How to Grow a Giant Pumpkin

The Mythical Giant Pumpkin

New England state fairs are famous for their pumpkin competitions. Year after year, we see champion pumpkin records smashed. In 2018, a New Hampshire man named Steve Geddes grew a pumpkin that weighed 2,528 pounds and won the top prize at the Deerfield, NH, fair. It still holds the title as the largest pumpkin in North America.

Geddes also came remarkably close to the record for heaviest pumpkin in THE WORLD. The world record for largest pumpkin goes to Mathias Willemijns of Belgium, whose pumpkin weighed in at 2,624 pounds on October 9, 2016. He’s in the Guinness Book of World Records.

Can you believe this squash grew from a single seed (and maybe a lot of fertilizer)? 

Records aside, most of us are just interested in growing a healthy, large pumpkin to grace our doorstep but let’s talk about what it takes to go big.

Choose a Giant Pumpkin Variety

What’s the secret to such a massive harvest? It’s all in the seed. The pumpkin still takes between 100 and 120 days to grow, the same length of time as smaller ones. 

The seed is called ‘Dill’s Atlantic Giant’ and it will grow a pumpkin that’s generally between 200 to 300 pounds without much special attention beyond plenty of water and lots of space.

There are other types of giant pumpkin seeds, but most competition-size pumpkins come from the Atlantic Giant variety.

Order these seeds from a mail-order nursery such as Jung Seed, Park Seed, or Burpee.

Prepare the Soil Well

You need to prepare your soil in the fall before you plan to grow your giant pumpkin. Pumpkins are hungry feeders and also need a lot of space for their vines to spread out, so a giant pumpkin needs a giant amount of space. Think up to 1,200 square feet or, roughly, a 40-foot diameter circle.

1. Make sure your planting and growing area gets full sun (8 hours of sunlight per day)!
2. Till up a 10-foot diameter bed. Spread 6 inches of composted manure over the bed and till it in.
3. Shape bed into a low broad mound and cover it for the winter with a straw mulch.
   • Note: If you plan to grow more than one seed, then prepare another mound at least 10 feet apart.
4. Also, take a soil test. If your soil is acidic, apply lime in fall to bring soil to a more neutral pH.
5. In late winter or early spring, put down compost.

How to Grow a Giant Pumpkin at Home

1. As these pumpkins generally take about 120 days to mature, you’ll ideally want to get a head start by seeding seeds indoors in peat pots about a month before your average last frost date. Seeds germinate at temperatures of 65° to 75°F and soil temperatures of 70° to 90°F.
2. Once your most vigorous seedling has several leaves, transplant it into the bed that was prepared in the fall. 
3. We suggest you use a cold frame, hoop house, or high tunnel to protect the plant from late frosts and to warm up the ground, which encourages the pumpkin plant to start growing. It doesn’t have to be fancy—four stakes with clear 6-mil plastic sheeting stapled over top will do. A cold frame should cover at least a 4-foot diameter area around the young plant.
4. After you plant the seeds, fertilize every two weeks or so with decomposed manure, compost or fertilizer.
5. Pumpkins need a LOT of water. Check soil daily. The ground should ALWAYS be moist, but not soggy. Always water at the soil level, never on the leaves, which can encourage disease. Water and fertilize the soil under all the vines, not just the main root system, to encourage maximum uptake.
6. Do not let weeds grow in your pumpkin patch and be careful not to step on the ground or compact the soil near your pumpkin.
7. To put all the energy into ONE pumpkin, pick off all flower buds until the pumpkin vine is about 10 feet long. After this, let several flowers to develop into pumpkins, but remove all but the largest fruit after several weeks of growth.
8. Stake down or bury leaf nodes along the vine. These will root and help prevent wind from rolling the vines.
9. Hand-pollinate pumpkins to increase the number of seeds that develop and the likelihood for bigger fruits. To do this, pull off the petals of male flowers, which look like straight stalks, and dab these on the female flowers, which have little round ball-shaped ovaries at their base. Note that the male flowers will appear before the female flowers; be patient.
10. As the pumpkin gains size, gently slip a large piece of cardboard or piece of wood under the fruit to avoid rot and insect problems. Or, you could spread sand below the pumpkin.
11. Add a canopy of shade cloth over the chosen pumpkin. Full sun is necessary for maximum growth, but sunlight will also harden the skin of the fruit earlier, restricting its ultimate size.
12. Remove the rootlets that form along the vine for several feet on either side of the pumpkin so that the vine can lift freely from the ground as the pumpkin grows.
13. Spread a couple inches of soil over roots that form along other parts of the vines to encourage a larger root system.
14. Prune the lateral vines that develop off the main vine once they reach about 8 feet in length. Though, in general, you want as many leaves as possible to feed energy to the growing pumpkin, the plant begins to divert more energy to vine growth (rather than fruit growth) if the vines are allowed to grow to an excessive length. 
15. Harvest your pumpkin at the end of the season just before the first frost. It will appear pale yellow to orange-ish red when it is ready.

See the Almanac’s Guide to Growing Pumpkins to learn how to plant, grow, harvest, and cure pumpkins. Good luck!