Big Max, Medium Results: Growing Giant Pumpkins at 7,200 Feet

Big Max is sold on the promise of a 100-pound pumpkin. On the Palmer Divide, where the average low tops 50 degrees only in July and August and severe hail peaks in June, a 60-pounder is a good year’s work.

The seed company is not modest. Big Max, according to Botanical Interests, a Broomfield firm that sells it, can reach 20 inches across and 100 pounds or more, and has “smooth, light-orange skin.” The largest in your correspondent’s garden this year is close to 60 pounds, by estimate rather than by scale. It is the color of smoked salmon, with cream stripes down its ribs. Another, pollinated late, is still lemon yellow.

The shortfall is the altitude’s doing. Colorado State University Extension says pumpkins and winter squash “require a long, warm growing season and are most productive at elevations below 5,000 feet.” The garden in question, in a suburban neighborhood on the Palmer Divide, sits at 7,200. Cold nights, a short season and summer hail each take a share of the pumpkin. What is left is still a big pumpkin, and with some help it can be a bigger one.

Cold nights, short season

Pumpkins like warm nights. Penn State Extension’s guide for growers puts their best range at 65 to 95 degrees Fahrenheit and says temperatures below 50 “slow growth and maturity of the crop.” At NOAA’s weather station in Monument, 7,080 feet up, the average low clears 50 degrees in two months of the year, according to NOAA’s 1991–2020 climate normals: July, at 53.7, and August, at 51.5. June averages 47.2 and September 43.5.

The season is short at both ends. At the same station the median date of the last spring freeze is May 14 and of the first fall freeze Oct. 1, by the Colorado Climate Center’s reading of the same normals. That leaves 140 days between them in a typical year, and one year in ten the first freeze arrives by Sept. 16. Big Max needs 120 days from seed by most seed companies’ count, and 100 by Urban Farmer’s. Sown promptly in late May, it can just make it.

The hail, and a late start

Then there is hail. In El Paso County, reports of severe hail, an inch across or larger, peak in June, and August sees about half as many, according to figures from Russ Schumacher, the state climatologist, and a graduate student, published by KOAA in 2019. Last summer the vines in your correspondent’s patch were destroyed four times. Each time they grew back, and they still set fruit. CSU’s PlantTalk service, which advises gardeners on what to do after a hailstorm, puts the matter simply: “plants want to grow.”

So this year the seeds went into the ground on July 1, about a month later than usual, in the hope that the plants would come up after the worst of it. No hail fell on the patch all summer. Whether the plan worked or the weather took the year off, a sample of one garden cannot say.

The late start had a price, and it is printed on the calendar. From July 1 to Monument’s median first freeze is 92 days, short of the 100 to 120 the seed companies ask for. (Penn State’s guide says pumpkins in Pennsylvania are “generally seeded in the field during the first couple weeks of July.” By that standard the planting was right on time.)

A different shade of orange

Nor does the crop look much like the pumpkins stacked outside a grocery store. Carving pumpkins are sold on their looks: Johnny’s Selected Seeds describes its Early Giant as “medium-dark orange” and “uniform in shape.” Big Max belongs to a different species, Cucurbita maxima, the same one as Atlantic Giant, which Johnny’s describes as “pale orange with a pink tinge.”

Botanical Interests’ own description of Big Max takes care to say that, “unlike some large pumpkins that are just blobs,” it is round. A customer review on the same page is briefer: “Not the prettiest of pumpkins, but fun.” Your correspondent’s crop runs from salmon to a late arrival that is still lemon yellow, with one nearly regulation orange, striped in yellow, as though it had read the catalog.

Helping them along

Most of what helps a pumpkin at altitude comes down to warmth, water and food. The advice below comes from extension services and seed companies; the compost and the pumpkin fertilizer are your correspondent’s own habits.

Start indoors. Pumpkins resent having their roots disturbed, so CSU says the only practical transplant is one started in its own pot. Johnny’s growing guide suggests sowing about three weeks before planting out, and says to subtract 14 days from a variety’s days to maturity when counting from the transplant date. In a 140-day season, two weeks is a lot.

Warm the soil. Black plastic mulch warms soil 8 to 12 degrees above bare ground, according to Penn State. Fabric row covers keep the chill off young plants, but Johnny’s says to take them off once the plants begin to flower. The flowers depend on insects, mainly bees, for pollination, CSU notes.

Plant on a mound. CSU’s fact sheet calls for hills, so that water drains away from the seedlings: five or six seeds to a hill, hills four to six feet apart, thinned to the two or three strongest plants. Clip the extras rather than pulling them, so the roots of the keepers are left alone.

Feed them, but go easy on nitrogen. CSU suggests working a pound of nitrogen per 1,000 square feet into the soil before planting, or, for organic growers, two bushels of manure per 100 square feet. Its pumpkin advice adds more fertilizer along the rows once the vines start to spread. Your correspondent side-dresses with compost and a fertilizer sold for pumpkins. Urban Farmer warns that too much nitrogen buys leaves at the expense of flowers and fruit.

Water deeply, not daily. Once the vines cover the ground in warm weather, CSU says, they can use an inch to an inch and a half of water a week, better given every five to seven days than sprinkled every day. Wilting in the afternoon heat is common; wilting in the morning is “a distress signal.” Water at the roots and not in the evening, since damp leaves invite powdery mildew, which CSU calls the most common leaf disease of squash, cucumbers and melons.

Keep one pumpkin per vine. For size, Botanical Interests advises leaving a single fruit on each Big Max vine. Johnny’s says the same practice, with irrigation and 70 or more square feet per plant, turns Atlantic Giants that would commonly reach 50 to 100 pounds into 200- to 300-pounders.

Plan for hail. South Dakota State University Extension suggests hail netting or shade netting over sturdy supports, since hail usually comes with strong wind, and says a tarp or an old blanket thrown over the plants is better than nothing. After a storm it advises removing stems that have broken off but leaving torn leaves in place until new growth appears, because the plant still needs them to make food.

Watch October. Johnny’s says pumpkins can take a light frost or two but that temperatures below 28 degrees can damage the fruit. Monument’s median date for its first 28-degree night is Oct. 10. A pumpkin is ready when its rind resists a thumbnail, CSU says. The seed companies advise cutting it with several inches of stem and curing it in the sun for five to seven days, or indoors at 80 to 85 degrees.

Freeze dates and temperatures: NOAA 1991–2020 climate normals for the Monument station, via NOAA and the Colorado Climate Center. Growing figures: Colorado State University Extension and the seed companies named above.

Other pumpkins worth a try

Big Max is one choice among many. Eight others are below, with what each offers a high-altitude garden, starting with the two CSU itself suggests. Days are counted from seeding, and days and weights are the seed companies’ own figures; most of these are sold by other companies too. The chart shows the latest date each can be sown and still ripen before Monument’s median first freeze.

Sources: CSU PlantTalk for the two CSU picks; each variety’s page at Botanical Interests (Howden) or Johnny’s Selected Seeds (the rest). Days to maturity are from direct seeding; Johnny’s says to subtract 14 for transplants.

Before Halloween

One more risk belongs to this year in particular. Colorado Parks and Wildlife, in a year it says has brought historic levels of conflict between people and bears, asked on Oct. 2 that pumpkins not be left outside overnight, even before they are carved. Bears fattening up for winter are eating as many as 20,000 calories a day, it says, and pumpkins are “a high-calorie treat.” The Independent has reported on this summer’s bears in Palmer Lake. Your correspondent’s pumpkins have spent every night outdoors since July. They are, in fairness, still attached to the vine.

For readers who would rather buy than grow, the Independent’s Tri-Lakes Halloween Guide lists three pumpkin patches open in October, along with every trunk-or-treat it can verify. At Colorado Kids Ranch’s patch on Highway 105, pumpkins cost $4 to $12, depending on size, on top of admission of $18 to $20. Set against a summer of compost, fertilizer and water, that may be a bargain. Your correspondent has not done the math.

Sources & further reading

The Independent’s own coverage: The Tri-Lakes Halloween Guide, for pumpkin patches and trunk-or-treats · Bears, Trash and a Town Hall, on this summer’s bear conflicts in Palmer Lake

Climate: NOAA 1991–2020 monthly normals, Monument station (data file) · Colorado Climate Center, frost and freeze dates by station · Colorado Climate Center, “First fall freezes” · KOAA, “Statistically, Colorado’s severe hail season is winding down” (Aug. 7, 2019)

Growing advice: CSU Extension, Cucumbers, Pumpkins, Squash, and Melons · CSU PlantTalk, Growing Great Pumpkins · CSU PlantTalk, Hail Damage · Penn State Extension, Pumpkin Production · Johnny’s Selected Seeds, Pumpkins: Key Growing Information · SDSU Extension, Preventing and Dealing with Hail Damage in the Garden · El Paso County Extension, Landscape and Garden Help Desk

Seed catalogs: Botanical Interests, Big Max · Botanical Interests, Howden · Urban Farmer, Big Max · True Leaf Market, Big Max · Johnny’s, Baby Bear

Photographs of other varieties: KENPEI, Atlantic Giant (CC BY-SA 3.0) · U.S. Department of Agriculture, Jarrahdale (public domain) · Badagnani, Long Island Cheese (CC BY-SA 3.0), all via Wikimedia Commons

Wildlife and pumpkin patches: Colorado Parks and Wildlife, “Keep wildlife in mind when placing pumpkins this season” (Oct. 2, 2026) · Colorado Kids Ranch, Plan Your Visit

Methodology

Temperatures and freeze dates are NOAA’s 1991–2020 climate normals for its Monument station (USC00055734, elevation 7,080 feet), read from NOAA’s monthly normals file and from the station table behind the Colorado Climate Center’s freeze-date map. A freeze is a low of 32 degrees or colder. The dates are medians, so in half of years the event comes earlier. The 140-day and 92-day figures are the Independent’s count of days between those dates. In the chart, each variety’s latest sowing date is the Oct. 1 median minus its days to maturity as the seed company states them; seed companies count days differently, so treat the dates as a guide, not a deadline. One station does not describe every yard; a garden higher up or in a cold hollow may freeze sooner. The 7,200-foot elevation is the garden’s own, and the 60-pound weight is an estimate: the pumpkin has not been weighed.

Using this reporting? Credit The Monument Independent and link to this article: https://monumentindependent.com/news/big-max-pumpkins-palmer-divide/. Our guidelines are at Using Our Reporting.