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
How to Hand Pollinate Zucchini and Squash (Prevent End Rot, Increase Yields)
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
Deanna Talerico
Deanna Talerico (aka DeannaCat) is a garden educator and writer with over 15 years experience in organic gardening. She is a retired Senior Environmental Health Specialist, and holds a M.A. in Environmental Studies and B.S. in Sustainability and Natural Resources.
68 Comments
Gene @The California Table
wondering about promoting more flowers (and thus, more fruit) at the same time as we hand pollinate? Usually plants will produce new blooms if gardeners remove spent flowers right away (deadheading); a response to the plants’ drive to reproduce.
so, I wonder whether breaking off male blooms to hand pollinate the female flowers would provoke the plant into producing more flowers?
Plus, I like to EAT squash flowers and usually focus on picking male blossoms for eating. I bet you all at Homestead and Chill also cook with squash flowers 🙂
Have you experimented with this or do you know of any evidence that breaking off male flowers encourages productivity?
Thank you!
Aaron (Mr. DeannaCat)
That’s an interesting point about deadheading flowers but I am not sure that it necessarily promotes more flowers although plucking male flowers likely allows the plant to focus on fruit development. If you do hand pollinate the female flowers, you may as well pick the male flowers after they are of use to you, you may miss out on a few extra fruit this way but our plants usually supply us with more than enough squash. Let us know how the season goes for you and enjoy those squash blossoms!
Aaron Cayton
Thank you for the info! I learn a lot from your website!!
Hidesertgirl
I pollinate tomato flowers using an electric tooth brush. I vibrate the stem just below the
flower and the pollen bursts out. The vibration simulates a bee. It works!
Kim
I just learned about this while shopping for plants…another customer who had been gardening for 0ver 20 years was given this bit of knowledge only last year. We’re ready with a paintbrush and may go for the vibrating child’s toothbrush, too!
Michelle Colston
Does hand pollinating work on female flowers that haven’t opened yet? I’ve had a couple fruits that started wilting (unpollinated) bc the flower never opened…
Aaron (Mr. DeannaCat)
Hi Michelle, the flower should open at some point but we have peeled open older flowers and pollinated them, especially if it has only been a day or two since they were open.
Beth
We have lots of fun using saved seed! We always plant about 3 varieties of summer squash and at least 3 varieties of winter squash with new seeds. We also however also plant saved seeds and thoroughly enjoy the different fruits. Zumpkins (zucchini/pumpkin crosses) and squmpkins (spaghetti squash/pumpkin crosses) being the favourites. If you love squash- this is worth it! Our squmpkins provided 6-12 cups of very tasty food each!
Aaron (Mr. DeannaCat)
That does sound like a lot of fun! Glad you enjoy growing them!
John Wallace
Thanks and very well done ,loved the sense of humor, from New Zealand. Just starting our spring and like last year very wet. Lost heaps last year which I put down to it being wetter than normal but now I know.. Like every tomatoe flower has to be a tomatoe , I ensure they are all pollinated morning and night , the same now with my courgettes / zucchinis . Many thanks.
Jane
Interesting and helpful! I wondered what had happened to my teeny squash. Off to check out the flowers now.
(P. S. Turn off the radio in the background next time 😉 )
Chris
Not all squash are the same species. there are 4 species, and some can cross pollinate each other, while other combinations don’t work, so it’s complicated.
Cucurbita pepo is acorn, delicata, and summer squash, zucchini, and pumpkins
Cucurbita moschata is any of the beige squash, including butternut, long-island-cheese, canada-crookneck etc…
cucurbita maxima is hubbard, buttercup, and many of the larger squash.
Cucurbita argyrosperma is Cushaw squash.
Squash within the same species can always cross pollinate. Squash in different species can sometimes cross pollinate. certain combinations work better than others. Pepo can cross with argyrosperma. moschata can cross with any other species. maxima only crosses with moschata.
Aaron (Mr. DeannaCat)
Thanks for sharing!
Mary Weatherby-Berg
Found you today…gonna give you a try. Your life story is very interesting. So glad you found your true calling and your passion!
Aaron (Mr. DeannaCat)
Thanks for reading Mary, hopefully we will hear from you in the future!
Luli
Wow this is so helpful to know! Last summer EVERY SINGLE ZUCCHINI on my plant rotted and died off. I was so frustrated I gave up and pulled out the whole plant out to make room for something else. I will try this method. Thank you 🙂
Samantha
Hi! I’ve tried hand pollinating them but they still don’t make it. Do I need to pollinate them a few times in a few days? Or…?
Aaron (Mr. DeannaCat)
Hi Samantha, I’m not sure what the problem could be? Usually hand pollinating the squash once is sufficient provided your using viable pollen from a male squash flower. If your squash plant is young, sometimes they need some time to adjust before producing fruit regularly. Blossom end rot due to a lack of calcium in the soil or dry conditions can also lead to fruit falling off prematurely. Hope that helps and good luck!
Esther
Thank you for this! I either get male or female flowers on alternating weeks, so try to hand pollinate like you described I’m wondering how long a male flower will keep in the fridge, or what would be your preferred way to keep the pollen fresh?
Aaron (Mr. DeannaCat)
Hi Esther, the flower would probably last for some time in the fridge. The one thing that will be a problem for the pollen is moisture, with that, just be sure to keep the flower dry and the pollen should stay viable for some time. Usually as squash grows you get a better mix of male and female flowers so it will usually even out with time. Hope that helps and good luck!
Maxine Manukau
Thank you for the tip. I’m going to try this. Lost lots last year.
Aaron (Mr. DeannaCat)
It really can make a big difference!