Why Are My Zucchini Turning Yellow And Rotting?

Zucchini – also known as courgette in some countries – are a vegetable that resembles cucumbers, but are eaten hot more than cold. The texture of a zucchini / courgette is also different to a cucumber – drier in the whole and a little more dense than a cucumber (in my experience anyhow).

I have loved growing cucumbers, but have been less fortunate with zucchini, as they often end up turning yellow and rotting, which is always a disappointment. I thought I’d share some of the possible reasons for this and possible way to stop this from happening in the future.

Why Is The Zucchini On My Plant Rotting Before Maturing? 

If you have encountered a problem where your planted zucchini suddenly turns yellow before it even reaches maturity, you might want to take a look at the causes of this issue. There are several possible reasons for zucchini rotting, and pinpointing the exact reason for the problem can help you prevent it in the future.

Below are the reasons why zucchini rots before reaching the harvest stage.

Poor Pollination

Poor pollination is the most common culprit regarding the quick decay of zucchini. Inadequate pollination can lead to an unhealthy fruit and can cause it to turn yellow fast and fall off before it reaches maturity.

If this is the issue, you can go about fixing it using a handful of methods. The first and most straightforward technique to prevent poor pollination is to grow companion plants beside the zucchini, such as oregano and peas. These plants should help attract more pollinators in your garden, which can then improve the growth of your zucchini plant.

There is also the method of manual hand-pollinating the plant. This method can be achieved by placing the male flower right beside the female flower or using a soft bristle paint brush to gently brush the flowers to assist the plant in spreading its pollen manually.

Pests

The next most common cause of zucchini rotting is pest attacks and infestation. Pests are likely to be the leading cause of your plants’ suffering from diseases. When it comes to zucchini plants, the pest chooses your plan can also cause blossom end rot.

Pests can cause different types of viruses that will infect your plants. In most cases, these viruses can either lead to the plant dying or cause poor nourishment, leading to low-quality fruits and flowers during harvest season.

The most major garden pest you should look out for are aphids, tiny insects that love to hang around various plants. One way to prevent pests from ruining your garden is by installing a net, checking for any signs of pest infestation, and dealing with them promptly.

Learn more about different garden pests here!

Blossom End Rot

As stated earlier, blossom rot is another problem you should keep an eye out for if your zucchini tends to rot and fall off before it hits maturity. Blossom end rot can affect your plant due to calcium and other nutrient deficiency in the soil. It can also be caused by low-pH soil or the environment (too hot or too cold).

To prevent blossom end rot, ensure that soil pH is up to standards. Also, ensuring that your zone area is compatible with growing zucchini is essential. To help point you in the right direction, zucchini is compatible with USDA hardiness zone 3-9.

Zucchini Disease

Specific diseases can also cause some serious damage to your zucchini plant if left unchecked. Here are the plant infections that are known to affect zucchinis.

Powdery Mildew

This white mold appears on the plant’s flowers and leaves. You can avoid this by watering your plants during the day to ensure it dries off quickly before nightfall. Also, try to avoid overcrowding your garden to improve air circulation.

Bacterial Wilt 

Also known as erwinia Tracheophyta, bacterial wilt causes the plant to wither and causes the leaves to have a dark green and pale color. The best way to remedy this problem is by quickly removing and destroying the infected plants so they won’t spread throughout your garden.

How Can I Stop The Blossom End Rot On My Zucchini?

Prevention is always better than cure, and this remains true for gardening. Blossom end rot can be quite a headache, so it is best to take the necessary precautions so that it won’t have a chance to affect your zucchini crops.

The first step in preventing blossom end rot is to have your soil tested before you begin planting. The ground should have adequate pH levels (6.0 to 7.5) and decent levels of nutrients, calcium specifically. It is also essential to keep the soil evenly moist. Growing zucchini also requires extra care when cultivating as you should not sever the feeder roots as this can trigger blossom end rot.

It is crucial to remember that excess nitrogen in the soil can also trigger blossom end roots, so ensure that nitrogen content in the ground remains at normal levels. As such, it is recommended to avoid high nitrogen-level fertilizers and focus on fertilizers that contain micronutrients.

In instances where blossom end rot symptoms are already visible, don’t fret, as all is not yet lost. There is still a way to save your harvest, possibly, and that is by adding more calcium nutrients to the soil. You will need to expose the roots directly to calcium, and you can do this by using calcium-carbonate or anti-acid tablets. This is not 100% foolproof, but it is worth a shot.

Additionally, if you live in an area where the climate is dry and warm, you might consider using a drip system with your plants and mixing calcium chloride or calcium nitrate.

How Much Should I Water My Zucchini? 

While zucchini is generally simple to grow and requires little maintenance, it is crucial to know the vital aspects of growing this crop. The reason is that zucchini has high moisture content and is made up of 95% water, so proper watering will be essential to growing this summer squash.

First, it is vital to water the zucchini deeply with about one to two inches of water whenever the surface soil is dry. For the relatively cooler season, you can water zucchini once a week. Then, you can increase it to two or three times a week during hotter days.

In addition, using a garden hose is recommended rather than an overhead watering system. This is because the water hose can seep into the soil deeper. It is also essential to plant zucchini plants early in the day to give them enough time to dry thoroughly to avoid molds and mildew from growing on their leaves overnight.

What Nutrients Does My Zucchini Plant Need? 

As we have noted throughout the article, calcium is the primary nutrient zucchini needs to thrive. But, of course, zucchini still requires soil rich in micronutrients. If you are to use fertilizer, it is best to use a 10-10-10 fertilizer as it contains all the crucial nutrients such as nitrogen, phosphorus, and potassium. Just remember not to use fertilizers that contain an extreme amount of nitrogen.