San José, Costa Rica, since 1956

Grow your own friendly fungus

Last year I wrote about a very promising development centering around trichoderma, a unique soil organism that has been around for eons, just waiting for us to discover its marvelous attributes (TT, Jan. 29, 2010).

Trichoderma species were identified and reported as common soil fungi back in 1930, but it wasn’t until recently that researchers began to focus on these fungi. When the chemical methyl bromide, which is used to treat a number of plant diseases, was discovered to cause ozone depletion, researchers took another look at trichoderma as a substitute.

Ed Bernhardt

Ed Bernhardt

Trichoderma fungi were termed opportunistic avirulent plant symbionts, meaning that plants become hosts for the beneficial fungi, providing them carbohydrates in return for protection from diseases. Researchers have found trichoderma effective against a wide range of pathogenic organisms, including those causing stem rot (Fusarium spp., Pythium spp. and Rhizoctonia solani), onion rot (Botrytis cinerea and Sclerotium rolfsii) and late blight (Phythopthora), as well as white mold (Sclerotinia).

Costa Rica has also done its fair share of research and development in the use of trichoderma as a biological control for agricultural crops. The fungus is now being used in the tropics to protect a wide range of food crops, including rice, tomatoes, potatoes, cacao and sugarcane.

This year, I obtained a culture of trichoderma and have been inoculating my garden soil and plants with it. I am delighted to report that our garden vegetables have shown a significant improvement in growth and vitality, and particularly our tomatoes have shown much more resistance to leaf diseases during this rainy season. I have also – eureka! – succeeded in cultivating my own batches of trichoderma at home for future use.

The method is relatively easy to do in the kitchen by preparing rice in a pressure cooker and then inoculating it with the fungus when it’s cool. I used quart canning jars filled with 300 grams of rice and 50 milliliters of water. The jars were covered with nylon mesh and placed inside the pressure cooker with 5 centimeters of water in the bottom of the cooker. The batch of jars was cooked for 45 minutes to ensure the rice was cooked and the jars sterilized.

The next day, when the pressure cooker was cool, I opened it and inoculated each jar with 20 mL of liquid trichoderma solution. I placed the jars in a warm place and covered them with a clean kitchen towel. Ten days later, the jars were full of a dark green fungus.

The accompanying photo shows the final product, which can be diluted in water and sprayed on your seed flats, garden soil and compost piles to populate your garden with this superstar of the fungus world.

For more information on how to grow trichoderma for home use, contact me at

Comments are closed.