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Plant Diseases

Most diseases for plants are from fungus, bacteria and virus.

Many diseases are soil born, and they appear in hydroponic systems in contaminated media. There are several ways of ensuring media is clean. One is to use new media. Another is to sterilize the media by drying well in the sun, or using a sterilizing solution such as copper sulfate. In most cases in hydroponics, the media can be sterilized with sun drying and heat. Any sterilizing solutions may cause problems if it leaves any residue in the media. 

There are also disease that are carried by insects. Fighting insect attack by physical barriers and integrated pest management can help to fight against these diseases.

Fungus diseases, such as mildew, can be destroyed by changing the plant environment to hot dry conditions. It is important to have good ventilation in a greenhouse, removing extra water in the air. Also mildews like acid conditions so it helps to spray with an alkaline solution such as baking soda water.

The hydroponic nutrient can help fight diseases or help cause them. A well nourished plant with all trace elements can be healthier and less likely to develop diseases and mildews. They are also more likely to fight off insects.

Old and decaying plant parts - all plant tissues that are dying or dead should be removed from plants and removed from the plant growing area before they attract disease and insects. A good enclosed compost bin near the growing area is a good place to put decaying plant material.

Disease fighting mixtures

Baking Soda Water - Put one teaspoon of baking soda per quart of water. After spraying wait two hours and then spray with pure water to wash off foliage.

Bordeaux mixture - put 8 ounces of copper sulfate to 6 gallons of water. Add 5 ounces of quicklime to ensure the mixture sticks to plants. Mix spray just before spraying and stir often when spraying.

Clear water - a clear water spray over plants and fruits will help control spider mites. It also helps to set fruit on pepper plants. 

Elder leaves tea - to kill mildews Put 1/2 kilo (1 pound) of elder leaves and young shoots in pan with 3.5 liters (6 pints) of water. Boil, then reduce for a simmer for 30 minutes. Strain and use as a spray.

Revised: 1 January 2010
Copyright © 2010 Institute of Simplified Hydroponics