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Zucchini does not grow properly: several possible reasons why the fruit turns yellow and rots

Actually, they are considered extremely easy to care for. But again and again amateur gardeners report various problems with growing zucchini. Either they turn yellow and rot, or they do not grow properly and remain small. We list several possible reasons and explain how you can prevent them. To help zucchini grow and become ready for harvest.

Possible reasons why your zucchini doesn’t grow properly

Zucchini do not grow possible causes

Zucchini is one of the most popular vegetables among home hobby gardeners. However, it happens from time to time that suddenly plants that have developed splendidly immediately after planting, suddenly cease to grow, turn yellow or bear little and small fruits . This could be due to several reasons. We list the most common ones.

The fruits remain small: wrong variety planted.

Not all varieties of zucchini give abundant yields. There are also varieties that are disease resistant. Such are, for example, “Tigress”, “Green Machine”, “Burpee Golden Glory”, “Yellow Fin”. Each variety has its own requirements for soil, location and care. You should adhere to them so that the vegetable develops well and bears many fruits.

Zucchini does not grow properly: poor pollination.

Zucchini pollinate by bees

Zucchini are pollinated by insects. Bees, bumblebees and the like are a rarity in or near big cities. You must first attract them to the garden with other bee-friendly plants. In the case that you grow the zucchini in the greenhouse , then you can help with pollination yourself. There are also varieties of zucchini that bear healthy fruit even without pollination. Such are for example “Easypick Gold”, “Partenon” or “Cavili”.

Help, my zucchini turn yellow! Problems with the condition of the soil

Zucchini does not grow turn yellow and rot causes

If the fruits turn yellow, then you should check the soil composition. Often the following is found in the laboratory:

  • The soil is low in nutrients. Especially a lack of calcium can negatively affect the quality of the fruit.
  • Loamy soil: a loamy, poorly aerated soil prevents the absorption of nutrients through the roots. You can fertilize all you want and still the plants will not get enough nutrients.
  • Too little water: zucchini are true sun worshippers. They prefer a location in full sun. However, water evaporates more quickly from the soil there. To prevent this, you can mulch the soil.
  • The wet soil in combination with bad weather (temperatures below 20 degrees Celsius at night, large temperature fluctuations and a lot of rain) can lead to rotting.

The right location and planting partners are crucial

Zucchini different varieties at a glance


Not enough sun: zucchini thrives best in full sun and needs six to eight hours of direct sunlight daily. If the vegetable doesn’t get enough sunlight, its leaves turn yellow and the fruits remain small. Most pollinating insects also prefer plants in the sun, so these are the first to pollinate.

Choosing the right neighbors can also have a positive effect on yields. Zucchini are heavy feeders, which means they need lots of nutrients to grow quickly and healthily. The vegetable gets along with other heavy growers that also need a lot of water. Potatoes, tomatoes and Brussels sprouts are out of place next to zucchini.

If the zucchini do not grow properly, but turn yellow and rot: diseases and pests.

Diseases and pests in zucchini dangerous

Powdery mildew: a fungal disease in which the plant leaves turn gray-white and look as if they are covered with dust. For prevention helps if you plant the individual plants at a distance of at least 60 cm. This will improve aeration and the leaves will dry faster.

Marginal bugs: they fly very fast and therefore often go unnoticed until it is too late. The larvae eat the leaves and shoots of the plant, injecting toxins. The plant dies. You can wrap the shoots at the bottom with aluminum foil.

Blossom end rot in zucchini: This nutrient deficiency occurs when the plant does not get enough calcium . Plant the zucchini at a wider spacing, leave enough room in the pot for the root system to spread and fertilize in moderation. You can additionally loosen the soil. Water regularly (better to water little, but regularly, than a lot, but rarely).

Bacterial wilt: there are bacteria that cause certain vegetables to wilt faster. Cucumbers are particularly affected, but zucchini can also get sick. The bacteria are transmitted from plant to plant by cucumber beetles. So if you notice the pest in your vegetable garden, be sure to control it. This is because bacterial wilt is a dangerous disease that causes plants to die. Rescue attempts are often forgiven.

If the zucchini does not grow properly, then act quickly.