Zucchinis Turning Yellow- Reasons & Remedies to Know


We all know that zucchini is one of the most amazing summer squash varieties to grow in the vegetable garden, also, they are pretty easy to grow. But sometimes, home growers face some difficulties growing them.

As you are reading this article, you also may be facing something troublesome. And more importantly, if you are struggling for your zucchinis turning yellow, then don’t fear anymore.

As this article is compiled with the possible reasons and remedies of happening this, you will find this helpful. Moreover, there is an FAQ section for in case you keep asking yourself something.

Okay, let’s begin then, shall we?

Photo of zucchinis on a white background
Photo by Chernetskaya

What Causes My Zucchini Turning Yellow?

Well, there are two specific reasons for yellowing your zucchini. Before you go for the solutions, you need to know what leads to it in the first place. So, let’s have a look what can be liable for this issue:

  • Poor pollination
  • Blossom end rot

Now, let’s get into the causes in detail and the possible steps to stop these.

Problem 1: Poor Pollination

For having a clear idea about it, you have to know the ‘zucchini biology’ first. We will talk about it in brief and then move on to the next step.

Zucchini plants produce both male and female flowers. The male blossoms grow on long, have slender stems, and need to pollinate the female flowers. Female flowers have short and swollen stems that develop into the tender zucchini fruit.

The problem arises when little bee activities occur or the male and female blossoms don’t open at the same time. Yes, in these cases, you will get poor pollination. Now, the question is, what affects the bee activity?

The answer is wet or windy weather in the early season. Moreover, the temperatures that are extremely hot or cold, make pollen less viable.

What Are the Symptoms of Poor Pollination?

When the plants are not appropriately pollinated, they develop a few fruits or fruit that turns yellow and drops. This situation is known as fruit abortion (in the horticultural terms) as very few pollen grains pollinate a female flower.

In fact, when pollen rates are low, zucchini also can be stunted and look pinched or misshaped. In general, yellowing takes place from the blossom end of the fruit and moves down toward the stem.

Solution: In this place, you may have understood that you can’t reverse the yellowing as there is a problem since the pollination. So, you should now spend extra time to plan your garden and monitor the plants while they’re flowering.

Thoughtful garden planning is a must to have the best chance for successful pollination and a plentiful crop. So, let’s plan for pollination:

  • Plant your zucchini in sun
  • Space the plants 12-15 inches to encourage flowering and visits from pollinators.
  • Interplant zucchini with blooming annuals that will attract bees and open at the same time as the squash bloom.
  • Don’t use insecticides that kill bees. But, in the evening, bees are less active. So, you can apply them in the evening.

Another option is there for you, guess what? Well, it is to pollinate by hand. Yes, sometimes, you may need to take matters into your own hands(literally) for ensuring a good zucchini crop.

Actually, the problem is, zucchini pollen is somewhat sticky and usually doesn’t blow from flower to flower by wind (or simply by shaking the plant). So, you can try the hand-pollination techniques. To do so:

  • Pick a male flower
  • Peel back the petals of the flower
  • Rub the structure at the center of the flower, covered with yellow pollen- into the center of the open female flowers.

Worth noting, pollen only works for one day and pollen is at its best when the flowers first open in the morning. So, if you want to pollinate by hand, make sure you don’t waste time and make it your first chore of the day.

Problem 2: Blossom End Rot

This is another reason for yellowing zucchini. The reason behind blossom end rot is a lack of calcium in the fruit. Calcium is important to hold the cell walls of plants together.

Calcium deficiency also results in stunted growth, misshaped leaves, and yellow and rotting fruit. So, you need to be careful about it from the very beginning.

Another cause for blossom end rot is irregular watering. If your plants don’t get enough water they will be unable to take the minerals when needed.

Solution: Add calcium to the soil before zucchini plants are grown. Also, use garden lime and Epsom salts about 6-8 before planting your zucchini plants.

Hence, a point to be noted, if you add Epsom salts to the soil once zucchini have blossom end rot will do more harm than good. So, make sure you don’t use it too much.

To solve the second problem, water the plants regularly and deeply. Try to provide 1-2 inches of water when the top of the soil seems dry.

Zucchinis Turning Yellow – FAQs

Question: Should I remove the rotted fruit if blossom end rot happened?

Answer: Yes, remove the rotting or decaying fruit.

Question: Should I check the calcium level when blossom end rot takes place?

Answer: Actually, it’s better to look at the level of nitrogen, not calcium. Because increased nitrogen will increase leaf growth and more leaves need more calcium.

Question: What is the best fertilizer for zucchini?

Answer: The most important thing is, the fertilizer has to contain nitrogen. An all-purpose garden food like 10-10-10 works best for zucchini plants.


So, we are done. You now know the ins and outs of why your zucchinis turning yellow and how you can fix it.

At the end of the article, we’d like to say you that you always should take extra care of your plants. Try to water them properly, make sure they get enough sunlight, and take enough measures when they get sick.

And apart from all of these, you can troubleshoot now, go for it. Good luck!

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Celina Nance

It’s been a life-long wish of Celina Nance to have a lawn full of colorful flower beds. But living in Arizona city, that seems kind of impossible. But Celina Nance didn’t stop and created a full-form balcony garden instead. And he often shares stuff that he does/solves/innovates throughout the journey.

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