Compost Tea Boosts Orchid Growth

Each year, the Southern Zone town of San Isidro de El General hosts its traditional county fair in February.

Like most county fairs, there’s plenty of livestock, show horses, farm machinery and entertainment, such as the corrida de toros (bull run), in which the amateur bullfighters get hurt instead of the bulls.

One of the major highlights of this event that has always captivated me is the orchid exposition, in which local and national orchid growers from around the country show off their best orchids for competition in a dazzling display of natural beauty. There are also plenty of orchids for sale, and collectors can talk shop about orchids.

This year, I had the good fortune to meet Ana Cristina Rodríguez, who grows orchids naturally, without pesticides. I was delighted to talk to her because most growers I have conversed with in the past seemed to believe that growing orchids naturally is out of the question. I always thought that was sort of strange, considering that orchids have spent eons evolving in nature without pesticides, which have only made the scene in the past century at the earliest.

According to Rodríguez, the secret to growing orchids naturally is compost tea, which increases plant growth, provides nutrients to plants and provides beneficial organisms to suppress diseases. Although I have highlighted compost tea for the home garden in this column several times in the past, I thought it would be useful to cover the subject again for our orchid lovers.

For the home gardener, a simple unit can be made using a five-gallon plastic bucket, an aquarium pump, a gang valve to divide the air supply into several streams, three feet of aquarium hose and, of course, good, aged compost.

First, cut and attach three separate pieces of hose at least 12 inches long to the gang valve. Place the gang valve onto the bucket, making sure the hoses reach the bottom, and then connect the aquarium pump. Next, place one gallon of your best compost inside the bucket. Make sure the ends of the hoses are covered.

Now add the water, filling the bucket to within three inches of the top. (If you are using water from a public water source, run the pump and bubble air through the water for at least an hour before adding the compost to the water. This allows any chlorine to evaporate; chlorine can kill beneficial organisms in the tea.) Add one ounce of unsulfured molasses (miel de purga) to provide a food source for the beneficial bacteria. Run the pump for 18 hours starting at midday and finishing with an early morning foliar application before the plant stomata close.

Strain the mixture to prevent the foliar sprayer from clogging. You can dilute or apply the tea full strength depending on your tea production.

Rodríguez also mentioned that a classic hot chile pepper spray is useful in protecting orchid flowers from insect attacks. Blending several hot peppers in a liter of water makes this simple spray. The mix is then strained and sprayed on the orchids. Be careful not to get the spray in your eyes!

Rodríguez added that the National Orchid Show will be held in San José March 17-19 at the Pacific Train Station. If you are an orchid lover, you won’t want to miss this event.