How your plants pollinate

Our teaching garden at Seed Savers Exchange demonstrates important seed saving concepts. Throughout the season, I’ll take you on a tour to discuss some of these concepts. The first stop on our tour is the Pollination bed. It is important that seed savers understand how their plants pollinate in order to prevent varieties in the same species from cross-pollinating. In this bed we are growing tomatillos, spinach, amaranth and cucumbers to demonstrate different flower types.

Flowers exist to facilitate pollination, which occurs when pollen is transferred from the male anther to the female stigma. In some plants, this occurs before the flower even opens. In other plants, pollinators such as humans, insects, or wind are required to transfer the pollen.

Tomatillos have perfect flowers. These flowers have both male and female organs, allowing for self-pollination. Tomatillos are “selfers” that can pollinate before their flower even opens.

Selfers are good plants to choose if you are a beginning seed saver. Selfers include tomatoes, peppers, beans, peas, and lettuce. And remember, in nature there are always exceptions to the rule—just because a plant can self-pollinate doesn’t mean that it can’t cross pollinate.

Female spinach plant

Male spinach plant










Spinach and cucumber have imperfect flowers. These flowers have either male or female organs. If male and female flowers are on different plants, the species is dioecious. In order to produce seed, pollen must travel from male plants to the female plants. Spinach is dioecious, and requires the wind to pollinate. Asparagus is also dioecious, and relies on insects for pollination.


Female cucumber flower

Male cucumber flower







Cucumber flowers are imperfect as well. However, cucumbers—as well as squash, melons, watermelons, and gourds—are monoecious, with male and female flowers on the same plant. Notice the immature fruit at the base of the female flower pictured above. In the Cucurbitaceae family, insects are required to transfer pollen from male flowers to female flowers for pollination to occur. Corn is also a monoecious plant with imperfect flowers (the tassels represent the male flowers, and the developing ears represent the female flowers), though corn relies on wind for pollination.

Take a few minutes to identify male and female flowers in your home garden. Congratulations you are officially one step closer to becoming a seed saver!

« Back to Blog Home


  1. What about those that *don’t* have male and female – have several types of zucchini, for 2-3 years now I get lots of flowers that look like the males…but NONE that are female *to* pollinate. I haven’t been able to get fruit or seeds…and using heirloom varieties this is extremely frustrating.

    • Check with the seed company your getting your seeds from. Make sure they are true heirloom seeds, and if they are, some varietys require a ‘pollinatior’, which is sometimes a completely different variety.

      • Interesting – but then they wouldn’t be heirloom? I’ve got black beauty and green zucchini – planted some of the gold but they don’t seem to grow well. Some of the seed came from here, some from other sources. Will check into that – thanks.

        • Christy says:

          Heirloom varieties require pollinators more so than hybrid versions, so that’s not a problem. An heirloom variety as defined by Seed Savers Exchange is an open-pollinated plant that has historical importance. I haven’t been able to figure out what’s up with your all-male plants, but I’m working on it!

    • Christy says:

      I talked to our hand squash pollination expert at Seed Savers Exchange, and she gave me the following information.

      First, make sure you’re looking in the right places for the female flowers. They’ll come out on the arms that branch out from the main cluster, tucked into spots pretty tightly. You’ll have a difficult time finding them when they first appear. If your plants are experiencing stress due to pest pressure or weather, then it’s possible that these females are being aborted quite young. If this happens, those little flowers will turn a sickly yellow color, get wrinkly, and fall off. They’re quite small, so it’s possible to easily miss them.

      Second, squash varieties usually grow a flush of male flowers 2-3 weeks prior to female flowers. So, don’t give up hope!

      I have some questions to help with your situation. First, do you have cucumber beetle? If there’s a high population of this little bugger, then it could be stressing your plants out enough that they’re aborting all female flowers. Second, how warm is your climate? If it’s quite hot, the same thing can happen in an overstressed plant.

      I recommend trying different varieties, and possibly look at the environmental conditions. If this has happened for several years in a row, it leads me to believe that something could be happening in the garden. Heirlooms, and any sort of squash really, are highly unlikely to produce only male or female flowers – and no one I’ve talked to has ever seen it happen.

      If you have any questions, keep asking! Hopefully we can continue to help.

      • Thanks – there *may be* is some females coming on…down further near the ground it’s not exactly looking like baby zucchini yet but the stems are thicker. No pests – about a month ago I noticed a couple leaves with a hole in them, lightly sprayed and have no further issues. The first year I thought it was maybe too shady or not fertile enough soil.This year hopefully it’s found the sweet spot in the garden.

  2. is one of the ones I planted – doesn’t say it needs a pollinator. But nearby is a green variety – neither has anything but flowers. Have tried fertilizing and not; this is the 3rd year of big beautiful plants with loads of big yellow flowers and not one zucchini. Am from the midwest and can’t ever remember zucchini crop failure, let alone 3 years of it. :-( Very frustrating. The golden variety doesn’t do much either – doesn’t seem as hardy as the others.

  3. I’ve seen tomatilloes remain fruitless on several occasions when only one plant was in the vicinity. Since then, I’ve seen some remarks that indicate tomatilloes are self-sterile, and due to experience, I tend to believe that.

  4. Dev Vallencourt says:

    Don’t forget that zucchini requires bees for pollinating. If you live in GMO corn/soybean country, you likely have a severe shortage of bees. The bee shortage, combined with two years of drought, will affect any fruiting.

    When you see about 3 male squash flowers, start looking for one with a bulge behind the bloom– the female bloom. Get out your long bristled paint brush and lightly transfer some male pollen to the female bloom. This is usually best before 10 am. Within a day or so, you should notice the female’s bulge starting to grow– the squash fruit.

    Attract bees early in the season by letting your mustards and radishes go to flower. Keep flowering bee plants in your rows and along the garden edges. You can teach any available bees to come to your garden.

    Don’t forget that bumble bees are also good pollinators, too.

  5. Appreciate the feedback but there is no females. There’s six plants in a raised bed, waist high, loaded with flowers but all male. Not one flower has the bulge. Plenty of bees and others around and I’d assist with pollination if there was something to pollinate. Somehow I’m not sure transferring pollen from one flower to another is enough if NONE have the bulge at the base. That’s been the case every year. I went over it this morning again – none with bulges at the base.

  6. Christy says:

    I hope you get some fruit some year!

    If you want more advice or help, feel free to use the Seed Savers Exchange forum at It’s full of great advice and knowledgeable people that can help you with any gardening concerns.

    Let us know how it goes! And happy gardening.

    • Will check it out – thanks! And if this is what it appears looks like these will be very productive. Believe I got the Black Beauty from Seedsavers. Now to get the golden going…something always happens to those! Persistence pays!

  7. The male and female flowers open at different times, both of the season and the day. If you have mainly male flowers you may just need to wait. Male flowers come on earlier in the season. They also open at different times of day than the female flowers, which is the reason that some require a polinator of a different type.

  8. Gina Martyn says:

    Great post! Informative, and looking forward to the next one in the series!