Question
Hi. I've heard that many people fertilize carnivorous plants with coffee with no bad effects afterwards. My question is could I feed my plants American style medium ground roast coffee as I have only heard people use black ground coffee. Please answer this.

Answer
Hi Daniel,

Quite a few postings have been made on bulletin boards over the past few years touting the wonders of using coffee on carnivorous plants.  I'm going to be the black sheep on this issue.  I tried it a couple times, and have seen unimpressive to no results.  I've also heard from a couple of folks that it may cause problems, especially if used in the winter, since the plants are not growing as much as in summer.  Also, the good results reported have been mostly on Nepenthes, not other cp species.  You are very likely to kill plants like sundews and Venus flytraps since you are essentially applying an organic fertilizer.  In all cases what people were doing is pouring brewed coffee into the soil of plants, not using coffee grounds.

Now, despite my pessimism, I think much more controlled research is in order on this topic.  I would love to see someone set up a proper experiment with controls on this, including using the coffee on regular plants which many have done for decades.  I personally do use coffee grounds in my vegetable garden, but the difference there is the soil has lots of bacteria to break the coffee down and release the nutrients.  CP soil media can be pretty inert.

My bottom line would be it's worth experimenting, but I would only personally used it on plants you're not afraid to loose.  Using coffee on some rare, expensive, slow-growing highland Nepenthes could be a source of heartbreak.  However, trying it on a little $7.00 plant you picked up at a big box store, no problem.

Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com