Why Your Zucchini Plants Are Flowering but Not Fruiting

Zucchini are some of the easiest-to-grow garden plants of summer. However, one of the biggest problems gardeners have with them is that sometimes the plants fail to develop mature fruit. You might see your zucchini plant begin to produce a parade of golden flowers and, maybe, small fruit. You triumphantly bust out your recipes for spaghetti zoodles and zucchini muffins; then, one by one, each flower and fruit drops off or shrivels up. Thankfully, you can often turn the problem around within minutes and in a week or two have abundant zucchini for all your favorite recipes. Follow these 4 tips to avoid the disappointment of stubborn zucchini that won't fruit.

Why Won't My Zucchini Develop Fruit?

To answer this question, it helps to know a few botanical details about zucchini. Unlike the blooms of most blooming plants that have both male and female parts in each flower, zucchini have separate male and female flowers on each plant. This makes pollination a little bit more difficult. It requires male and female flowers to be open at the same time and a pollinator like a bumblebee to carry pollen from the male to the female flower.

Normally, a zucchini plant will produce only male flowers for the first week or two of flowering. Then it begins to produce both male and female flowers. You can tell them apart by looking at the base of the flowers; the female flowers have a swollen part (the ovary) at their base and shorter, thicker stems. The ovaries look like miniature zucchini. Only the female flowers produce fruit. You'll know that you may have a problem if your plant's female flowers never or rarely turn into mature fruit.

How to Get Zucchini to Fruit

Before definitively diagnosing your barren zucchini as a pollination problem, make sure the overall plant is vigorous and healthy. Your plant should be getting everything it needs to thrive in terms of sun, soil, and water. There are also a few common ailments to watch out for like stem rot and powdery mildew. Once you're sure that your plant is otherwise healthy, you can zero in on pollination as the problem. These four strategies will help you make sure you aren't staring at an empty zucchini plant all summer or ever again in the future.

1. Pollinate by Hand

Use a small artist's paintbrush or a cotton bud to transfer some of the pollen from a male zucchini flower to a female flower. The pollen is located on the stamen, which is the part in the center of the male flower. Dab the pollen on the tip of the stigma in the center of the female flower. You can also pull a male flower off the plant, remove the petals, and brush the stamen directly onto the stigma of a female flower.

One potential pitfall with this method is that you may have female flowers open but no males, leaving you without a source of pollen. To get around this, some gardeners proactively collect zucchini pollen, put it in a zip top bag, and refrigerate it until needed. Some gardeners actually prefer to pollinate by hand to increase fruit set even if their zucchini are already fruiting normally. This technique should be done in the morning when the flowers are first open. Each flower only lasts for about six hours.

2. Plant Two or More Varieties of Zucchini

If you have two different types or even just two plants of the same variety, you'll be more likely to have male and female flowers open at the same time. That increases the odds of pollination. Other summer squashes and pumpkins will also pollinate zucchini. Keep in mind that zucchini are self-fertile, so you don't need multiple plants for pollination. But having more than one can improve fruit set.

3. Attract Pollinators

Make your garden a hot spot for bees and other pollinators. Plant their favorite flowers and limit pesticide use and they will come (and hopefully help pollinate your zucchini). For best results, make your landscape attractive to pollinators for as much of the year as possible, so these creatures become regular guests or co-habitants. You could even try planting your zucchini among ornamental flowers. If you plant at least some native flowers, you may attract even more pollinators over time.

4. Plant Zucchini Varieties That Don't Require Pollination

This is arguably the best secret weapon option. But you may have to plan ahead of the growing season to get your seeds. In technical terms, these are referred to as parthenocarpic zucchini. Some people prefer them for kitchen use because their seeds don't develop unless they're pollinated. The nearly seedless interior gives them a smoother texture. A few popular options include 'Partenon', 'Cavali', and the aptly named 'Sure Thing'.

If all else fails, zucchini flowers are edible delicacies by themselves. And you can eat the leaves, too. But with proper care of your zucchini plants, and using these 4 tips, you may just find yourself with the opposite problem of an overabundant harvest. Then, you may want to participate in National Sneak Zucchini onto Your Neighbor's Porch Day.