By Tom Kalb, Horticulturist

NDSU Extension

It’s fun to grow your own Halloween pumpkins.

Bigger is often better, but I don’t want to grow a giant, 300-pound pumpkin. Those pumpkins are lopsided. They are ugly. They look more tan than orange in color. Their vines gobble up the entire garden.

Giant pumpkins require a lot of work. You have to start the seeds indoors. You have to feed and water the vine constantly all summer. You have to put a blanket on the fruit so its skin stays soft and keeps expanding. The fruit is so needy that it is almost like having another pet.

That is too much work for me. Plus, what do you do with a 300-pound pumpkin? You can’t even get it out of the garden without a tractor.

There are better options, and this is one focus of NDSU Extension’s North Dakota Home Garden Trials this summer.

We are testing easy-to-grow, big (not giant), beautiful pumpkins. Most of these varieties will grow pumpkins that weigh 40 pounds, some heavier. The fruits are uniform in shape, bright orange in color and have strong handles. Their vines are productive and resist diseases.

Some of these varieties like Big Moose, Captain Jack, Early Giant and Large Marge have done well in previous tests. Other varieties like Big Doris and Denali have rarely if ever been grown in our state before. You are welcome to test them yourself by participating in our program. Our website is ndsu.ag/homegardentrials.

At garden centers, the biggest pumpkin varieties you are likely to find are Atlantic Giant and Big Max. These varieties will produce big pumpkins, but their vines are not as productive or disease resistant as most hybrids. Atlantic Giant fruits are the largest, but are misshapen and unattractive.   

No matter what variety you select, pumpkin seeds may be started indoors. Start them in early May and transplant the seedlings in late May. Seeds will germinate best under warm (80 degrees Fahrenheit) temperatures.

I don’t sow my seeds indoors, choosing instead to sow early ripening varieties directly in the garden. In late May, I sow two seeds every 36 to 72 inches in rows spaced 10 to 12 feet apart. The larger the space, the larger the pumpkins will be. If both seeds germinate, thin out the weakest one.

My pumpkin plants do not receive special care. I deeply irrigate my garden once and no more than twice a week. I sidedress the plants with fertilizer once in summer. For bigger pumpkins, you can water and sidedress the vines more often.

It is important to avoid overhead sprinkling. Wet leaves, especially during the evening, create humidity that powdery mildew and other diseases thrive in. These diseases will weaken the vines particularly late in the summer when the fruits need energy to grow.

That’s why I always sow modern, F1 hybrid pumpkins that resist powdery mildew. In contrast, most non-hybrids are very susceptible to diseases.

For bigger pumpkins, you can thin the fruits down to one or two per vine. I don’t bother doing that, but I will remove any pumpkin fruits that are set after mid-August. These late fruits will not ripen before frost and will rob energy from the other fruits.

I can’t wait to grow pumpkins with my kids this summer. The expressions on their faces when they see the big, beautiful fruits will be priceless.   

For more information about gardening, contact your local NDSU Extension agent. Find the Extension office for your county at ndsu.ag/countyoffice.  

NDSU Agriculture Communication – April 23, 2025

Source: Tom Kalb, 701-877-2585, tom.kalb@ndsu.edu

Editor: Kelli Anderson, 701-231-6136, kelli.c.anderson@ndsu.edu