What To Do When Zucchini Fruit Turn Yellow And Fall Off?

Last updated on October 23rd, 2023 at 08:45 pm

Zucchini plants form a lot of fruits. Sometimes in the process, some zucchini turn yellow and fall off.

• Zucchini forms many flowers and fruits at once
• unfertilized fruits turn yellow and fall off
• insufficient nutrient or water supply can interfere with fruit formation
• rare diseases or pests
• fertilization may need to be done by hand

(Disturbed) fruiting of zucchini.

The zucchini continuously forms new flowers during its growing season. After these have faded, the fruits form from them. These grow until they are harvested. The fruits taste best when they are not yet so large. Regular removal of zucchini fruits stimulates the plant to form new flowers.

Note: The flowers of the zucchini are also edible. They taste especially good fried and stuffed.

It always happens that the zucchini forms fruits, which then turn yellow and fall off. Sometimes they are still very small, but sometimes they are already larger. In some summers or with certain varieties, fruits that do not develop further occur more frequently.

Causes

The exact reason for a disturbed fruit formation is usually not immediately obvious. Often it is a combination of several causes.

Insufficient fertilization

Zucchini flowers must be fertilized to develop into fruit. Therefore, a plant forms male and female flowers. Usually, the male flowers are formed some time before the female ones. For this reason, late appearing female flowers may not be fertilized. The remedy is to plant several zucchini plants with different flowering times.

The flowers are usually pollinated by insects. However, if the weather is cool and damp, the insect flight may fail to materialize. Then it helps to pollinate the flowers by hand:

• pick off well-developed male flower
• remove outer petals and expose stamens
• brush with them over the stigma inside the female flower
• pollen should remain visibly attached
• do not pollinate too many flowers

Weather conditions

Rainy and cool summers not only result in fewer insects out and about pollinating flowers. In addition, bad weather causes fungal diseases in particular to spread more rapidly. You can’t control the weather, but you can limit its impact on vegetable plants. A rain shelter will keep the plants dry. Removing an old leaf now and then also helps to ensure that enough air gets to the plants. Watering is done only directly at the root and not over the entire plant. In areas that often experience bad summers, hardy or resistant varieties are a big help.

Care mistakes

These include, for example, inadequate watering during drought or incorrect fertilizing. However, both too little and too many or the wrong nutrients can lead to yellow zucchini fruits that do not develop further and fall off.

Sensible measures

• keep soil well moist in dry summers
• water in the morning, watering thoroughly
• shade plants if necessary and mulch well all around
• take a soil sample if fertilizing does not help
• then fertilize as needed

Especially with too much nitrogen in the soil, zucchini fruits do not grow well, while the leaves sprout vigorously.

Pests and diseases

It is rather rare that pests or diseases cause young zucchini fruits to turn yellow. However, they can cause them to stop growing and fall off. Slugs prefer to eat young fruit. Fungi can quickly invade through the open areas. The zucchini rots and is rejected from the plant. Help against slugs provide slug fences that tightly enclose the plants. However, it is important to plan the fence sufficiently large, because zucchini plants need a lot of space.

Note: There are insects that eat the flowers, preventing fertilization. Even then, the zucchini fruits turn yellow and fall off.

Frequently asked questions

Do fruits of other vegetables also turn yellow and fall off?

Yes, this also applies to other fruiting vegetables that belong to the same species, such as pumpkins or cucumbers. However, pumpkins are naturally less likely to produce fruit.

How can you ensure a consistent supply of nutrients?

Zucchini grows very well in mounds or raised beds, or right in the compost pile. There, the nutrient supply is consistently good. Since the compost pile is often in a shady spot in the garden, it is also more humid there and thus the water supply is better.

How can you recognize male and female flowers?

Male flowers sit at the end of very long stems. Female flowers are already recognizable as zucchini fruits before fertilization, this is due to the thickened ovary.