Tomato Plant Flowers Dropping? Increase Blooms & Fruit Set

It’s incredibly frustrating to grow a healthy tomato plant, see it produce lots of yellow blossoms, only to lose them a week later. It doesn’t matter which tomato plant varieties you are growing; this could happen to you!

In this blog post, I will cover the five reasons that your tomato plant flowers may fall off, what you can do about it, and my tips to increase flowering and fruit set.

Edible Nightshades

There is a surprising variety of plants that belong to the family of edible nightshades. These include some popular garden plants, like potatoes, eggplants, peppers, tomatillos, and even goji berries. But the most popular, the undisputed king of the home garden, is the tomato.

I hope you enjoy and utilize this series of blog posts. It is designed to help you grow amazing tomatoes and includes a complete guide on how to grow tomatoes, how to prune tomatoes, how to stake tomatoes, why tomatoes split, and how to grow tomatoes in containers.

Why Tomato Plants Drop Blossoms

Tomato plants begin flowering when they are ready to produce fruit. Each flower has the potential to turn into a delicious tomato if the flower is successfully pollinated.

So why do some tomato flowers drop off without producing fruit? The culprit is likely one of the following:

1. Temperatures are too cold

2. Temperatures are too hot

3. Calcium deficiency

4. Improper pollination

5. Adequate fruit set

How Cold Temperatures Affect Tomato Plant Flowers

Tomatoes are a tropical plant native to South America. This means, in your garden, they may be exposed to weather that is less than ideal for them to grow in, depending on what climate you garden in.

Any temperatures lower than about 45°F will typically result in the majority of your flowers dropping off. That is just too cold for the plant to justify setting fruit. The low temperature causes stress, and the plant tries to conserve energy.

The problem will usually resolve as the weather warms, and you won’t need to do anything. But, if you do want to be proactive, try mulching your plants in the early season! Pro-Tip: I specifically recommend using a black plastic mulch for this application. If you don’t like to use plastic, that’s fine. You can also use woven fabric or other materials, but look for black or dark colored material that will warm the soil and radiate heat up into the canopy of the tomato. This can help raise the temperature so you end up with much better fruit set.

Why Hot Temperatures Cause Blossom Drop

Tomatoes like it warm, but only to a certain extent! Over about 95°F, it is just too hot, and tomatoes can start dropping blossoms.

Again, the plant is trying to conserve energy. It takes a lot of energy and water to set fruit because tomatoes are about 95% water. If a plant knows it cannot produce fruit to maturity, it will simply drop the blossoms or the fruit.

This problem is usually encountered in the late season due to a heat wave. To protect your plants from extreme heat, you can use shade cloth.

Shade cloth is an incredible resource for protecting against the intensity of the sun and keeping plants producing even in the heat. It still allows plants to grow and thrive, keeping them cooler and blocking some of the sun’s energy.

Pro-Tip: It is important to understand shade cloth strengths. In the south, you could probably grow under a permanent 50% shade cloth all season with great success. In the north, you could potentially grow under a permanent 30% shade cloth, but no stronger. I don't recommend using 70% shade cloth permanently, or your plants will suffer from lack of sunlight, but you could use it for a couple of days in an emergency heat wave.

Calcium Deficiency & Tomato Plant Flowers

There is a myth floating around that calcium deficiency causes tomato plants to drop flowers (and the reason why tomatoes split), but that is not entirely true. If your tomato plant shows no signs of blossom end rot, then chances are you do not have a calcium deficiency.

It is true that when a tomato plant is producing flowers, it uses a lot of calcium to form the fruit. If calcium is not available, the plant will drop the flowers.

That being said, calcium is usually an abundant mineral in soil. However, adequate water is required for plants to uptake it because it is immobile without water.

Many gardeners think the solution to blossom drop is adding more calcium to their soil. While this might be true, inconsistent watering is more often than not the culprit that is preventing the plant from uptaking the available calcium!

So if the temperature is between 45° and 95°F, your plant looks healthy, and it is getting blossoms but then dropping them, I recommend watering a little more frequently to keep the soil moist but not soggy. Conditions that alternate from dry to wet, then dry to wet, might be the reason your tomatoes are dropping flowers.

To ensure that your soil always has enough calcium, use compost regularly and top dress with a high-quality fertilizer containing calcium, like Trifecta+. You can also increase calcium with gypsum, egg shells, or crushed garden lime.

Improper Tomato Flower Pollination

Several factors can cause improper tomato flower pollination. First, extreme heat can render the pollen sterile. Second, conditions that are too wet and humid can cause pollen to mold or rot, making it unviable.

The third and most common factor is simply that the flowers didn’t get pollinated. Tomato flowers are known as "perfect flowers,” meaning that they have both male and female components. But they still need something like wind or bees to assist in the process.

If you are having this issue, hand pollination can give you the results you want by increasing your fruit set by up to 50%! All you have to do to hand-pollinate tomato flowers is tap the top of each flower for about 5 to 7 seconds. This mimics a bee or wind, causing vibrations that drop the pollen from the male portion of the flower down into the female portion of the flower.

Adequate Fruit Set

In a perfect world, all the flowers on tomato plants would set fruit. Sometimes, that is the case, but typically, the larger the fruit, the fewer flowers that will set fruit.

Take a cherry tomato plant and a beefsteak tomato plant, for example. You will see a much higher percentage of fruit set on the trusses of flowers that form on the cherry tomato plant.

This is because the water consumption and energy required to yield an individual beefsteak tomato is far greater than a small cherry tomato. The amount of fruit produced stays proportionate to what the plant can support.

The plant doesn’t want to set fruit on an entire truss of tomatoes only to lose the fruit or die because it cannot sustain them. Plus, the weight of multiple large tomatoes on a single truss can cause the truss to snap. One or two tomatoes might be all that the truss can hold, even though there are five flowers.

Pro-Tip: If you are worried that your beautiful cluster of tomatoes will snap the stem, use these tomato saver truss supports! Once only used by professional greenhouse growers, these plastic arch supports fit around the truss and add enough support to safely hold 3 pounds of tomatoes! They’re simple, reusable, and inexpensive.

Tomato Plant Genetics

Now that you better understand how tomato plants react to conditions, you may realize that, just because your tomato plant flowers are dropping off, it doesn’t necessarily mean that you are doing anything wrong. 

Some tomato plant varieties are bred to have a higher percentage of fruit set. The Red Centiflor Tomato is a prime example. Even under poor conditions, this variety will give 10 to 15 times more flowers and fruit than others.

Also, the Trip-L-Crop Tomato is a super productive tomato that will hold a vast majority of fruit on the flowers. Another favorite is the Ace 55 Tomato, which is so productive and almost all the flowers will form fruit as long as you have good pollination.

Ways to Increase Blossom Set

If you want to dig even deeper, watch the video above to learn more about increasing the number of blooms on your tomato plants. In it, I explain four simple tips for increasing blooms and fruit set on your tomatoes.

One more option available to you as a home gardener to help increase blossom set is Tomato & Blossom Set Spray. It is a concentrated, naturally derived plant hormone that, when sprayed on tomato flowers, signals the plant not to prematurely terminate those flowers.

It can dramatically increase your blossom set success rate! To use Tomato & Blossom Set Spray, wait a few days after blossoms open and spray a few squirts on them.