How to Hand Pollinate Zucchini and Squash to Prevent End Rot, Increase Yields

Have you ever tried to grow zucchini or other squash, but much to your dismay, the promising little fruit rots and falls off instead of growing to mature size? The squash flower mostly likely didn’t get pollinated, but it’s really easy to do yourself! This quick tutorial will show you exactly how to hand pollinate zucchini and other types of squash to prevent end rot and increase yields. I’ve also addressed some frequently asked questions, and included a demonstration video.

These tips apply to hand pollinating summer squash (e.g. zucchini, patty pan, or crookneck squash) as well as winter squash like butternut, pumpkins, or acorn squash. As fellow members of the cucurbit family, you can use the same method to hand pollinate cucumbers and melons too!

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RELATED: Pop over to our guide on how to grow zucchini and summer squash for even more tips, and don’t miss these 13 excellent ways to use zucchini – including recipes for fresh eating and preserving. Our sourdough zucchini bread recipe is one of my favorites!

What happens when zucchini flowers aren’t pollinated?

When a female squash flower doesn’t get pollinated, the small attached fruit will fail to develop. It will stay stunted, start to rot from the flower end, and eventually die and fall off. Therefore, if you want to ensure your plants produce plenty of edible squash for you to enjoy, hand pollinating zucchini can vastly increase their success – and your yields!

If your garden has a healthy bee population, they may pollinate the flowers for you. Yet even here in our garden, which is bursting with pollinator plants and buzzing with bees, we still find that some squash develop end rot due to lack of pollination on occasion! So I still routinely hand-pollinate. Why not guarantee success?

Male vs Female Zucchini Flowers

In order to hand pollinate squash, you’ll need to be able to identify the difference between the male and female flowers. Both play an important role in pollination and fruit development!

A female zucchini flower is most easily identified by the little immature squash fruit attached at the base of the flower. For other types of cucurbits, you’ll see the same thing: a tiny butternut squash, tiny cucumber, or tiny melon at the base of the female flower. Additionally, if you peek inside the flower, the inner bits are more round and curvaceous. That’s called the stigma.

On the contrary, a male zucchini flower has a plain straight stem at the base of the flower rather than a small fruit. Inside is the anther: a straight appendage with a pollen-covered tip. See the images below.

How to Hand Pollinate Squash

To hand pollinate zucchini and squash, first identify both an open male and female flower. Then simply transfer pollen from the male flower’s anther onto the female flower’s stigma. It’s so easy to do, and just a small amount of pollen will do the job! Here are a few different methods you can use to transfer pollen from the male to female blossom:

• Some folks remove the male flower from the plant, peel back its petals, and rub the pollen-covered anther directly on the female flower’s stigma. I personally don’t love this method; I prefer to leave the blossom in place for the bees, or for later pollination use!
  
  
• Others gardeners use a Q-tip for hand pollination. In my experience, a lot of the pollen sticks to the Q-tip itself, leading to less pollen transferring from flower to flower.
  
  
• My favorite way to hand pollinate squash is with a dainty paint brush. Use the paint brush to collect some pollen from the male, spread some onto the female stigma (or many ladies), and it’s done! Using a paintbrush is really effective, but also feels fun and fancy. I leave my pollination paint brush out in the garden during squash season.
  
  
• Each female flower only needs to be pollinated one time.
  
  
• Don’t have a male and female flower open at the same time? Keep reading for more tips below.
  

When to Hand Pollinate Squash

It’s best to hand pollinate zucchini and squash flowers as soon as they open (the same day if possible).

I’ve found that most squash blossoms open in the morning and close up by the evening, so checking daily is important if you want to pollinate them all. However, sometimes they can open at various times of day, so morning isn’t necessarily a steadfast guarantee.

If you miss the initial bloom – don’t fret! You can carefully peel open the flowers (once they have already opened and closed) to access their insides for a couple days after if needed. This goes for both males and female flowers, which is just one more reason to not pick off the males.

What if I only have male or female zucchini flowers?

Some gardeners get frustrated because their plants produce only male flowers, or only female flowers, but not both at the same time. Don’t worry. It’s not uncommon for squash plants to produce one or the other more heavily early in the season. They should naturally even out as the plant matures, usually within a few weeks.

Very hot weather can also make zucchini plants produce more male flowers. It may be worthwhile to protect your plants with shade cloth during prolonged heat over 95°F. We always grow several squash plants to help ensure there will be a good mix of male and female flowers open around the same time.

Can I use different squash varieties to hand pollinate each other?

Absolutely. While it’s ideal to use similar varieties when possible, you can also use the pollen from different varieties of squash to hand-pollinate others when needed. Bees don’t discriminate and will naturally cross-pollinate between your plants after all! The squash will develop just fine.

However, for the best fruit development, try to stick to the same general family by keeping summer squash and winter squash separate. For instance, use the male flower of a yellow crookneck squash to pollinate a green zucchini female, or a butternut squash to pollinate a pumpkin.

After cross-pollination, you won’t be able to save seeds from those fruit since the next generation will not “breed true” to the parent plant variety. Again, this would likely be the case with natural bee pollination between varieties in your garden anyway.

Demonstration Video

Don’t mind my sense of humor!

That concludes this lesson on hand pollination.

Now go have fun diddlin’ some squash of your own! I hope you found this helpful, and that you’re blessed with plenty of healthy zucchini this summer. Please feel free to ask any questions, and spread the love by sharing or reviewing this post.

If you find yourself with some large overgrown squash, you should try our Fiesta-Style Stuffed Squash recipe! Loaded with wild rice, black beans, veggies, flavor, and protein… you can’t go wrong. Or check out the other zucchini recipes below:

• Delicious Sourdough Zucchini Bread Recipe (Optional Walnuts or Chocolate) 
• 13 Must-Try Zucchini Recipes: Clever Ways to Use Zucchini
• Easy Parmesan Zucchini Fritters Recipe (Healthy Yogurt Dill Sauce)
• How to Freeze Zucchini (Summer Squash) Two Ways

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How to Hand Pollinate Zucchini and Squash (Prevent End Rot, Increase Yields)

Learn how to hand pollinate zucchini to prevent end rot and increase yields, including how to tell the difference between male vs female zucchini flowers. These tips apply to all types of summer squash (zucchini, crookneck, yellow, etc), winter squash (like butternut and pumpkins) as well as melons and cucumbers!

Active Time3 minutes mins

Keyword: hand pollinate squash, hand pollinate zucchini

Equipment

• squash plants
• small paint brush or q-tip (optional)

Instructions

• First identify both an open male and female flower. See tips in the notes below if you don't have both types open a the same time.
  
• A female zucchini flower has an immature squash fruit attached at the base of the flower. Additionally, there is a bulbous, curvaceous stigma inside the flower.
  
• A male zucchini flower has a plain straight stem at the base of the flower rather than a small fruit. Inside is the anther: a straight appendage with a pollen-covered tip.
  
• Next, transfer pollen from the inside of the male flower to the inside of the female flower. We like to use a small paint brush to collect and transfer the pollen. Other options include a q-tip, or plucking the male flower off the plant, peel back the petals, and rub it directly inside the female.
  
• It's best to hand-pollinate squash the first time the flower opens (often in the morning) so check your plants daily!
• You can use flowers from different plants or even different varieties of squash to hand-pollinate one another if needed.
• Each flower only needs to be pollinated one time, and now a squash will develop as expected.

Notes

If there isn’t a male and female flower open at the same time, you can gently peel open flowers that have already bloomed and closed again (within a couple days of blooming) to access their insides for pollination. Growing at least two squash plants will also help increase pollination odds and flower availability.