When to Plant Pumpkins

The two rules

Pumpkin timing comes down to two limits. The early limit is cold: pumpkins are among the most frost-tender crops in the garden, and Colorado State plants them two or more weeks after the average last frost. Clemson wants soil at least 60°F at 4 inches deep, and Utah State plants at 65°F. A soil thermometer in mid-morning is the best guide; the dates for your zone above show when that warmth usually arrives.

The late limit is the fall freeze. A pumpkin needs its full season to mature, and while a light frost only kills the vines, a hard freeze damages the fruit. Most varieties take 90 to 120 days from seed. UF/IFAS gives 80 to 100 days from seed and 70 to 90 from transplants, and Clemson lists ‘Big Max’ at 120 days and ‘Big Moon’ at 115.

Counting back from Halloween

To have pumpkins ready for October:

1. Find the days to maturity on the seed packet.
2. Pick a target harvest date, such as late September or the first week of October.
3. Count back that many days, then add a week or two because cool fall weather slows ripening (Iowa State).
4. Check that this date falls after your safe spring planting date and that the harvest falls before your average first fall frost.

A 100-day variety aimed at October 1, for example, counts back to about June 20; with the cool-weather margin, sow it in early to mid-June, and earlier is safer in the North. Large-fruited and giant types need the long end of that range, while miniatures such as ‘Jack Be Little’ finish sooner.

Planting a bit early is a smaller risk than planting late. Cured pumpkins stored at 50 to 55°F keep about 2 to 3 months, so a September harvest still lasts to Halloween and Thanksgiving.

The North and Midwest

In the northern half of the country, the spring and Halloween limits overlap neatly, so pumpkins go in as soon as the soil is warm. Iowa State sows in mid-May in central Iowa, 7 to 10 days earlier in the southern part of the state and 7 to 10 days later in the north, with mid-June as the last practical date. Colorado State notes that pumpkins do best below 5,000 feet; above that, the warm season is often too short for them.

Short-season gardeners can gain time two ways. Starting seed indoors 3 to 4 weeks ahead in peat pots or other plantable containers gives a head start (Iowa State). Black plastic mulch with row covers lets you plant about two weeks before the last frost date, according to Utah State. Take covers off when flowers open so bees can pollinate.

The Southeast

In the South, the season is long enough that timing is set by the harvest date rather than the frost date. Clemson plants pumpkins only for a fall crop: June 15 to July 15 in the South Carolina Piedmont, and June 1 to 30 in the Coastal Plain. Powdery and downy mildew are among the diseases Clemson lists for pumpkins, so varieties with some resistance help, such as ‘Big Max’ and ‘Big Moon’, which Clemson describes as partially resistant to downy mildew.

The desert Southwest

In the low desert around Phoenix, the University of Arizona gives two windows: sow in March for an early summer crop, or from July to early August for a fall harvest. The second window is the one for Halloween.

Florida and other warm-winter areas

UF/IFAS schedules pumpkins as a single summer planting for fall harvest: early July in North Florida, mid-July in Central Florida and early August in South Florida. For gardeners in zones 10 and 11, that late-summer sowing is the only window, and the tropical pumpkins calabaza and Seminole, which UF/IFAS describes as disease resistant, are a better fit than northern jack-o’-lantern types.