How to hand pollinate pumpkin flowers

This short post is part show and part tell, and it briefly covers:

1. What male and female pumpkin flowers look like.
2. How and why to hand pollinate your pumpkin flowers.
3. Protecting pollinated flowers from rain.
4. Thoughts about where to put your pumpkin patch.

Male and Female flowers on the same plant

Pumpkins and other Cucurbits (like zucchini, squash, gourds, cantaloupes) have separate male and female flowers on the same plant.

In order for a female flower to produce a fruit, it needs to be pollinated with pollen from the male flower. Pollinating insects will obviously do this for you, but in rainy weather or if you have a shortage of pollinators, hand pollination is a simple and easy solution. (Although I also encourage you to consider how you can support your pollinator insect populations as much as possible!)

Telling females from males

Some years ago our friends’ young children were visiting to play with our young children and my friend later told me that her daughter had come home and said, “Mummy, I know how to tell boys from girls.”

“Really? What kind of boys and girls?”

“Pumpkin flower ones!”

Most homegrown food and medicine is so simple a small child can do it, and this is certainly the case with pollinating pumpkins. In the image up the top you can see the swelling at the base of the female flower on the right. In the image below, you can see the multiple headed stigma in the center of the female flower on the left and the single stamen in the male flower on the right.

As another friend said when I was first learning about this, “it’s pretty obvious which is male and which is female.

Hand pollinating

So the next question is what do you do with these male and female flowers?

In a perfect world all you’d have to do is sit back and admire them, and feel gratitude for and wonder about the pollinating insects busily carrying pollen about with them. But in wet weather (which for obvious reasons reduces insect activity), or if you have a shortage of pollinators due to indescriminate pesticide use and upsets/imbalances in your garden and surrounding ecosystem, you might want to lend a hand.

In the picture below you can see the male flower removed from the plant, and then in the next picture with its stamen separated from its petals.

(You can eat the petals of the male flower while you do your pollinating, or bring them in and put them in a salad. Or if you don’t want to destroy the male flower, collect some of its pollen with a cotton wool bud or a paint brush. If you go this route, keep whatever tool you use for transferring pollen in a clean dry place so you can use it over and over again.)

Whether with the broken off male stamen or with a cotton wool bud or paintbrush, transfer some pollen to the multiple headed stigma in the centre of the female flower. You’ll see the powdery pollen on the male stamen and if you look closely you can see some of it transfer to the female flower.  Be thorough: brush a little pollen onto each of those little curving female parts.

Below, you can see a pumpkin forming from a successfully pollinated flower on the left, and one that missed out on the right.  The petals of the flower that was not pollinated had already fallen, and the browned off swelling from its base also fell when I brushed against it. Watch out for these browned off female flower swellings – they’re a sure indicator of inadequate pollination in your pumpkin patch.

Making a hat

We live in an area that can be very wet, so after hand pollinating, to prevent the newly pollinated female flowers from filling with rain and possibly failing to set fruit, sometimes I give them a hat.

In the picture below I’ve broken off a large leaf and…

positioned it over the female flower as a rain hat,

and brought its stem together with the stem of a leaf above to make it less likely to fall or blow away. (Same leaves. Sorry about the change in colour from the last picture to the one below… the sun must have come out or something. Photography isn’t one of my strengths.)

A decent breeze would mess up my nice architecture of course, but it only needs to stay put for a day or so.

When do female flowers open, and for how long?

Pumpkin flowers begin to appear when the vine is about 50-55 days old. The male flowers start opening about a week before the female ones, so if at first you see only males, don’t panic — the girls will be along soon. There are always more male flowers than female, and the female flower opens in the morning and will close by afternoon or evening.

So it’s worth paying a visit to your patch every morning to pollinate open female flowers and take note of where new ones are forming. In the picture below, I’ve circled immature female flowers in yellow and males in orange.

Where to put the pumpkin patch?

This question becomes relevant when you think about how you’re going to make sure that daily hand-pollinating happens in your pumpkin patch. It’s a quick, easy task, but it’s also easy to forget to do.

I used to think of pumpkin vines as plants that belonged in a out of the way spot where they could be comfortably messy and no-one would see the mess. Now, I keep our messy pumpkin patch right beside our most used path, within easy view of the porch – because that way I see the flowers each morning and they remind me to go out to the patch to pollinate.

Those brief pollinating moments usually lead to further moments out in the garden that I might otherwise not have indulged in – and all of that is good for the soul and also for the kitchen table.

Byline

Kate writes at ARealGreenLife.com about making healthier choices for ourselves and for our families, communities, and ecosystems.