for tender crops) from the first frost

Potatoes by hardiness zone

Applied to the frost records of every ZIP in each zone. The zone median is a starting point; your own station can be weeks earlier or later.

Table 2. Outdoor planting for potatoes by zone, using the Colorado State rule. Linked zones have their own page.
ZoneWhatZone medianAcross most of the zone
4aSow outdoorsApr 28 – May 12Apr 21 – May 24
4bSow outdoorsApr 24 – May 8Apr 17 – May 25
5aSow outdoorsApr 19 – May 3Apr 12 – May 20
5bSow outdoorsApr 17 – May 1Apr 7 – May 17
6aSow outdoorsApr 14 – Apr 28Apr 2 – May 10
6bSow outdoorsApr 8 – Apr 22Mar 27 – May 3
7aSow outdoorsApr 2 – Apr 16Mar 21 – Apr 28
7bSow outdoorsMar 22 – Apr 5Mar 16 – Apr 17
8aSow outdoorsMar 15 – Mar 29Mar 6 – Apr 7
8bSow outdoorsMar 3 – Mar 17Feb 21 – Apr 1
9aSow outdoorsFeb 17 – Mar 2Feb 2 – Mar 18

Growing facts

Table 3. Each value as one source states it. Sources measure differently, so values are not averaged.
FactValueSource
Frost tolerancesemi hardyColorado State1
Frost tolerancesemi hardyUtah State2
Frost tolerancesemi hardyPurdue (HO-66)3
Frost tolerancesemi hardyNebraska (G1343)4
Minimum soil temperature45°FColorado State1
Days to maturity125 days from plantingColorado State1
Days to maturity85-110 days from plantingUF/IFAS Florida5
Days to maturity75-100 days from plantingTexas A&M (E-502)6
Days to maturity90-120 days from plantingArizona (AZ1005)7
Spacing12-15 in apart each wayColorado State1
Spacing5-10 in in the row, rows 36-42 in apartUF/IFAS Florida5
Spacing10-15 in in the row, rows 30-36 in apartTexas A&M (E-502)6

Companions, and how sure anyone is

  • Tomatoes · Avoid together Extension guidance

    Shared late blight: the pathogen overwinters mainly on infected potato tubers and spreads by wind to nearby tomatoes.8899

    WSU HortSense advises against planting the two close together. The UC tradition chart also lists them as incompatible (without giving a reason); we did not find a field study of planting distance.

  • Zucchini · Avoid together Traditional pairing9

    The chart says "squash", not zucchini by name.

  • Cucumbers · Avoid together Traditional pairing9

  • Peas · Avoid together Traditional pairing9

  • Marigold · Helps Traditional pairing910

    UF/IFAS ENY-056: interplanting marigolds with nematode-susceptible crops does not control nematodes and is risky; use marigold as a cover crop 2+ months before.

  • Beans · Helps Traditional pairing9

Traditional pairings come from a UC Master Gardener chart that traces to the UC Davis Edible Landscaping Handbook and ATTRA. The chart gives no reasons, and we found no trial of these pairs; treat them as garden lore.

All potatoes companions, with sources · The full companion chart

Sources

  1. Colorado State University Extension, Vegetable Planting Guide (CMG GardenNotes #720), reviewed September 2024. Retrieved 2026-11-02.
  2. Utah State University Extension, Suggested Vegetable Planting Dates for Utah, January 2018; revised May 2025. Retrieved 2026-11-02.
  3. Purdue Extension, The Fall Vegetable Garden (HO-66-W), reviewed September 2019. Retrieved 2026-11-02.
  4. University of Nebraska–Lincoln Extension, Fall Vegetable Gardening (NebGuide G1343), Revised March 2012. Retrieved 2026-11-02.
  5. University of Florida, IFAS Extension (Department of Horticultural Sciences), Florida Vegetable Gardening Guide (SP 103 / VH021), Original December 1999; revised October 2015, January 2016, May 2018, September 2020, September 2021, and June 2025. Retrieved 2026-11-02.
  6. Texas AgriLife Extension Service, The Texas A&M System, Texas Home Vegetable Gardening Guide (E-502), 2/09. Retrieved 2026-11-02.
  7. The University of Arizona Cooperative Extension, Vegetable Planting Calendar for Maricopa County (AZ1005), reviewed This information has been reviewed by University faculty.. Retrieved 2026-11-02.
  8. Washington State University Extension (HortSense), Tomato: Late blight (HortSense fact sheet), reviewed Last review date: 2026-08-28. Retrieved 2026-11-02.
  9. University of California Agriculture and Natural Resources (UCCE Master Gardener Program), Companion Planting Chart: Companion planting in the vegetable garden, File dated 2023-09 in URL path; no date printed. Retrieved 2026-11-02.
  10. University of Florida, IFAS Extension (Entomology and Nematology Department), Marigolds (Tagetes spp.) for Nematode Management (ENY-056), reviewed Reviewed November 2019; page footer "Reviewed: 01/2024". Retrieved 2026-11-02.