How to Pollinate a Giant Pumpkin

I decided to dedicate a post specifically to pollinating a pumpkin since many of my friends and family are new to growing pumpkins, and pollinating is a very important part of growing a giant pumpkin!

To start, the pumpkin has a male and female flower. The male flower has a long stalk, and the plant is full of these flowers. The female flowers are much rarer, and they have a small pumpkin at the base of them.

These are male flowers below. It’s hard to tell because of the weeds, but they have long stalks.

This is a female flower. Note the baby pumpkin at its base.

There is a very narrow time window in which you can pollinate a female flower. Normally the female flower is closed, and it will open up one morning when it is ready to be pollinated. I usually know the time is coming the day before when the flower swells up and starts to turn from green to yellow like this:

A female flower ready to open up tomorrow morning.

When you see this, you must be prepared to pollinate the next morning if you choose to do it by hand. The other option is to let bees do the pollinating for you. Bees do a very good job at pollinating, but don’t rely on this if you are a serious pumpkin grower and want to control the genetics of your pumpkin. Also, note that bee populations have been dwindling in certain areas. I’m sad to say I’ve noticed way fewer bees at my house this year, and I’m wondering if my neighbors have used pesticides that have killed them off. If you plan on controlling your pollination, you must cover up your female flower the night before, either with a zip tie or a paper cup.

The female flower will open up in the morning, and you usually have a window between 6-10am where you can pollinate. The first thing you do to pollinate is cut off a few male flowers and peel off their petals. This will leave the stamen which contains all the pollen.

Next, I use the males like paint brushes to paint the pollen onto the female. The female flower will have a certain number of segments, each of which is connected to an ovary. Make sure to “paint” pollen on every lobe, and go gently with it.

After that, you watch and wait! When I pollinate, I put a paper cup over the flower to prevent bees from going in and spreading around different pollen. If you aren’t serious about the genetics of your next pumpkin, don’t worry about this step!