The Compleat Gardener: Killing Cycad Scale with Coffee Grounds

All photos are by the author and are Copyright
All photos are by the author and are Copyright


In the spring of 2012 my beautiful (before Aulacaspis yasumatsui cycad scale) queen sago (Cycas rumphii) was beautiful no more. All the leaves were covered with scale and the fronds were cascading, dying-like, all around the trunk. I am not showing you what the plant looked like as I am somewhat humiliated at the sight of it. However, if you have one in trouble, you already know what it looked like; even so, you can find pictures of inflected plants on the Internet.

I had tried all that I knew to kill the scale—several kinds of oils, scale insecticides, flea and tick spray, and a strong stream of water. The water treatment worked best, but the plant was suffering badly from year to year. Furthermore, with any of these, I had to treat the plant over and over. Nothing killed the little buggers completely. Searching the Internet I came across an article by Tom Broome who suggested using coffee grounds.

So, with seemingly little to lose, off to Starbucks I went to see if I could get some of their spent grounds. It’s hard to believe, but they are glad to give the grounds to anybody just to get rid of them. Believe me, spent coffee grounds are like gold to us cycad scale victims.

Research on the Internet

The research, whether university scientists or unscientific story tellers (as this work is), runs from completely ignoring coffee to wondering if it might work to exclaiming at the wonderful way it does work. However, a definitive scientific study is still to be completed. Reading the following websites and following up on the citations will give you a good idea of the problem at hand.

Cycads Overview: A surprisingly well done summary with an abridged bibliography of cycads can be found at .

Scale Photos: This site,, shows a fine photo of the scale on the crown of the plant. Additional photos can be found through clicking here.

Cycad Scale Life Cycle: T. J. Weissling and F. W. Howard at the University of Florida, IFAS present a comprehensive overview of the life cycle of Aulacaspis yasumatsui , . The University of Florida, Institute of Food and Agricultural Sciences is one of the world’s eminent research universities delving into plant diseases. Here is reliable information that can be depended upon, but there is nothing about using coffee grounds on cycad scale.

Cycad Scale Life Cycle: The cycad aulacaspis scale, is also a pest of sago palms in south Texas. Carlos E. Bográn, Boris A. Castro and Scott Ludwig, entomology specialists at the University of Texas, offer a fine summary of the life cycle of Aulacaspis yasumatsui in a paper found at https://insects.ta his Texas A&M also has a first class plant research department with reliable information, but here too there is nothing about using coffee grounds for cycad scale.

Coffee, Cycad’s Newest Best Friend: This is the ground breaking article by Tom Broome found in The Cycad Newsletter 30(4) December 2007 Page 46 which describes his experimentation with coffee grounds. Mr. Broome is the owner of The Cycad Jungle, 9330 Bryant Rd, Lakeland, FL 33809, (863) 984-2739. His article shares the methods he uses with grounds and ground sprays. For cycad lovers over the world, this article is worth printing out and keeping close at hand. It can be the saving of your magnificent cycads.

Coffee Grounds Discussion: In a blog Gardening with Georgia of Fairchild Tropical Gardens in Miami, Georgia Tasker rehearsed Broome’s work with coffee grounds, but didn’t add anything scientific to the discussion. Fairchild Gardens has a major collection of cycad species as well as thousands of other wonderful plants and must be visited any time you are in south Florida.

My Simple Coffee Grounds Experiment

My cycads suffered terribly during the winter of 2011/2012. They had been slowly dying over the previous 4 years while I fought the dreaded scale Aulacaspis yasumatsui. I had been able to keep them barely alive using a jet spray from the hose, cleaning leaf to leaf, top side and bottom side. During that winter, two of the younger plants died. I knew something had to be done, or I would lose all of them. So, I decided to cut all of the offending leaves off. A smaller pup that I had been grooming for years had just put out new leaves, and since it was winter in Florida, they didn’t have many scale insects on them so I left those leaves alone. (See photo) The larger mother plant was covered, and I cut off all those leaves. The small pups on the side that I hadn’t cut off I left even though they had scale all over them and several had died.

The way the plant looked as it was first being treated with coffee grounds.
The way the plant looked as it was first being treated with coffee grounds.

About this time I found the article by Tom Broome who used coffee grounds to kill the scale. My wife who drinks coffee and loves Starbucks got me two bags and I used one to make coffee grounds tea, and another to put the pure grounds on the plant.

I made tea and sprayed it on the scale, but I saw no change in the next week or so, and assumed it had done no good. I don’t know if it did or not, but I found out later that I didn’t need the tea anyway.

Finally, feeling somewhat defeated, I started just globing coffee on the crown of the cycad. Starbucks includes the paper filters in the bags of grounds and they come in handy for what we want for our cycads. It’s messy but I took out the papers and intertwined them around the bases of the old leaves in order to help hold the coffee grounds in place. It worked like a charm. Most of the grounds were still there three months later after many waterings and a good rainy season.

These two photos are close ups of the treated plant.
These two photos are close ups of the treated plant.

I did the same for the large pup cutting off some old leaves, but I left the brand new leaves. Then, the crown was packed just like the mother plant.

Photo of major pup after treatment.
Photo of major pup after treatment.

For the mass of smaller pups on the side, I just put grounds in every crevasse I could find. I had some grounds left and just put them on the ground around the base of the plant.

Small pups on the side of main plant.
Small pups on the side of main plant.

A note about infected fronds: The surfaces of the fronds facing directly to the sun seem to be comparatively free of scale even with the undersides virtually covered. I attribute this to their vulnerability to ultraviolet rays, although the scientific proof is probably not available. (If the killing effect of ultraviolet rays interests you, check out this site.)

I let the plant grow new leaves during the 2012 growing season without any interference, and there was little scale, but the leaves were still of the shorter variety we get used to with the scale. By March of 2013 I had my first leaves without any scale. I then packed the crowns with coffee grounds as before preparing the plant for another growing season.

During the summer I had the most growth I have ever had with the resulting beautiful Queen Sago that you see below. Needless to say, I am delighted!

The result!  It is hard to believe that this magnificent plant is the same plant that we started with, but it is.
The result! It is hard to believe that this magnificent plant is the same plant that we started with, but it is.
Even the small pups are putting out beautiful long leaves.
Even the small pups are putting out beautiful long leaves.

I know you might think that I slipped a ringer in on you, but this is the same two plants and pups as we started with. Notice that the fronds are all of the healthy, deep green, shiny, long variety, even those from the pups. The plant was fertilized twice, once in May and again in September, and we had a good rainy season this year.

As you can see from the next two pictures, the scale is completely gone.

The underside of the leaves are free of scale.
The underside of the leaves are free of scale.
A close up of the leaflet show not a sign of scale.
A close up of the leaflet show not a sign of scale.


For me, this little study is enough “proof” that using coffee grounds can be used to protect cycads from the cycad scale Aulacaspis yasumatsui.

I would recommend that botanists consider doing some research on the subject. Furthermore, insecticide researchers might consider looking at the insect killing ingredient in coffee that produces the results noted in this article. I would not be surprised to find more uses for coffee grounds in our quest for happy, healthy plants.

I would be pleased to answer any comments or questions that you might have. Please feel free to email me at or in a message/comments box below.

Acquiring Cycads

There are many kinds of cycads that you can raise, both indoors and outside or in pots and in the ground, but this article deals only with the Sago Palm. There are other cycads that are immune to scale infestation.

You might find cycads at some local nurseries, but up north they probably would not be readily available. If you have a friend who has a mature plant, usually one that is planted in the ground, it might have pups on the side that can be cut off. They are very hardy and usually grow easily.

Growing a cycad in a pot as a bonsai makes a beautiful presentation, although they grow better in the south outdoors in the ground.

Online Site

If you want to obtain a plant online, I would recommend Tom Broome's Cycad Jungle, the man who started the coffee grounds research.

This is probably the best book for an overview of information on cycads. It covers most questions that novices might have in a readable and professional manner. I highly recommend it.

© 2014 Wes Rouse

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paperfacets 16 months ago from La Verne, CA

Love your problem solving with your cycads. On the west coast in Southern California it may be too dry for scale. I had the impression that sago palms were indestructible.

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