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The Cucurbit cousins – squash, cucumbers, melons, gourds, and pumpkins – have a reputation for poor pollination. You may find that your plants are covered with flowers, yet you get few fruits. Why? There are a number of factors that can contribute to pollination problems, but first, it helps to understand a little bit more about the Curcubit’s.
Members of this family have separate male and female flowers and in order to yield fruits, cross pollination needs to take place. This is when the pollen from a male flower is transferred to a female flower. It’s easy to tell the two types of flowers apart; male flowers have a straight stem beneath the bloom, while the female flowers have an immature fruit under the bloom. Only the female flowers will develop into a fruit. If no pollination takes place, that immature fruit will rot and fall off.
Savvy gardeners may also notice that when Curcubit’s initially begin to bloom, the plants produce only male flowers. Don’t worry! This only lasts for a week or two, with plenty of female flowers soon following.
What causes poor squash pollination?
- Too few bees and pollinators to move the pollen from the male to the female flowers.
- A stretch of very cool or very hot weather when the flowers are in bloom.
- Wet weather, or badly timed watering will affect pollen quantity and quality. If you must water, avoid early morning when the blooms first open. As well, irrigate only the soil, not the plant.
What’s a gardener to do?
As your Curcubit crops come into bloom, there’s no need to cross your fingers and hope for the best! Instead, give Mother Nature a helping hand by hand pollinating. Hand pollinating is quick and easy, and can seriously increase your yield.
Before you begin, grab a q-tip or a small bristle paintbrush, or pluck a just-opened male flower from the plant. If using a q-tip or paintbrush, press it gently to the anther of a fresh male flower and transfer the pollen to the stigma of a female flower. If you want to pollinate using a male flower, pick a good looking specimen from the plant and remove the petals to expose the anther. Then, simply press it against the stigma of the female flowers.
In my garden, hand pollinating cucumbers, zucchini, and squash results in more fruits per plant and an earlier harvest. Yet, for certain crops, like edible snake, bottle, and luffa gourds, it’s essential to hand pollinate. Many gourd flowers open at night, a time when there are fewer pollinators. Hand pollinating newly opened female flowers results in an excellent harvest.
For more on growing cucumbers, check out the following articles:
Do you hand pollinate your crops?
Can you think of any reasons why hand pollination won’t work? I have to keep my zucchini covered due to the dreaded squash vine borer and pollinated by hand every day last summer and got literally one zucchini. One. This year seems to be following the same trend. I pollinate the female with a paintbrush and they still inevitably stay 1”-2” long, turn yellow, shrivel and fall off. We are at a consistent minimum temp of 90 degree humid days here in Northern VA 7a. Does anyone else experience this?
Hmmm good question! First, maybe try taking a male flower and pollinating with that. You will likely get a more thorough pollination. Two, the heat and humidity affects pollen quality and that may be a contributing factor. I would suggest pollinating early as soon as the flowers open and pollen is the best quality. I hope this helps! – Niki
I’ve got a zucchini plant has only male flavor and it’s been only one week since it has been flowering is it normal that you only get mail flavor in the beginning and how much how long do I have to wait for female flowers to grow?
The female flowers typically arrive 7 to 10 days after the males, but it varies depending on the health of the plant and the conditions where it’s growing.
My one and only cucumber plant in the greenhouse has produced only female flowers. the only other flowers in the greenhouse are on the tomatoes. Can I cross pollinate with those ? Bees aren’t fussy !
Good question but nope, they aren’t compatible. If you are growing a greenhouse type of cucumber it may be parthenocarpic which produces only female flowers and don’t require pollination.
Hello ,so glad I open this ,cause I almost pulled out from the roots all my summer squash .all of their flower are long and when I see flower with a bud under Im so happy ,but after a few days they all dry out.I will dry this hand pollination your talking about.
Thanks for the info.
interesting – may try one last time – but last year none of the flowers on my zucc. plants were female(according to the description above)
Hi Niki,
Thanks for the article, very interesting. How long do female squash flowers typically stay open for? I have some starting to flower now (in an indoor hydroponic setup) and was wondering if I needed to pollinate any open flowers each morning, or if they’ll last until the weekend and then I can pollinate all the open ones then?
Thanks,
Miles
That is a great question! I would pollinate them as they open as the pollen quality is best then and you’re more likely to have pollination occur. You can use a clean, dry small paintbrush to transfer pollen, or a q-tip. Good luck! – Niki
Hi, it is officially fall and I am still getting green zucchini growing. However, not fully grown. Should I put a blanket over it or should I just pick them young and eat them? Very informative website. Thanks!
Good question! If you have a few weeks before your first expected frost date you can let some mature.. if it’s imminent, I’d pick them as baby zucchini. 🙂 – Niki
Do I have to wait until the female flower opens in order to hand pollinate or can I open it? I have about 4 or 5 yellow squash that are about 3 in long but dont ever see the flowers open. I only have 1 male flower open now. Also.. how do I know when the squash is good to harvest? Thank you!
You have to wait until the female flower is open; otherwise the stigma may not be receptive. They’re usually open by mid-morning. Summer squash can be harvested when they’re very small (2-3 inches long) or you can wait until they’re larger. The larger they are, the thicker the skin and the larger the seeds will be. Most people prefer to harvest them when they’re about 6 inches long.
I’ve never hand pollinated. I’ve left it up to fate. I’ve got some blooms on my squash, zucchini and cucumbers right now. And I’ve got q-tips. Of course this means getting done on my knees. Not the favorite thing for an old man. At least it’s cooler.
I have a raised bed where I planted Zucchini and Persian cucumbers, both plant are producing but when they are about 1 to 2 inches long the tips start yellowing and they don’t grow anymore and then drop off. Please help, I am new at this. What am I doing wrong?
Hi, Sounds like it could be a lack of pollination – you may want to try hand-pollinating. It could also be blossom end rot. Here’s a link with some good info on that issue – https://pender.ces.ncsu.edu/2013/05/why-are-my-squash-rotting/. Good luck! – Niki