Tomatoes Flowering But No Fruit: 8 Causes & How to Fix It
Do you have plenty of tomato flowers but no fruit? Here are some reasons that may happen and what to do to fix the problem.
Every gardener looks forward to picking red tomatoes off the vine, but if you notice a lack of fruit set, you aren’t alone. Sometimes, you’ll find tomatoes flowering but no fruit, which is when your plants create flowers, but the flowers either drop or fail to produce any fruits.
What is wrong?
If your plants are not setting fruit, there is typically a reason behind the problem, and a reason brings a solution. Most of the time, these issues are easy to fix, so don’t get too frustrated.
Tomato plants have complete flowers; they contain male parts and female flowers inside the same flower. Tomato flowers grow in clusters that hang downward, and they are self-pollinating plants. Pollination takes place through movement and vibrations, like when the wind shakes the plants.
Flowers failing to fruit and dropping off the plant are caused by various issues, such as water stress, excessive nitrogen fertilizer, nutrient stress, low humidity levels, and more.
Related: 8 Reasons Your Tomatoes Aren’t Ripening and How to Ripen Them
8 Reasons for Tomatoes Flowering but No Fruit
Let’s dive into the causes and problems your tomato plants may face and why they may result in a lack of fruit.
1. Lack of Pollination
If tomato plants are flowering but not producing fruit, it could be due to a lack of pollination. This can happen if there are not enough pollinators, such as bees, in the area.
Think about how easy it is for pollinating insects to get to your tomato plants. Tomato plants are self-fertile, so they pollinate themselves. However, that doesn’t mean the wind and pollinators don’t help; they surely do!
The presence of pollinators in your garden dramatically improves pollination, helping dislodge the pollen from the stamens from the female parts.
Sometimes, greenhouse or polythene tunnel-grown tomatoes have trouble with pollinators. Think about whether or not pollinating insects have access to your plants. Make sure your doors are open for airflow and allow insects to access your plants.
When your tomato flowers fail to properly pollinate, blossom drop occurs, leading to the flowers dying and dropping off.
2. Temperatures Are Too High
High temperatures can also prevent tomato flowers from producing fruit. When temperatures exceed 90°F (32°C), the pollen can become sterile, resulting in a lack of pollination.
This is also true when the nighttime temperatures don’t go below 75°F. Tomato plants like hot weather, but heat waves and sudden hot spells are not their friends.
Unfortunately, we cannot control Mother Nature and the temperatures, so all you can do is support your plants throughout the high temperatures. Keep your plants well-watered and healthy, so that once the temperatures reach the ideal range, they can increase the production of fruits.
When you experience a heat wave, a garden shade cloth can provide up to 50% more shade to reduce the intensity of the sun. Row covers help with those hot afternoons in the dog days of summer.
3. Water Stress
Water stress, which is the lack of water or too much water, is another factor that causes tomato flowering but no fruit. It is typically the combination of water stress and high temperatures that lead to tomato plants falling to set fruit.
When temperatures get too high, moisture stress is a problem, and if you fail to keep plants well-watered, then your plants will struggle.
On the other side, overwatering tomatoes causes root rot, stopping plant growth entirely. If you put too much water into the soil, it causes the roots to suffocate and shrivel, stopping their ability to uptake nutrients and water. Overwatered tomato plants have yellow or brown leaves, blisters, or bumps on the lower foliage.
Tomato plants should be deeply watered at least once per week, preferably in the morning. If you experience a very hot, windy day, head out in the morning to water, even if you watered two days ago. Tomato plants need at least one inch of water per week.
4. Insufficient Light for Tomato Plants
Tomato plants require a minimum of six to eight hours of direct sunlight each day to produce tomato flowers and fruits. If they are not getting enough light, they may produce flowers but not fruit. Insufficient light also leads to leggy and spindly growth with little to no fruits.
This can happen if the plants are grown in a shady location or if they are crowded by other plants. If your plants don’t get enough sunlight, then you can’t expect your plants to produce as well as you hope.
5. Humidity Levels Too High or Too Low
Don’t forget humidity levels!
Humidity levels are another complication that contributes to tomatoes flowering but no fruit. If you have high humidity levels (or no humidity), it leads to problems.
High humidity levels clog the pollen in the plants, so it won’t be able to drop. On the other hand, dry climates with low humidity levels lead to pollen that fails to stick and rolls right off the plant, leading to poor pollination rates.
Tomato plants require moderate humidity levels to produce fruit; the perfect humidity range is between 40-70%. You can’t do much to change the humidity levels in your climate, but if the levels are too low for good pollination, make sure to give enough water each week.
6. Pests and Diseases
Pests and diseases can also prevent tomato plants from producing fruit. Common pests that affect tomato plants include aphids, whiteflies, and spider mites. These pests can damage the flowers and prevent pollination from occurring.
Diseases such as blossom end rot and blight can also affect fruit production.
7. Nutrient Deficiencies
Tomato plants require a balanced supply of nutrients to produce fruit; soil fertility matters. Are your tomato plants getting the adequate nutrients needed to produce those red tomatoes you want?
If they are not getting enough nutrients, they may produce lots of flowers but not fruit. Common nutrient deficiencies that can affect fruit production include:
- Nitrogen
- Potassium
- Phosphorus
Once the first flowers appear on your plants, reduce the amount of nitrogen you give to your plants and switch to something high in potassium, or potash. Potash increases flower growth and fruit production.
Potassium promotes flower formation and phosphorous increases fruit yields. There are plenty of sources of potassium fertilizer, such as:
- Compost
- Rotted Manures
- Mined Rock Powders
- Hardwood Ash
- Greensand
- Kelp Meal
If you need more phosphorus added to your garden, here are some fertilizers to add to your garden.
- Rock Dust
- Bone Meal
- Fish Bone Meal
- Manure-Based Compost
Related: How to Fertilize Tomato Plants for the BEST Harvest Ever!
8. Excessive Nitrogen Fertilizer
Did you apply fertilizer a few times this growing season? Too much nitrogen fertilizer leads to excess nitrogen, and too much nitrogen increases leafy green vegetative growth and leads to a decrease in the formation of flowers.
Too much nitrogen leads to more green growth, so you may end up with more leaves and stems than flowers and fruits. That causes flower drop and reduces production yields.
Another problem that overfertilizing causes is potassium or magnesium deficiency.
In this case, prevention is the key. You should only give your tomato plants a small amount of nitrogen. Organic fertilizer is ideal because it’s a slow release, reducing the chances of a nitrogen overdose.
How to Increase Tomato Fruit Production
Now, you’re left with a bunch of flowers but no fruits – what you should you do?
Here are some tips for increasing fruit production after tomato flowering.
1. Hand Pollination or Increase Pollination
One of the reasons why tomato plants may be flowering but not producing fruit is due to a lack of pollination. In this case, hand pollination can be an effective solution, or you may simply need to increase the access that insects have to your plants.
To do this, take a small brush or cotton swab and gently transfer pollen from the stamen to the pistil. This will help ensure that the flowers are properly pollinated and increase the chances of fruit production.
Another option is mimic that bee buzzing by lightly shaking the tomato plants. An electric toothbrush creates just the amount of buzz needed to shake loose the pollen.
Tomato plants grown in a greenhouse have reduced access to wind and insects. Make sure the doors are left open so that insects can wander in and out of your plants. You may also want to set up some fans; the air movement will allow for sturdier plant stems, but it also will shake loose the pollen.
Another option is to purchase bumble bees or mason bees from garden stores to increase tomatoes. This is a temporary fix since the insects will eventually find their way out of your garden. However, it can help with the flowers waiting for fruit.
2. Change Your Watering Schedule
Another reason why tomato plants may not be producing fruit is due to irregular watering, or you have an extreme heat wave, leading to a higher demand for water.
Tomatoes need consistent watering to grow and produce fruit. If the soil is too dry, the plant will not produce fruit. On the other hand, if the soil is too wet, the plant may also stop producing fruit. To prevent this, make sure to water the plant regularly and avoid overwatering.
Another trick to help with water stress is to use a thick layer of mulch, around two to four inches thick, around the plant. Mulch preserves soil moisture and reduces water loss from around the soil surface.
3. Fertilizer Application
Tomato plants require a balanced fertilizer to produce fruit. If the plant is not producing fruit, it may be due to a lack of nutrients or nutrient imbalance.
In this case, applying fertilizer can be a solution. However, it is important to use the right type and amount of fertilizer. Too much fertilizer can damage the plant and reduce fruit production.
A balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium can help promote healthy growth and increase fruit production. Look for slow-release, organic fertilizers; synthetic fertilizers have high levels of nitrogen, which further causes fruiting problems.
In summary, hand pollination, changing your watering schedule, and applying fertilizer can help prevent and treat tomato plants from flowering but not producing fruit. By following these simple steps, you can ensure that your healthy tomato plants produce a bountiful harvest.
Related: 12 Gardening Hacks: Growing More Tomatoes This Year
4. Flush Out the Nitrogen
If you accidentally over-fertilize your tomato plants, try flushing out some of the nitrogen by deeply watering your plants. Another option is to use a carbon-rich mulch around your plants. Doing so neutralizes the soil since too much nitrogen leads to acidic soil.
5. Reduce the Risk of Diseases
Diseases are a big deal, and each tomato pathogen requires unique treatment. Once you identify the disease problem you have, you can take the appropriate action.
However, you can take some steps to create resilient plants from the beginning. Here are some tips to try.
- Make sure the soil is rich and full of organic matter.
- Avoid overwatering your tomatoes. Too much water is more likely to cause diseases or to allow diseases to spread.
- Maintain airflow between your tomato plants with proper planting spacing or pruning the stems for more air movement between the branches.
- Water at the base of your plants rather than overhead irrigation. Drip irrigation or a soaker hose to deliver water to the base.
Conclusion
In conclusion, there are several reasons why tomato plants may flower but fail to produce fruit. These reasons include environmental factors, such as temperature and humidity, as well as cultural practices like fertilization and pruning.
In summary, tomato plants that flower but fail to produce fruit can be frustrating for gardeners. However, by understanding the various factors that can contribute to this problem, gardeners can take steps to encourage fruit set and ensure a bountiful harvest.
