Why Your Tomato Plants Aren’t Flowering (5 Reasons)

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Why aren’t my tomatoes flowering? Why aren’t my tomato flowers turning into tomatoes?! This problem can be very frustrating to a gardener, and I’ve been there myself. Whether you’re growing big beefsteak tomatoes, or small cherry types, a lack of flowers is a big problem to have.

There are a few major reasons for tomatoes not flowering, or flowers dropping off of the plants. In this article, I’ll cover the most common reasons for tomato plants not flowering or producing fruits. And of course, I’ll share some tips to fix the problem fast! Let’s get started.

Large tomato flower
Tomato flowers.

First off, tomatoes need some time to start producing flowers. If your tomatoes are still seedlings, then you may just need to wait a bit longer for them to start flowering and fruiting. In my garden, I often see the first tomato flowers forming about a month or so after transplanting them into the garden.

However, there are several stressful situations that may be impacting your tomato plant’s ability to flower and fruit properly.

Small tomato plant in raised bed
Young tomato plant before flowering stage begins.

1. Temperature

Temperature can have a huge impact on flower production in tomatoes and other plants. Generally speaking, tomatoes will set their flowers when the daytime temperatures are between 70-85°F, and nighttime temperatures are above 55°F.

So, if you happen to live in a very hot climate, a lack of flowers may have to do with excessive heat. If your tomatoes are growing in temperatures over 85°F, they may be conserving energy by producing fewer flowers. Similarly, if nighttime temperatures are staying above 70°F, this warmth can be another trigger for flower drop.

On the other side, tomatoes may drop flowers if overnight temperatures consistently drop below 55°F. So, if it is still early spring, your tomato plants may be waiting until the warmer weather arrives in summer to start flowering.

Solutions:

Firstly, plant varieties that are better suited for your climate. If you live in the desert, there are tomatoes that are better equipped to produce their fruits in the intense heat. If your climate has a shorter season, plant quick-to-ripen tomato varieties.

For hot weather, there are a few options. First, use shade cloth as needed throughout the growing season. Shade cloth blocks some of the sunlight, significantly reducing the temperature around your tomato plants. I usually recommend starting with a 50% shade cloth, covering the plants on hot days.

Second, plant at the right time of year. For example, in Florida, it is best to plant tomatoes in the winter months. This way, the plants are producing flowers and fruit during the cooler spring instead of in mid-summer.

Lastly, when it is very hot, you can try spraying cool water directly on any flowers. This cools off the flowers as the water evaporates, leading to better pollination.


2. Nitrogen overload

All plants need nitrogen to grow, but too much can cause problems. Too much nitrogen can cause tomato plants to grow lots of green foliage, but fewer flowers. This is known as the “growth habit” and can be difficult to un-do.

Instead, balance is key. Nitrogen should be in your fertilizer or soil amendments, but be sure you are adding the necessary phosphorus and potassium, too.

Solutions:

Always use a balanced fertilizer for container-grown tomatoes. This way, the ratio of nitrogen, phosphorus, and potassium will stay the same. Most tomato-formulated fertilizers will have a suitable ratio, without over-applying nitrogen.

Tomato algo plus fertilizer

For in-ground gardens, I suggest getting your soil tested. This way, you’ll know what is already in the soil, and will get specific instructions for how to amend your soil before planting. After I started testing our garden soil, our tomato harvests have exploded!


3. Humidity

Humidity is another environmental factor that can impact flowering on your tomatoes. If humidity falls outside of the ideal range, it may cause pollination issues. If a flower is not fertilized properly by pollen, it will fall off the plant. The ideal humidity for tomato plants is between 40-70% RH.

If humidity is higher than 70%, pollen may become stuck inside the flowers. This may cause the pollen to not release from the anthers, which is required for pollination to happen. If pollination fails, flowers will drop.

If humidity is lower than 40%, the dry air may actually dehydrate the pollen inside the flowers. This can cause poor contact with the stigma, leading to low pollination rate and higher flower drop.

Solutions:

  • Prune tomatoes for good airflow
  • Plant varieties that are suited to your environment

4. Watering issues

Over-watering or under-watering tomatoes can potentially lead to flower drop. If the plant is stressed from poor watering technique, the pollen in the flowers can suffer.

Watering base of tomato plant

Unfortunately, there are many issues that can lead to over or under watering tomatoes. Clay-heavy soil can lead to poor drainage which can cause the roots to “drown.” Potted plants dry out fast and need frequent watering, especially when it is hot.

Solutions:

Tomatoes grow best when they receive “even” watering. In other words, the soil should be consistently moist, but not overly wet. If the plants become too dry and begin to wilt, you’ve waited too long. If the soil is wet to the surface, avoid watering until the first several inches of soil have dried out.

Also, I highly suggest mulching tomatoes with a natural material. This helps keep moisture levels even in the soil for longer, leading to less frequent watering. The best mulches include wood chips, leaf mulch, straw, dried grass clippings, pine needles, and compost.


5. Poor pollination

Many of the issues mentioned above can cause poor pollination. Temperature and humidity can directly impact the quality of the pollen in tomato flowers, resulting in better or worse pollination. However, the actual act of pollination can be an issue, too.

Tomato flowers and early fruits
Each tomato flower has the chance to become a tomato.

Pollination is the important process of fertilizing a flower. All flowering plants rely on pollination to initiate seed production. In tomatoes, pollination usually happens one of two ways: through insects buzzing near the flowers, or wind. These physical forces cause the pollen to release and reach the stigma in each flower.

However, there are situations where pollination may be limited. The main reason for poor pollination rates is growing indoors. If you happen to be growing tomatoes inside, you will likely have to hand-pollinate your flowers to get them to set fruits. This is a simple and easy process, but it must be done.

Another scenario is a garden that is very well protected from wind. If your garden is surrounded by a tall fence or dense vegetation, the wind may not be enough for high pollination rates.

Solution:

In any case, it never hurts to give your plants a little shake every day when the flowers are beginning to open up. This is enough to knock some of the pollen loose from each flower, leading to better pollination and fruit sets.


I hope this article helps you with your tomato flowers. It is always exciting when you see the first batch of tomato flowers forming. Now, you’ll be prepared to help each flower turn into a delicious tomato!

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