Are Your Zucchinis Rotting Before They Grow?
ORIGINALLY FROM JULY 2020, UPDATED AUGUST 2026
July is the peak season for summer squash. Yours are probably out in full force, bursting with color and growing rapidly with each passing day. Or you might be like some of my friends – seeing something go awry with their summer squash, especially their zucchinis. Is this happening to you too?
What’s Happening to Your Zucchinis on the Vine
It takes love and care to grow a garden from the ground up. While even the most well-intentioned gardeners can set their plants up for success, sometimes nature shows up to remind us who’s truly in control. And when it comes to summer squash, there are a couple of things that can (and do) go wrong.
Fruit is rotting from the flower end
Your zucchinis are growing! However, before they were ripe enough to pick, the fruit quickly turned brown and rotted. If you see the flower end of your fruit beginning to rot, this is a symptom that’s both super common and easily corrected. The disease that causes the brown, rotted areas is known as blossom end rot.
The flowers are falling off
Not all dropped flowers are the same. Let me start by saying that male flowers will fall off after they have been open. This happens because the bees have done their job, so it's job is complete… nothing to worry about. However, if the flowers fall off before they even open, this is something to get curious about.
Let’s dig into what is causing your zucchini to rot on the vine or flowers to fall prematurely.
3 Reasons Your Zucchinis are Rotting on the Plant
Zucchinis are wonderful summer plants to grow, but can be frustrating when you find them rotting on the vine before you can pick them.
1. Poor pollination
If you see the flower end of your fruit beginning to rot, this is a symptom of poor pollination. This is not from contaminated soil or a “bad” plant, as many might think. Luckily, this is super common and easily corrected.
Zucchini plants have both male and female flowers. The male flowers are on a straight stem while the female flowers have a little rounded bulge at the base of it. When your flowers are open, you can hand pollinate the female from the male flower. Voilà!
2. Over watering
If you see the flowers fall off before your zucchini before it fruits, this can be for a couple of reasons. One reason could be that the soil is staying too moist and not drying out enough.
If that’s the case then adjust your watering schedule. The goal is to water deeply and then wait until the soil has dried out a couple of inches before watering again. The soil may look dry at the surface, but feel down a few inches. Is it still moist? Remember that as the plant grows, you will water deeper and less often because the root systems grow wider and deeper. Also, these plants prefer well-draining soil. If you have more clay-like soil – which does not drain well – then it’s best to plant your summer squash on a high mound or in a raised bed with good, rich soil.
The other reason you will see flowers fall off your zucchini plant prematurely is if the temperatures are too hot.
3. Temperatures are too hot
When the daytime temperatures reach 90°F for a number of days, you may see the flowers and underdeveloped fruits drop off. You can correct this by providing regular water to the plant. This prevents the plant from drying out during times of excessive heat.
Now, you might be confused since I just mentioned that over watering also causes the flowers to drop. I know it sounds like a contradiction. This is why it’s important to:
Know your soil
Understand how the water is moving through the soil
Know how water is evaporating out of the soil
Equally as important to understand is how the plants are being irrigated. The way you water will adjust accordingly as your plants grow. From here, you can identify what the problem is and find the most effective, sustainable solution to manage it.
Ways to Grow Together
Your garden and plants give you clues. It's up to you to interpret these clues. I invite you to get curious and investigate a bit more before giving up or reaching for a pesticide.
After I've gone through a few possible reasons for a problem, whoever I’m helping usually has an “aha moment.” All it takes is one mention of something that fits their scenario of what could be going awry. That’s why collaborating with other gardeners or working with professionals is a smart choice… you don’t have to do this alone!
Send me an email with the garden problems you are facing, I’d love to hear from you and help you work through them.