10 Common Causes of Tomato Plant Not Flowering (How to Fix Them)

We grow tomato plants to enjoy juicy, ripe tomatoes. So it can be frustrating when the plants don’t seem to grow any flowers and fruits. Your tomato plants look healthy but no flowers are growing on them.

Your tomato plants are not flowering because they are not getting the required temperature, water, sunlight, or nutrients. They may not flower because of lack of pruning or too much nitrogen in the soil. Some varieties may flower late and you need to be patient.

I know your pain and have written down all the details to help you understand the problem. Once you know the issue, you can go about fixing it so the plant can start flowering and grow tomatoes.

1. Lack of water

Plants that grow fruits need a lot of water. The common reason why tomato plants are not growing flowers is due to a lack of water.

You may be underwatering the plant because you don’t have the time. Or you may not know when is the right time to water the plant.

The other problem you may have is you are overwatering the plant. And this can also cause a lack of water leading to tomato plant not flowering.

The overwatering will drown the roots in moisture causing problems like root rot. The roots will not be able to supply the required moisture to the plant.

So both underwatering and overwatering can lead to a lack of water reaching the plant.

Solution:

It’s easy to fix the problem of underwatering by increasing the frequency of water you provide.

If the tomato plants are suffering root rot, you need to take the plant out and cut off the roots that are infected. Then replant it in a location that is free from this problem.

I suggest checking the moisture in the soil every morning as you inspect the plant. Tomatoes need moisture in the soil but not too much.

You can stick your finger 1-2 inches in the soil and check if it sticks to the tip of the finger. If the finger comes out dry, that’s a sign you need to water the soil.

Environmental factors can play a role in tomato plant flowering failure. Insufficient light or exposure to cold temperatures can both prevent tomato plants from blooming. Overwatering tomatoes or underwatering tomato plants will lead to stunted growth and fewer flowers. Poor quality soil that lacks essential nutrients may also cause tomato plant flowering failure. – Jacob Thomlinson, Expert landscaping business owner, South Surrey Mowing

2. Insufficient pruning

There may be everything OK for your tomato plant and it still may not flower if you don’t prune it well. The tomato plant may be encouraged to keep growing new suckers and foliage rather than flowers.

The plant cannot spend the energy on growing flowers and fruits and is happy to continue growing more leaves, suckers, and branches.

Once the tomato plant has matured, it’s important to start pruning it. You want to remove any suckers and let the main stem keep growing.

Solution:

You should remove unwanted foliage and branches so the plant can focus on growing flowers. If there are any malformed or dead flowers, you need to prune them as well.

Make sure you don’t prune more than 1/3rd of the tomato plant at a time. You want to avoid stressing the plant due to a lack of foliage.

You can check your tomato plant every week and prune any unwanted parts of the plant. If the suckers are smaller than 2 inches, you can twist and pull them out with your hand.

But if they have grown larger, you’ll need to use a bypass pruner to cut them off the plant. Make sure to sterilize the pruner with rubbing alcohol before using it on the tomato plant.

3. Lack of nutrients

Tomatoes are a heavy feeder plant which means they need plenty of nutrients to be able to flower and grow fruit. If they don’t get the required nutrients, flowers won’t develop.

The macronutrient phosphorus is essential for the tomato plant to develop flowers. So a lack of this nutrient will lead to no flowers on tomato plants.

Solution:

I suggest adding organic compost to the garden soil when preparing it for planting the tomato plant. This will provide nutrients to the soil as well as introduce beneficial organisms to it.

You need to also add fertilizer to the soil every month when the tomato plant is growing. When the plant is young, you can use a balanced fertilizer having an N-P-K value of 10-10-10.

Once the plant has matured and you need it to start flowering, you need to reduce the nitrogen content. So you need to use a fertilizer that is low in nitrogen and high in phosphorus and potassium such as one having N-P-K of 5-10-10.

If you add too much nitrogen to the soil, the tomato plant will be encouraged to grow more foliage rather than flowers and fruits.

I also recommend using organic fertilizer as it is gentle on the soil, plant, and wildlife. Too much chemical fertilizer can also burn the roots and reduce nutrients reaching the tomato plant.

To fix tomato plant flowering failure, pruning tomato plants is often recommended as it encourages more healthy growth and more flowers throughout the season. Adding fertilizer may be necessary if the soil lacks essential minerals or nutrients for tomato plant health. Adjusting temperature settings when possible may be necessary if cold temperatures have been preventing tomato plants from blooming as tomatoes prefer warmer climates with lots of sunlight. – Jacob Thomlinson, Expert landscaping business owner, South Surrey Mowing

4. Poor soil

The tomato plant needs soil that has a pH close to 7. And it has to be soil that has the right balance of sand and clay. If the soil is poor, the plant growth will be poor and you may find flowers are not growing on the plant.

You want the soil to have a good texture that allows moisture and air through it but drains out any excess moisture after a while.

Solution:

I suggest adding organic compost to the soil when you’re preparing the garden for planting tomatoes. The compost helps improve the texture of the soil with its organic matter. It also has beneficial organisms that keep improving soil texture over time.

You can get the soil in your garden tested before planting the tomatoes. You send a few samples of the soil to your Local Extension Service. And they will send you back the results with any required amendments.

If the soil is already poor and the tomato plant is growing in it, you need to start adding the compost so that the soil can improve by the next growing period.

5. Lack of sunlight

Tomatoes are a warm-season plant that needs full sun to grow well. This means at least 6-8 hours of sunlight every day. If they don’t get the required light, it will lead to tomatoes not flowering.

This is something you need to plan before you can plant the tomato plants in your garden. Select a location in the garden that gets the required sunlight.

Solution:

If there are any obstructions such as taller plants or trees, you can try to trim the branches and let more sunlight reach the tomato plants.

If a wall or fence is blocking the light, the only option you have is to move the plant to another location in the garden. If you’re growing the tomato plants in containers, it will be easy to move the container to a good location.

The most common is a lack of sunlight. Tomatoes need at least 8 hours of direct sunlight per day in order to flower and produce fruit. If your tomato plants are not receiving enough sunlight, they will not flower. Another common reason for a lack of flowering is incorrect fertilization. Over-fertilizing can actually cause tomato plants to produce fewer flowers and fewer fruit. Tomatoes need a balanced fertilizer with an equal ratio of nitrogen, phosphorus, and potassium. It is important to follow the directions on the fertilizer package to ensure that you are providing the correct amount of nutrients to your tomato plants. – Tom Monson, Owner of Monson Lawn & Landscaping

6. Lack of heat

Tomatoes need warm weather to grow well. The day temperature between 65 to 75 degrees is ideal to grow tomatoes. If the temperature is too low, the flowers will not bloom.

You want to grow tomatoes when the weather is warm enough. The best time would be spring/summer after the last frost date has passed.

Solution:

If there are a few cool nights that are affecting the plant, you can use a row cover that will help keep the plants warm during the night.

The tomato plant won’t flower even if the temperature gets too high beyond 85 degrees. The plant gets stressed and won’t grow well.

You’ll just need to wait till the weather gets better and reaches the right threshold that the tomato plant prefers.

Tomato plants are happiest when growing in temperatures between 65 degrees F and 78 degrees F. So when temperatures are cooler than that, most tomato plants won’t flower. And when temperatures consistently climb above 80 degrees F, tomato plants stop flowering. So, early in the season, it may be too cold for the plants to flower. And in the heat of summer, flowering usually stops until temperatures cool down in late summer or early fall. – Randy Schultz, Founder, Home Garden and Homestead

7. Lack of growing space

You may grow determinate or indeterminate tomato plants and they may need different space in your garden. If the plants are growing too close to each other, they may not flower due to stress.

If the plants are growing too close to each other, they will compete for nutrients which stunts the growth of the foliage and flowering.

You must get more information about the tomato plant you want to grow. Make sure to plant them keeping enough space in between.

Solution:

If you have already planted the tomatoes and they are stressed due to a lack of space, you need to take one out and plant in another location.

Dig deep around the base of the plant making sure not to damage the roots. Dig a large enough hole at another location that can hold the plant roots. Transplant the plant to this new location and cover the roots well with soil.

Give the tomato plant a good watering but don’t add any fertilizer. Allow the plant a few days to adjust to the new surroundings and prevent plant stress during this time.

8. Diseases

If your tomato plant gets affected by some diseases, they can cause the flowering of the plant to stop. Or they may cause the existing flowers to fall off.

This is a common problem if the tomato plant is suffering from a fungal issue such as botrytis blight.

Solution:

The best solution against fungal issues is to keep your tomato plants away from humid conditions. You should not splash water on the foliage when watering. If you did make sure to wipe the water off the leaves.

Keep sufficient space between the plants so there is plenty of air flowing through the foliage that avoids humid situations.

You can consider growing tomato plants that have resistance to some of the bacterial and viral diseases. This does not ensure they won’t get infected but does improve their chances.

Many pests can harm tomatoes, including aphids and caterpillars, which can defoliate the leaves, limiting the plant’s energy production through photosynthesis.. Blight diseases and Septoria leaf spot can also severely damage leaves. The first thing you should do if your plants are infested with pests or diseases is to identify the specific problem and take immediate action, such as removing the pests manually or using an oil-based solution, such as neem oil, to suffocate them. First of all, it is important to identify the exact cause and determine whether the disease can be treated. If not, the plant must be destroyed so that it does not spread further. – Toshko Vasilev, Expert Gardener, Fantastic Services

9. Lack of pollination

Tomatoes are a self-pollinating plant which means the flowers have both male and female organs sufficient for reproduction and developing seed.

However, this would need some environmental assistance to achieve pollination. Typically, wind or pollinators like bees would help with this process.

But if there is a lack of these environmental factors, the pollination rate could get poor and cause a drop in flowers as the tomato plant comes under stress.

Solution:

I would recommend growing pollinator-friendly plants near the tomato plants to encourage pollinators like bees visiting the flowers.

It’s easy to self-pollinate the tomato flowers by hand as well. You can use a painting brush to collect the pollen and deposit those onto the tomato flowers and encourage pollination.

You can also gently shake the flowers every few days and encourage the pollen to fall into the flower and proceed with pollination.

10. Age of the tomato plant

Sometimes we misunderstand the time it takes for the tomato plant to mature and develop flowers. This will vary depending on the type i.e. determinate or indeterminate. And also on the variety of the tomato you are growing.

Determinate tomato plants will flower at a particular time when the plant has matured. So all flowers will appear on the plant at similar time. Indeterminate tomato plants will have flowering several times during the growing season after the plant has matured.

Solution:

I suggest understanding the tomato variety you are growing whether you start from seed or have bought a transplant.

You should find this information on the seed packet or transplant tag showing when the tomato plant will mature. Usually, this could vary between 30-90 days depending on the variety of tomatoes you are growing.

You can record the date at which you started seeds or bought the transplant and then count the days until maturity. This will help you get an idea if there is a flowering issue or it’s just that you need to be a bit patient for a few more days.

It is possible that your tomato plant is too young and is not at an age yet where it can support blossoms.  Most plants will begin to bloom when they are around 6 to 8 weeks old, with cherry tomato plants blooming from 4 to 6 weeks from the time of seeding. – Krista Green, Founder, Zone 3 Vegetable Gardening