Few things take you by surprise like unexpected, unintended plants.
Even better? When a fungus is among us. (Yes, that was necessary!)
Seeing a booming mushroom colony beneath your tomato plant may seem odd or potentially alarming, but you have nothing to worry about.
Wondering how, or why, this happens? Well, it’s all part of Nature’s little plan….
Why Mushrooms Love to Grow Among Your Tomato Plants (and Other Garden Veggies!)
First of all, mushrooms feast upon organic matter. You normally find leaf litter and remnants of wood or brush in your compost or humus mix; this is a favorable mix for mushrooms.
If you use wood shavings with pets and use them as mulch, or if you use wood mulch in your garden, you’ll likely find quite a healthy (and varied) population of mushrooms.
Mushrooms are one of Nature’s greatest decomposers, breaking down wood quickly and efficiently into rich, incredible fertile mushroom compost.
The mushrooms are simply utilizing and breaking down the decaying organic matter that is already in your soil; they’re breaking down and unlocking nutrients for your tomato plants.
Important Factor for Mushroom Growth: Moisture
Mushrooms require a moist environment for growth. If you’re finding lots of mushrooms, there is a lot of moisture surrounding your tomato plants. This is a great time to check for fungal infections among your tomato plants.
Does Mushroom Growth Signal a Potential Problem Among Tomato Plants?
Fungal organisms require moist environments to thrive, therefore some of the worrying infections could thrive in the same conditions that a harmless mushroom can.
To solve a potential fungal infection before it occurs, you need to do three things:
First, stop watering your tomatoes for a while and allow them to dry out. When the soil is dry in the first inch of soil, water plants thoroughly, then allow them to dry out again. This cycle helps to stop fungal growth.
Next, thin your plants and ensure that they have good airflow. If the moisture is able to be trapped among crowded plants, fungal infections could set in and spread rapidly, thriving among the moisture. Remove all leaf litter and debris, as well.
Lastly, prune your tomato plants and remove potentially infected branches. If you notice a branch has yellowing leaves, remove it from the area and burn it.
Mushrooms Thrive In Cool/Slightly Warm Weather
You’ll find that mushrooms tend to be most common during the spring and fall months. They love the wetter weather that these seasons will bring, sure.
However, they also bring cooler and slightly warm temperatures. Mushrooms don’t enjoy the intense heat of summer (too hot and dry), and they do not enjoy cold weather, either.
Take a moment to consider your recent low temperatures, because if they’re dipping below 45*F, your tomato plants might be slightly unhappy. A healthy mushroom population may be telling you to offer your tomato plants a bit of protection tonight!
Mushrooms Don’t Like Direct Light
Mushrooms prefer to grow in shaded areas. They do not require sunlight to grow. This is why you see them thriving in dark places, especially in forests and in crevices.
Mushrooms tend to shrivel up in the sunlight, and you usually see them pop up during the night and early morning hours. Once the heat of the day arrives, the mushrooms have largely disappeared.
Do Mushrooms Mean Your Plant is Suffering from Lack of Light?
If mushrooms are growing prolifically around your tomatoes, it’s quite possible that your tomato plants aren’t receiving enough light. If the plants are shaded by trees, buildings, or are planted on the north facing side of a house, your plants may not be getting enough light.
Tomato plants enjoy full sun (8+ hours of direct light per day), which can be hard to come across in locations that are shaded for part of the day.
If a plant is not receiving enough light, you may notice that:
Plants become leggy or spindly
Plants may fall over easily, or be unable to support themselves, even without developing or ripening fruit.
Plants aren’t flowering or fruiting
Plants seem stunted or slow growing
Ripening fruit may be far smaller than anticipated
How to Get Rid of Mushrooms and Mycelium (If you Really, Really Wanted to…)
Overall, mushrooms won’t hurt your tomato plants.
But, they may not be something you want to see every day.
Perhaps you’re worried your pets or children may eat them, especially if they’re poisonous.
Dry Your Soil
If you have to get rid of mushrooms, I recommend drying out the soil first. Mushrooms generally cannot thrive in dry conditions.
Promote Good Air Flow and Light Penetration
Next, be sure to thin and promote airflow between your plants. This reduces humidity. Thinning your plants allows sunlight to reach the soil, which mushrooms also don’t like.
Cultivating and Disturbing the Soil
Next, try cultivating the soil around your tomato plants, and apply a bit of vinegar to any mycelium that you see.
Vinegar is one of the many natural ways to control fungal organisms, but you have to be careful with it. Too much vinegar too often can make the soil too acidic; in addition, if the vinegar gets on the plant, it can damage or kill the tomato plant. Please use with care.
Chemical Control of Fungal Organisms
Lastly, you could try using a fungicide to help eliminate the mushroom. Mushrooms are the fruiting body of a fungus; they’re only a small part of the entire organism. The mycelium that is living within the organic matter in the soil is the true culprit.
Fungicides can penetrate the soil and treat the problem from within. You may have to reapply it in the future, as new spores could colonize the garden or pots that your grow your tomato plants in. Be sure to keep an eye out for new mycelium growth within the soil and fruiting above the soil (the mushrooms themselves).
There are both organic and non-organic fungicide treatments for garden vegetables; just be sure to purchase only those formulas that are approved for use with food plants that are intended for human and pet consumption.