Coffee grounds may help sick sago plants
Coffee grounds may give a boost to sick cycads

Kumari Kelly | Sentinel Staff Writer
March 23, 2008

The gardening remedy seems too simple to be true: Coffee grounds for sick sagos?

"People can't believe it," said Tom Broome, owner of The Cycad Jungle in Polk County and a former president of the International Cycad Society, a group of plant enthusiasts who buy, sell and trade in endangered cycads, a family of plants of which the sago "palm" is a member. "You'd think someone would have thought of this already."

An aggressive pest known as Asian cycad scale has decimated Florida's sago population in recent years, with the telltale powdery look of the scale showing up in backyards and nurseries all over the state. The insect has destroyed entire populations in forests of Guam. Harry P. Leu Gardens in Orlando is taking out nearly all its sagos because the scale problem is so severe.

It has attacked plants from Miami northward, killing as much as 80 percent of the king and queen sago palms in South Florida within a few years of the scale's arrival in the 1990s.

There is no cure for the pest, although University of Florida researchers have traveled the globe looking for predators of the scale, hoping to use a natural method to control the infestations. So far, nothing has worked very well.

Broome, though, says the answer is as close as the nearest Starbucks. After 16 months of experiments using the coffee chain's old grounds, Broome is convinced his coffee method works successfully enough to potentially revive Florida's sago population, as well as the business of some nurseries that in the past relied on their sales. It's cheap, organic, simple and, Broome says, it works.

He hesitates to call it a "cure" because the scale will still exist, but he says the coffee treatments can not only clean an infested sago, but also keep healthy plants from new infestations.

An aggressive pest known as Asian cycad scale has decimated Florida's sago population in recent years, with the telltale powdery look of the scale showing up in backyards and nurseries all over the state. The insect has destroyed entire populations in forests of Guam. Harry P. Leu Gardens in Orlando is taking out nearly all its sagos because the scale problem is so severe.

It has attacked plants from Miami northward, killing as much as 80 percent of the king and queen sago palms in South Florida within a few years of the scale's arrival in the 1990s.

There is no cure for the pest, although University of Florida researchers have traveled the globe looking for predators of the scale, hoping to use a natural method to control the infestations. So far, nothing has worked very well.

Broome, though, says the answer is as close as the nearest Starbucks. After 16 months of experiments using the coffee chain's old grounds, Broome is convinced his coffee method works successfully enough to potentially revive Florida's sago population, as well as the business of some nurseries that in the past relied on their sales. It's cheap, organic, simple and, Broome says, it works.

He hesitates to call it a "cure" because the scale will still exist, but he says the coffee treatments can not only clean an infested sago, but also keep healthy plants from new infestations.

The method is simple: He merely mulches around the base of the plant with fresh grounds and sprinkles some into the center on large plants. For already infected plants, Broome takes the grounds and places them in a mesh sleeve and lowers it into a barrel of water. The sun heats the barrel, creating a "sun tea" effect with the coffee.

He puts the diluted coffee mixture in a spray jug and sprays it on the fronds of the infected plants. The results he reports: healthy scale-free plants.

Ron Cave, a researcher at the UF research facility in Fort Pierce, has seen Broome's report on the coffee and said it was "interesting."

"It certainly opens up new ideas for research but will not dilute our passion for continuing research on biocontrol," he said. "Hopefully, it can all be integrated into an overall pest-management program."

Although Leu Gardens director Robert Bowden said he hadn't heard of the coffee treatment, it can't hurt, he said. Calling Broome a "good friend of the gardens" and the "god of cycads," Bowden said he wanted to hear more but added that the gardens have sago removal on its to-do list. The gardens already use coffee around roses, simply to add organic matter, he said.

"It's not a bad thing," Bowden said about adding coffee. "Will it control scale? I don't know."

Broome said treating a sago every three or four months with the coffee spray and mulch should keep plants scale-free year-round. He performed experiments successfully throughout the life cycle of the scale, which includes a dormant period in winter. The scales, though, aren't gone, only out of sight, he said. They retreat into the root system, and when the weather warms, begin their deadly trek up the trunk of the plant before reaching the fronds.

Broome expanded his experiments and found the use of grounds kept mealybugs off bamboo. He thinks the application could have widespread uses. Coffee grounds are available free daily in Starbucks locations.

"It takes someone a little adventurous to try it," said Broome, who has a degree in finance but has spent years documenting his cycad collections' life cycles and discovering new breeding techniques. He lectures and writes widely on the topic.

"But if they are willing to try, they'll save their plants," Broome said.

Kumari Kelly can be reached at kkelly@orlandosentinel.com or 407-931-5933.