I've had a coffee plant for about a year. It's outside under dappled shade most of the year, except if frost is predicted. What is causing dark blotches on the leaves and a bit of yellowing of the veins? I'm told water with a high mineral content will cause leaching of nutrients and therefore I've been watering with reverse osmosis water and rainwater when available, using very small amounts of Miracle Grow when watering. What am I doing wrong? I can email a photo of the potted plant, but unable to with only this format of communication. I'd appreciate any information you can offer. What kind of fertilizer is best? How often? I have well water, full of minerals and not considered best, that it's more of an acid-loving plant. Any suggestions? Thank you, Gloria Warren 760-749-1113
A bright filtered sunlit area is good for a Coffee plant, soil should be moist, but not soggy.
Nighttime temperatures should be above 60 degrees F, or move the plant indoors.
During the active growing months you can fertilize with a liquid plant fertilizer at half strength, every other week.
Make sure to avoid overhead watering, this can cause leaf spot fungus and disease.
Make sure the plant has air circulation to help avoid fungus diseases.
These links have more information.