Why Do Zucchinis Rot on the Vine?

Why Do Zucchinis Rot on the Vine

The blossom ends of zucchini, and other summer squashes, begin to rot because of the lack of calcium within the fruit, which causes blossom-end rot.

Blossom-end rot is a common problem that affects zucchini and other summer squashes. The rot begins at the blossom end of the fruit and within a few days, the entire fruit is rotten. The lack of calcium within the fruit is the primary cause of blossom-end rot. Most cases don’t require calcium application to soil.

The lack of calcium within the fruit is the primary cause of blossom-end rot. Calcium is essential for proper cell development and function. When there’s not enough calcium in the fruit, the cells break down, causing the blossom end to rot.

Blossom-end rot is most often caused by a lack of calcium in the soil. This can be due to several factors, including:

  • Excessive nitrogen fertilizer, which can lead to rapid vegetative growth at the expense of fruit development
  • Inadequate irrigation, which can lead to drought stress and prevent the plant from taking up calcium from the soil
  • Excessively wet or dry soil conditions, which can also prevent the plant from taking up calcium from the soil


Zucchinis are a summer squash that are typically harvested when they are about 6-8 inches long. However, if you let them grow too long, they can begin to rot on the vine. The reasons for this are twofold. First, zucchinis have a high water content, which can make them susceptible to fungal infections. Second, as zucchinis age, their skin becomes tough and difficult for insects to penetrate. This combination of factors can lead to rot setting in and causing the zucchini to deteriorate.

There are several things you can do to prevent your zucchinis from rotting on the vine. First, water them regularly and make sure they have good drainage. Second, pick them when they are young and tender. Third, keep an eye out for pests and diseases and treat accordingly. With a little care, you can enjoy fresh zucchinis all summer long!

The Science of Rotting Zucchinis

When you leave a zucchini on the vine for too long, it will start to rot. The process of rotting is caused by bacteria that break down the zucchini’s cellulose and produce methane gas. This gas makes the zucchini’s skin turn brown and mushy. If you’ve ever wondered why your zucchini rots on the vine, now you know!

The Enzymatic Process

Zucchinis rot because of a process called enzymatic browning. Enzymatic browning is when enzymes in the zucchini react with oxygen in the air to turn the zucchini brown. This process is accelerated by warmer temperatures and higher humidity. You can slow down enzymatic browning by storing your zucchinis in a cool, dry place.

The Bacterial Process

Zucchinis rot on the vine due to a bacterial process called cellulose decomposition. This is when bacteria break down the cellulose in the zucchini, causing it to rot. The bacteria that cause this are usually found in the soil, and they can enter the zucchini through any cuts or bruises on the skin. Once the bacteria are in the zucchini, they release enzymes that break down the cellulose. This process makes the zucchini softer and mushier, and it also produces a foul odor. If you have ever cut into a rotten zucchini, you will know this smell!

Cellulose decomposition is a natural process that happens to all fruits and vegetables over time. However, there are things that you can do to prevent it from happening too quickly. For example, you can pick zucchinis when they are still firm, and you can avoid bruising them when you handle them. You should also store them in a cool, dry place away from direct sunlight. If you do all of these things, your zucchinis should last for several days or even weeks before they start to rot.

The Causes of Rot

Zucchinis can rot on the vine for a number of reasons. The most common cause of rot is fungal infection. Fungi can enter the zucchini through the flowers or any other open wound. Once the fungi enter the zucchini, they release toxins that can kill the plant. Other causes of rot include bacterial infection, physical damage, and extreme weather conditions.

Poor Air Circulation

Poor air circulation is one of the leading causes of rot in zucchinis. The fruit needs to be able to dry out quickly after being watered, and if there is not enough air circulation, the moisture will stay on the zucchini and cause it to rot. Make sure to plant your zucchinis in an area where they will get plenty of air circulation, and water them in the morning so they have all day to dry out.

Excess Moisture

One of the primary causes of rot is excess moisture. When zucchinis are allowed to remain on the vine for too long, they will absorb too much water. This can cause the flesh of the zucchini to become waterlogged, leading to rot. To prevent this, zucchinis should be harvested on a regular basis. It is also important to water zucchinis evenly. Avoid over-watering or letting the plant become too dry.

Poor Soil Drainage

One of the primary causes of rot on zucchini plants is poor drainage in the soil. If water cannot drain properly away from the roots of the plant, it will begin to pool around them and cause the roots to rot. This can happen even if the soil seems to be dry on the surface.

To help improve drainage in your soil, mix in some organic matter such as compost or peat moss. You can also add some sand to help with drainage. Be sure to test your soil before planting to ensure that it has the right pH level and that it drains well.

Another cause of rot can be too much moisture on the leaves of the plant. If the leaves are constantly wet, they can develop fungal diseases that will spread to the fruit and cause it to rot. Be sure to water your plants at the base, rather than wetting the leaves, and remove any dead or decaying leaves from around the plant to help prevent disease.

The Prevention of Rot

Zucchinis, like other vegetables, will rot if not harvested in time. The main cause of rot is fungi, which enters the fruit through wounds. Fungi grow best in warm, wet conditions, which is why zucchinis often rot on the vine during hot, humid weather. There are a few things you can do to prevent your zucchinis from rotting.

Proper Air Circulation

Proper air circulation is key to preventing rot. Make sure your zucchini plants have enough space between them to allow air to circulate. If you are growing zucchinis in a greenhouse, make sure to open the vents or doors on hot days to prevent the build-up of heat and moisture.

Proper Soil Drainage

One of the most important things you can do to prevent rot is to ensure that your plant has proper drainage. This means that when you water your plant, the water should be able to drain away quickly, without pooling around the roots of the plant. If water is left standing around the roots of your plant for too long, it can cause the roots to rot.

There are a few ways that you can improve drainage in your soil. One way is to add organic matter, such as compost, to your soil. This will help to create space in between the soil particles, which will allow water to drain through more easily. Another way to improve drainage is to make sure that your pots have drainage holes in the bottom. If you are growing plants in pots without drainage holes, you will need to be extra vigilant about not overwatering, as it will be very difficult for the excess water to escape.

If you think that your plant may be suffering from rot, there are a few things you can do to try and save it. First, check the root system of the plant. If you see any dark or mushy roots, they will need to be cut away. Once you have removed all of the affected roots, replant the plant in fresh soil with good drainage. Water lightly until new growth begins to appear, and then increase watering as needed.

How do you stop blossom end rot on zucchini?

Blossom end rot is a common problem when growing zucchini. It is caused by a lack of calcium in the plant, which can be caused by several factors. One way to prevent blossom end rot is to insert calcium carbonate or an anti-acid tablet like Tums at the bottom of the plant. These tablets will dissolve within hours and calcium will become available for the plant.

A drip system can also be used to distribute calcium. Calcium chloride or calcium nitrate can be used for this purpose. Regular watering with a high-quality fertilizer will also help to prevent blossom end rot.

There are several things that can be done to prevent blossom end rot from occurring in zucchini plants. By taking preventive measures, such as inserting tablets of calcium carbonate or Tums at the bottom of the plant, growers can ensure that their plants have the necessary amount of calcium to prevent this problem from occurring.

Why are my zucchinis dying on the vine?

If you’re growing zucchini (Cucurbita pepo) and the fruits are dying on the vine, it’s likely due to poor pollination. Zucchinis need to be pollinated by bees or other insects in order to produce fruit. If the weather is rainy, it can prevent bees from being active, which can lead to poor pollination and rotting fruit.

There are a few things you can do to improve pollination and prevent rotting fruit:

  • Make sure your zucchinis are getting enough sun. They need at least 6 hours of direct sunlight per day.
  • Check the flowers regularly and hand-pollinate them if necessary.
  • Remove any diseased or damaged fruits from the plant.

With proper care, your zucchinis should start producing healthy fruit in no time!

How do you fix zucchini stem rot?

To fix zucchini stem rot, you need to remove the affected part of the stem and then treat the wound with a fungicide.

Zucchini stem rot is a common problem that can be caused by several different things. The most common cause is too much moisture, either from too much rain or from irrigation. This can cause the zucchini plant to develop a fungal disease called Phytophthora, which can kill the plant. Another common cause of zucchini stem rot is herbicide damage. This can happen if the zucchini plant is sprayed with an herbicide that is not labeled for use on zucchini. The herbicide will kill the leaves and stems of the plant, and the plant will eventually die.

There are a few things that you can do to try to fix zucchini stem rot. If the plant is still alive, you can cut off all of the affected leaves and stems. This will help to stop the spread of the disease. You can also try to treat the plant with a fungicide. This will help to kill the fungus that is causing the problem. However, it is important to note that fungicides will not work if the problem is caused by herbicide damage. In this case, the only thing that you can do is to remove the dead plants and hope that new plants will grow in their place.

If you are having problems with zucchini stem rot, there are a few things that you can try to do to fix the problem. However, it is important to note that some causes of zucchini stem rot cannot be fixed and you will just have to start over with new plants.

Tammy Slater

Tammy Slater is the founder of arew.org, a home and garden blog that provides inspiration and resources for homeowners and renters alike. A self-taught DIYer, Tammy loves nothing more than tackling a new project in her own home. When she's not blogging or spending time with her family, you can usually find her rooting around in the garden or at the hardware store.

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