Combat Stem Rot, Root Rot, Fruit Rot and Yellowing Plants

Fusarium is a fungus that can infect a plant in many different ways. The Fusarium fungus can affect many types of flower and vegetable plants. A Fusarium infection can come from tainted soil, runoff from a nearby infected soil area, or from nematodes, soil invaders that can carry viral, fungal and bacterial infections to the roots of your plants.

Fusarium usually happens because you overwatered your plants, especially when it appears as root rot. You can tell when you have fusarium root rot because your plant's leaves turn yellow, but if you have gotten that far, you may as well throw out the plant because it is probably going to die and might also infect your other plants. If you have a fireplace where you can burn the plant, that would be the best way to avoid getting Fusarium all over your garden. Don't put the Fusarium in a compost mix or you will contaminate the whole thing.

Fusarium happens more in some plants than others. Plants with bulbs are more likely to get root rot. Vegetables that are at risk of Fusarium include leafy vegetables like cabbage, lettuce and spinach, as well as plants that bear fruit like eggplants, melons and peppers, according to "The Organic Gardener's Handbook of Natural Insect and Disease Control" by Barbara W. Ellis and Fern Marshall Bradley. Tomato plants, herb plants and asparagus plants can also get Fusarium.

To keep Fusarium from getting into your plants, use a good soil solution, and don't put old soil from infected plants in your new plant beds. This may seem obvious, but many people do this very thing. If you are re-using planting containers, sterilize those as well. You can sterilize plant pots by washing them in a bleach solution of at least 1 cup bleach to 1 gallon of water and rinsing them thoroughly until they don't smell. Don't try to sanitize soil with the bleach; instead, bake it in an oven bag at 300 degrees until the soil has reached a temperature of 180 for at least 20 minutes. You can measure the temperature of the inside of the soil with the meat thermometer. Be careful to watch out for steam that might escape the oven bag when you puncture it with the thermometer to test soil temperature.

Also, another obvious piece of advice. Let the soil cool to room temperature. Soil that is even too-warm to your touch can kill the roots of your plant. It's best to wait at least a day before trying to use soil you've just baked to sanitize.

If you don't overwater your plants, and you make sure the soil and container are sanitized, you are really unlikely to end up with Fusarium root rot.

References:
The Organic Gardener's Handbook of Natural Insect and Disease Control
by Barbara W. Ellis and Fern Marshall Bradley
Damping-off Diseases
Sterilize Soil by Microwave