Growing tomatoes is fun, and we grow lots every year. However, it gets difficult when plants develop diseases; the growing season is pretty much over if that disease is deadly. Tomato root rot is one of them.
What is tomato root rot
Tomato root rot is just what the name says, the roots of the tomato plant rot. Usually it is not noticeable before it is too late and the plant dies. A very sad situation. I am sure there are fancy names for the rotting, I’m a simple gardener so I do not need to know if the rotting is a fungus or a bacteria. But if you are into it, here is a good link on tomato problems and diagnostic.
What causes tomato root rot
Tomato root rot occurs when the roots of a tomato plant are constantly wet. Some plants like that, some dislike it, but tomatoes can’t stand it.
Ironically, great gardeners and fancy drip systems get that problem, more lazy gardeners do not know what tomato root rot is.
Also, areas where it is hot and humid (like Florida) have a problem with tomato root rot.
How to prevent tomato root rot
Soil. Tomatoes are heavy feeders and love a light soil with good drainage and lots of compost. If you grow them in a pot or grow bag perlite, sphagnum peat moss and compost are the ideal components for tomato soil (also known as Mel’s Mix from the Square Foot Garden book). But whatever soil you have in the garden, it will be great for tomatoes IF you add lots of compost. If you want to be on the sure side, have your soil tested.
Tomatoes like a soil pH level of 6.0-6.5. To lower the pH use coffee grounds, tea bags, compost, or composted manure. To raise your soil pH level, use wood ash from your fireplace or crushed egg shells. Mix these with your soil.
Water. Tomato plants need to be able to dry in between watering. Careful, I am not talking about irregular watering, which will lead to cracked tomatoes. But watering in intervals, give them a good drink, and let the plants root dry in between.
If you live in a wet area with lots of rain, give your tomatoes protection. A roof, a south-facing wall, or just a plastic bag over the plant in heavy rains can help. In Germany, they sell extra tomato covers for that.
Drip systems are good, but need to be adjusted to the needs of the plant. Constant moisture can lead to problems.
Keep the soil moist but not constantly wet; we mulch our plants with wood chips. Even plants in grow bags or raised beds are mulched with wood chips. The wood takes up excess moisture and gives it back as needed during dry periods.
Tomato variety. Some tomato varieties are more resistant to root rot than others. If you can’t avoid constant wet soil, you might want to look for tomato varieties that are marked as resistant to disease. We prefer heirloom varieties from local growers. After all, they have stood the test of time and are still around.
Keeping the tomato plants pruned, so that no leaves touch the soil can be helpful so the ground around the roots has more airflow.
What to do if you got root rot
Tomato root rot is fatal and contagious. Remove the infected plant immediately, careful not to infect others. Do not plant a new plant in the same spot right away, the soil is infected too. If it happened in a pot or greenhouse remove the soil that was infected, making sure you got rid of the disease. Disinfect your tools and pots. Tomato root rot is not something you want to take lightly.