Last Updated: April 7, 2023
Over-watering your tomatoes can be a plant killer. Not only can too much water lead to root rot, but it can encourage fungal spores and other pathogens to spread.
In this article, I will share 7 signs that you are over-watering your tomato plants. However, first let’s discuss just how much water you should be giving your tomatoes.
How often should you water tomatoes? Tomato plants like evenly-moist, well-draining soil. This means that the soil should never be soaked for extended periods of time. This can suffocate the root system by pushing out much-needed air from the soil. To water properly, keep the soil moist, but ensure good drainage all season long.
One of the first signs of an over-watered tomato plant is wilting leaves. Unfortunately, this is also a symptom of a thirsty tomato plant, which can certainly be confusing.
However, there is a simple solution: check your soil for moisture content! Dig down about 2-3″ around the base of your tomato plant. If the soil is bone-dry, then you know the problem is lack of water. If it is moist, hold off on watering until the soil is dry.
Drooping tomato leaves are a clear sign that something is wrong. However, don’t just assume it means you are over-watering without doing a bit more detective work first.
Chlorosis (Yellowing Leaves)
Another symptom to look for is discolored leaves, especially yellowing or chlorosis. While yellow leaves can mean a few things, over-watering can certainly lead to this problem.
If you notice yellowing leaves on your tomato plant, there are a few other causes to consider first:
- Nutrient deficiency. Are you fertilizing your tomato plants? If you’re growing in containers, your tomatoes could certainly be in need of nitrogen.
- Natural leaf death. As plant leaves age, they will eventually become less effective at their job. Eventually, the plant decides the leaves are not needed, and they will turn yellow and fall off. This is normal plant behavior, and nothing to worry about!
- Disease. If the yellowing is spotted or seems to be spreading, you may have disease to worry about.
If you can safely rule out the above causes, then yellow leaves may be from too much water. Drowned roots can’t access oxygen, so parts of the plant may begin to turn yellow and die back.
Adventitious Roots On Stems
Tomatoes are very quick to grow roots along any part of their stems. This enables them to re-root wherever the plants come in contact with soil. This makes it incredibly easy to clone tomato plants!
However, if you notice nubby roots along the stem of your tomatoes, you may be overwatering. Moisture is what triggers tomatoes to sprout these “adventitious” roots.
While it could be from over-watering, it may also be from excessive humidity. If you live in a humid environment, these roots can start forming simply from the moisture in the air.
If the soil is overly wet, you would likely see these roots forming near the soil. Consider bottom pruning to increase airflow, and consider reducing watering.
While this symptom is more difficult to diagnose, root rot is a clear sign that a tomato plant has been over-watered. Essentially, roots that sit in water can’t breathe, and so they begin to rot.
Root rot is a serious issue that can eventually lead to a plant’s death.
Not only can root rot be caused by over-watering, but also by diseases such as phytophthora root rot. However, the best way to avoid root rot diseases is to use proper water management.
Thankfully, tomatoes can be saved rather easily from root rot by re-rooting the plants along the main stem. This can give the plant a new connection to the soil and is essentially a form of propagating.
If your plants are diseased, there are of course many possible causes. However, over-watering tomatoes can certainly contribute.
Many fungal and bacterial infections that impact tomatoes prefer humid, wet environments. Therefore, if you are watering too frequently, there may be a higher chance that pathogenic spores will infect your plants.
Not only this, but water is often where spores replicate and spread from one plant to another. So, if your plant leaves are getting wet too often, or you touch your plants after irrigating, you may also be spreading disease.
If a tomato plant is dying, it doesn’t have to mean it is a lost cause! If you have consistently over-watered, you can easily adjust and nurture the plant back to health.
Unfortunately, if it has gotten this far, some damage is already done. Always remove and dead or dying portions of your tomato plants to encourage new, healthy growth.
Again, keep in mind that some leaves will die naturally as they get older. This natural death will usually start at the bottom of the plant where the oldest leaves are.
Last but not least, curling or deformed leaves may indicate an over-watered tomato plant. Excess water in the soil can lead to deformed leaves and unnaturally bent stems.
However, a more common cause of curled leaves is from excessive heat. Tomato leaves will curl to protect themselves from the hot weather. If it has been hot in your area, chances are that this is the culprit.
I hope this article has helped you identify an over-watered plant. Remember, tomato plants like even watering, not too much, not too little. Keep them consistently watered to keep the stress levels low all season long!