When you grow tomatoes in your garden, some plants will have their roots showing above ground at the soil surface. This isn’t so mysterious when you dig a little deeper.
So, why are your tomato plant’s roots showing? Shallow watering of tomato plants can cause roots to reach towards the soil surface to find water. Tomato plant roots may also show if the plant is buried too shallow. Wind, rain, watering, or flooding can wash away topsoil, exposing a tomato plant’s roots.
Of course, finding the exact cause will help to treat the problem and prevent it in the future.
In this article, we’ll take a closer look at the main causes of exposed roots on tomato plants. We’ll also offer some suggestions on how to treat tomato plant roots that are showing.
Why Are My Tomato Plant’s Roots Showing?
There are three main reasons that your tomato plant’s roots are showing:
- Shallow Watering
- Shallow Planting
- Soil Erosion
Luckily, there are steps you can take to address each of these causes of exposed roots on your tomato plant..
Shallow Watering Of Your Tomato Plant
Improper watering of a tomato plant will weaken the plant over the course of the growing season. Even worse, the roots of the plant may begin to show at the surface of the soil.
When you provide shallow, frequent watering to a tomato plant, the water never has a chance to go deeper into the soil. It either evaporates in the sun and air, or the plant’s roots quickly absorb the water.
Since there is no water to be found deeper underground, the tomato plant’s roots will not grow any deeper. Instead, the roots will stay shallow or grow up towards the surface of the soil, where there is more water.
Eventually, your tomato plant will become dependent on frequent, shallow watering. At that point, missing a day or two of watering can cause a huge problem for the plant.
If you continue to water frequently after the roots are exposed, the roots are more likely to stay wet for a long time. This can lead to root rot, which can stunt the growth of the tomato plant or even kill it.
Exposed roots are also easier prey for pests that like to feed on plant roots, such as voles. In addition, when your tomato plant’s roots are showing, there is more likely to be a “feast or famine” situation.
Sometimes, the roots get lots of water after a rain. Other times, the roots dry out quickly due to sun and air exposure.
Uneven watering can also lead to blossom end rot, which causes a brown or black spot to develop on the bottom (blossom end) of tomato fruit.
To avoid shallow and exposed roots, you are better off watering your tomato plants deeply and infrequently in the morning. (We will get into more detail on this later).
Your Tomato Plant Was Not Buried Deep Enough
Burying your tomato plant at a shallow depth in the spring is a mistake that can haunt you for the rest of the season.
When your tomato plant is not buried deep enough, the roots can make their way to the surface quickly. This is especially true if you have been providing shallow watering to your plants.
If your tomato plant is having serious trouble finding enough water or nutrients, you may see something strange happen.
At first, bumps will appear on the stem of the plant. Then, the bumps will “sprout” into what look like short, greenish-yellow bristles.
If any of these bristles come into contact with the soil, they will become roots, called adventitious roots.
These adventitious roots will help the tomato plant to draw extra water and nutrients from the soil. Of course, these roots will also show above ground, unless you take steps to bury them under the soil.
Have you ever neglected to tie a tomato plant to a support? If so, you may have seen adventitious roots growing from stem (the part that touched the soil).
You may also see adventitious roots (or their beginning bumps and bristles) on pepper plants. In fact, peppers are related to tomatoes (both are from the nightshade family).
Soil Erosion Due To Wind, Rain, Watering, Or Flooding
Soil erosion can occur in your garden for a variety of reasons:
Soil erosion will be worse if you have lots of bare soil where nothing is growing.
When soil erosion is severe enough, the roots of tomato plants may appear at the surface of the soil. Luckily, there are some steps you can take to prevent soil erosion, including:
- putting up wind barriers
- changing your water management practices (more on this later)
When soil erosion occurs, you will end up losing not only the topsoil in your garden, but also any nutrients that it contains. This makes it more likely that your tomato plants will be unable to find the nutrients they need to grow.
This can happen even if you fertilized carefully at the start of the season.
What To Do If Your Tomato Plant’s Roots Are Showing
We’ve talked about what causes a tomato plant’s roots to show. Now it’s time to do something about it.
Here are some steps to take if the roots of your tomato plant are exposed and visible above the soil surface.
Bury Tomatoes Deep When Planting
One of the most important steps to avoid exposed roots is to bury your tomato plants deep in the ground when spring comes. In fact, you should bury them deeper than you think.
When your tomato seedlings are 6 to 12 inches tall, measure the height of each plant from the bottom of the root ball to the top of the main stem. Then, find the point on the stem 2/3 of the way up the plant (1/3 of the way from the top).
Bury the tomato plant up to this 2/3 point, removing branches and stems below this point if you wish. As always, make sure that you don’t damage the root ball when planting.
If you wish, you can plant each seedling in its own trench, at an angle. For more information, check out my article on why and how to bury tomato plants deep.
Take Steps To Prevent Soil Erosion
Burying your tomato plants deep will not help if you lose lots of topsoil due to erosion. However, if you take a few simple steps, you can prevent most of the soil erosion that will expose your plant’s roots.
Put Up Wind Barriers For Tomato Plants
First of all, put up wind breaks if you experience strong winds or storms in your area. One common and aesthetically pleasing method is to plant hedges along the sides of your garden.
This helps to prevent wind from blowing soil away. A hedgerow also does double duty by preventing soil from washing away in the rain (the roots of the shrubs help to retain soil by holding it in place).
For more information, check out my article on how to protect your plants from wind and storms and my article on how to prevent soil erosion.
Change Watering Practices For Tomato Plants
Second, change your watering practices to prevent excessive water from running through your garden. If you over water with a hose or sprinkler, the soil may wash away from the base of your tomato plants.
Instead, of a hose or sprinkler, consider using a drip irrigation system. Not only will it reduce soil erosion due to over watering, but it will cut down on water waste as well.
Divert Water Away From Tomato Plants
Finally, if your garden is subject to flooding when it rains, then make plans to divert water away from your plants. You can do this by digging trenches and installing pipes.
This will let you direct water away from your garden or towards plants that need more water.
If you find that you continue to have problems with flooding and soggy soil, check out my article on how to improve soil drainage.
Cover Exposed Roots With Soil & Mulch
If your tomato plant’s roots are already showing, then it might be a good idea to cover them. One way to do this is to use some extra topsoil from elsewhere in your garden.
Make sure that the soil is just as good as what you would normally use to grow your tomatoes. This includes adding compost if necessary.
After covering the roots with topsoil, you can take the extra step of putting a layer of mulch over the soil. If the mulch is heavy enough, it will help to prevent the topsoil from being carried away by wind or water.
Even if the mulch is not very heavy, you will lose mulch due to erosion before you lose precious topsoil. You don’t need to use wood chips – there are lots of alternatives to wood mulch.
For example, you can use any of the following as mulch in your garden:
- Grass clippings
- Wood chips
For more information on the pros and cons of each, check out my article on mulch vs. compost.
Water Deeply & Infrequently In The Morning
The goal is for your tomato plant’s roots to grow strong and move downward, deeper into the soil. To encourage this, provide deeper watering at less frequent intervals.
When you water for a longer time period, the water has a chance to soak deeper into the soil. This encourages plant roots to go deeper underground to access more water.
Providing deeper watering in the early morning also prevents the sun from evaporating the water. This gives it a chance to soak into the soil, where a plant’s roots can absorb it.
A larger, more extensive root system means that your tomato plant can draw water from further underground. This helps the plant to survive periods of drought or especially hot days.
Most importantly, it will prevent the plant’s roots from showing above ground, preventing a whole host of other problems for your plant.
Now you have a much better idea of what is causing your tomato plant’s roots to show. You also know how to treat and prevent the problem of exposed roots on your tomato plants.
I hope you found this article helpful – if so, please share it with someone who can use the information.