Pollination Vegetables

My Squash Plants Only Produce Male Flowers

Squash plant with male flower. Photo: extension.unh.edu

Question: I think something is wrong with my squash plants. They produce only male flowers. 

C. Carmichael

Answer: Just be patient: the female flowers will come.

Squash such as zucchinis and pumpkins, as well as most other cucurbits (cucumbers, melons, watermelons, etc.), produce unisexual flowers—separate male and female flowers—on the same plant. 

Male flower on the left, female, with its swollen ovary, on the right. Photo: http://www.missouribotanicalgarden.org

The two can be readily told apart by ovary in the form of the future fruit (round, long, crookneck, etc.) found at the base of female flowers. Only female flowers. The males have no ovary and produce, of course, no fruit, but are vital as they provide the pollen needed by the female flowers to produce fruit.

Ma Nature produces male flowers first to start to attract pollinators. Producing male flowers requires little energy and they are produced abundantly. Each lasts but a day, but new ones replace them. So, after a few weeks of male-only flowers, pollinating insects such as bees will hopefully have become accustomed to visiting the flowers daily to pick up pollen and nectar. That way, when the first female flowers appear, there’ll be bees ready to pollinate them. 

So … just wait. The female flowers are on their way!

In the Absence of Pollinators

But what if you’re not seeing bees visiting your squash flowers? First, you do have to look in the morning: squash flowers are pretty much morning bloomers. And adverse weather—heavy rain, extreme heat, unusual cold, etc.—can keep bees away. Also, don’t water on mornings when the plant has female flowers … or if you do water, water only the soil, not the blooms. With that female flower only opening for one day, you do not want to discourage pollinators on that one occasion! 

These improperly pollinated fruits were aborted. Photo: J. Allen, uconnladybug.wordpress.com

It takes up to 12 bee visits to properly pollinate a squash flower. If bees are not visiting regularly, you have a problem, as improperly pollinated fruits will abort and drop off.

Hand pollination may be necessary. Photo: sendjoelletter

That’s why hand pollination is useful and may even be necessary. In fact, many gardeners find they obtain earlier and more numerous fruits when they hand pollinate, largely because that way, more pollen is applied and therefore fewer fruits abort. Read Be Like a Bee and Pollinate Your Curcubits to learn how to hand pollinate your squash flowers. 

Larry Hodgson is one of Canada’s best-known garden communicators. After studies at the University of Toronto and Laval University where he obtained his B.A. in modern languages in 1978, he succeeded in combining his language skills with his passion for gardening in a novel career as a garden writer and lecturer. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He is a regular contributor to and horticultural consultant for Fleurs, Plantes, Jardins garden magazine and has written for many other garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening, Rebecca’s Garden and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 50 other titles in English and French. He can be seen in Quebec on French-language television and was notably a regular collaborator for 7 years on the TV shows Fleurs et Jardins and Salut Bonjour Weekend. He is the President of the Garden Writers Association Foundation and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. An avid proponent of garden tourism, he has lead garden tours throughout Canada and to the gardens of over 30 countries over the last 30 years. He presently resides in Quebec City, Quebec.

5 comments on “My Squash Plants Only Produce Male Flowers

  1. I’ve got winter squash, and I’ve got blooms. So, I’ll be checking this out this morning. Thank you.

  2. Thank you, you answered my question about the male flowers. I know I didn’t ask it but jt was in my head.

  3. Mine seemed to start producing female flowers first. The fruits seemed to start to develop before the flowers opened.

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