Although the quintessential pumpkin that first comes to mind for most of us is of the perfectly round, orange variety, there are so many different types of pumpkins you can grow right in your backyard! Regardless of what pumpkin you pick, watching them grow is a true treat, especially when the first tiny one starts to take shape. And if you're anything like us, you'll want to ensure these fall fruits live long and healthy lives! Learning how to prevent pumpkin rot will significantly extend their lifespan from growth through harvest and beyond.
"There are several reasons why pumpkins rot," explains Nate Gorlin-Crenshaw, trial technicians for pumpkins and winter squash with Johnny's Selected Seeds. "Disease, environmental conditions, and pests that introduce damage to the fruit are the most common issues." While that might sound bleak, all is not lost! There are a handful of ways to save your pumpkins from these factors that can cause this damage. Ahead, we'll walk you through the best ways to grow your pumpkins in order to prevent them from rotting.
How do I keep my pumpkins from rotting on the vine?
One reason your pumpkin might start to rot is from powdery mildew. "This a fungus that looks like it sounds," says Gorlin-Crenshaw. "It's a whitish, powdery substance that appears on leaves first, then spreads to the vines and stem." First, try and select varieties that are disease-resistant, which will be listed on the seed label or plant tag. Older heirloom types, such as Howden, tend to be more susceptible. Newer types, such as Gumdrop and Pipsqueak, are more resistant.
Obviously, it’s too late for that step if you’ve already planted, but there are other preventative measures you can take. The disease generally appears in mid to late summer. A few weeks beforehand, start applying a preventive spray containing potassium bicarbonate, copper, or sulfur, and follow the label instructions exactly. Basically by doing this, you're stalling the disease so the pumpkin has time to produce fruit before the fungus kills the plant. "Prevention is way more effective than treating, because you won’t stop it once it starts," says Gorlin-Crenshaw.
You'll also want to watch out for black rot. Also called gummy stem blight, this disease is as nasty as it sounds. The fruit gets a big, black bruise and rots quickly. By the time you see it, it’s already too late to save the plant. You should also avoid planting pumpkins in this same area again next year because it's primarily a soilborne fungus. The pumpkin is also more vulnerable if insect pests have damaged the fruit.
How do I protect my pumpkins from disease?
The yellow and black-striped cucumber beetle, which is about the size of half a lentil, is the culprit for introducing a common pumpkin disease known as bacterial wilt. This disease affects the plant more than the fruit. You may see the beetles crawling around, or they may swarm up around the plant. They chew on the tender new growth, fruit and flowers, and their saliva carries the disease. And yes, the leaves will look wilted.
You can protect plants with floating row covers when they're newly transplanted. However, once flowers appear, you'll need to remove them so the flowers can be pollinated in order to set fruit, says Gorlin-Crenshaw. If you spot these bugs, the best control is a contact insecticide. Apply an organic insecticide early in the morning or late evening before or after pollinators are active for the day so you won't hurt them. Look for products containing neem oil, azadirachtin, or pyrethrin, and always follow the label instructions.
Sometimes you can prevent rot with environmental controls, such as gently lifting pumpkins off the soil when they're small and placing them on a clay pot, straw, mulch, or a piece of landscape fabric. "You're creating a barrier between the fruit and the soil to prevent disease or keep them from getting too wet," says Gorlin-Crenshaw.
When is the best time to pick pumpkins to avoid rot?
If you wait too long to harvest, you might end up with a mushy pumpkin. Pick your pumpkin when you like its appearance, and it's nearly to the color for the specific variety. The plant should be starting to brown and die back. It's okay to pick when your pumpkin is a little green if it's an orange pumpkin as it usually keeps developing some color. But don't wait to pick until after a frost or its shelf life is reduced significantly, warns Gorlin-Crenshaw.
How to prevent uncarved pumpkins from rotting?
Once you’ve harvested your pumpkin, rinse it clean. Many people also swear by a mild bleach wash, which may (or may not!) extend your pumpkin's lifespan by preventing microbes. Mostly, you'll want to keep it out of freezing temperatures or direct sunlight in order to make it last longer. You can try the bleach solution with carved pumpkins too, but basically, once you cut up your pumpkin, it will only last a few days.
How to prevent carved pumpkins from rotting?
Similar to the preventative measures for uncarved pumpkins, washing the outside and inside of your pumpkin with the bleach solution can help remove decay-causing microbes. Use the mild bleach wash both before and after carving, making sure to remove any traces of pulp from the pumpkin. As with many fruits, keeping your carved pumpkin cool and out of direct sunlight can also help to slow its decay. Another helpful hack is to line the carved edges of your pumpkin with petroleum jelly to prevent moisture loss and shriveling. Using battery-operated lights rather than a real candle to light your jack-o-lantern is also recommended, as the warmth from the candle can speed up the rotting process. Afterwards, bring everything full circle by tossing your rotting pumpkin into the compost pile!
Everything You Need to Keep Pumpkins from Rotting
Pipsqueak Pumpkin Seeds
Floating Row Plant Covers
Copper Fungicide
Bonide Neem Oil Insect Pesticide for Organic Gardening
Arricca Elin SanSone is a writer, editor, and content creator who specializes in lifestyle and gardening. With a background in health reporting, she applies these same research skills when writing about the science of growing things. She trials new plants in her expansive garden, and her houseplant collection consists of 60+ varieties. Arricca has written thousands of articles for publications such as Country Living, House Beautiful, Good Housekeeping, Prevention, VERANDA, Southern Living, and more. She’s happiest when digging in the dirt, baking, or spending time with the people and dogs she loves.
