I love tomatoes, so I jumped at the chance to grow some in my own garden at home.
When I prepared to inspect the plants for new tomatoes one morning, I noticed some odd bumps that had formed all along the vines of my tomato creepers. What on earth were these?
In a panic, I rubbed at the bumps, believing these to be about of some fungal infection or perhaps mealybugs that had begun latching to my tomato vines.
However, I discovered this was not what had begun forming on my tomato vines. These bumps were roots!
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White Bumps on Tomato Stems
Tomato vines and stems form white bumps where the roots would have grown. On vines, they become hairy and root when they touch the ground. With tomato bushes, they may get new leaves if the plant is healthy. However, it may sometimes mean the tomato is sick or not getting enough nutrients.
Conditions That Cause White Bumps on Tomato Stems
There are a number of things that can trigger the formation of white bumps on your tomato plant’s stems. Some are normal and you don’t need to concern yourself if these are responsible for the white bumps.
Examples of normal bump formation include a stem or vine that has grown too close to the ground, and it will naturally form these pre-root bumps as the primitive root formation process has been triggered.
However, there are reasons that aren’t beneficial to your tomato plant’s health and these can cause white bumps to form on the roots.
Stress
A plant can become stressed due to any number of reasons, including loss of water, insufficient nutrients, being constantly disturbed by bypassing people and animals, and pest loads that exceed the plant’s normal threshold or ability to recover.
When a tomato plant feels stressed, it will go into an emergency growth spurt due to the release of the hormone auxin. I always think of it as if the plant is trying to grow itself out of trouble.
When this hormone triggers more root growth, it means the tomato plant develops more roots to absorb more nutrients and water, improving the plant’s chances of survival.
Herbicides
Tomatoes are especially susceptible to exposure to herbicides. So if you see white bumps on your tomato stems, it may indicate they have been exposed to a herbicide or other chemical.
White bumps will form, and I often see this accompanied by curled leaves or stunted growth.
Even if your neighbor is using herbicides, a small amount may blow over with the wind or wash into your veggie patch with rainwater.
What to Do About White Bumps on Tomato Stems
In most cases, the white bumps on my tomato stems have proven to be harmless.
However, I also discovered what to do when I see white bumps that indicate my tomato plant isn’t thriving.
Option One: Ground the Bump
If my plant looks a little weak and I see white bumps on the stems or vines of the tomato plant, I may help Mother Nature along and mound up some earth around that bump.
As soon as the tomato stems’ white bumps are in contact with the soil, they will sprout, forming healthy new root systems. This will help your tomato plant regenerate.
Option Two: Fix the Environment
When I noticed my tomato plant began to look somewhat sickly, I also observed there were white bumps on the bottoms of the stems.
Additionally, I also noticed the ground was quite soggy from the large volume of rain we had received that week. The soil was waterlogged, and the tomato plant had developed the white bumps in reaction to this.
To remedy the situation, I added some perlite to the soil, ensuring better drainage. Within no time at all, the white bumps were less noticeable, and my tomato plant began to recover.
Option Three: Guard Against Wilting
Wilting and white bump formation in tomato plants can also point to a bacterial or fungal infection. This means the tomato plant is in distress and may die.
When you see curled leaves, dead and yellow leaves, and your tomato plant is wilting despite the soil not being too arid or too wet, it can point toward the presence of bacterial infection.
The likely culprit is fusarium wilt, which is a bacterial infection and responsible for most wilt among tomato plants.
The best option would then be to purchase some herbicidal poison to remove the bacterial infection. If left untreated, such an infection could easily lead to your tomato plant dying.
Frequently Asked Questions about White Bumps on Tomato Stems
What are the white bumps on tomato stems?
Tomato stems form white bumps when they are stressed or as a precursor to roots being formed when the stems are close to the ground as in tomato vines. Sometimes, these bumps can also be a result of the hormone auxin being released when the plant’s circulation is compromised.
How do white bumps start on tomato stems?
These white bumps will begin as little hairs that grow the length of the tomato stem. When these hairs don’t get the opportunity to grow into roots, they create white bumps instead.
What do you call the white bumps on tomato stems?
The white bumps on tomato stems and vines are known as adventitious roots, meaning they are roots of opportunity. When they are in contact with the ground, these bumps will develop into roots, which can be helpful to anchor a plant.
The Last Bump
When I see white bumps on my tomato plants, I instantly take action, and you should too.
A tomato plant can be very temperamental, and having it put on a show of stress by forming white bumps means it is ill.
So white bumps require action when they are accompanied by other signs of illness such as wilting or blackening of leaves.
Check your tomato plant today to prevent a complete crop loss in the nearby future.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.