IN THE YARD: Coffee grounds

It’s fun to take something found on the Internet stated as stone cold fact and run it by an expert.

This from one of the Green websites: Coffee grounds contain useful amounts of phosphorus and potassium. Grounds are a low-level source of nitrogen and also contain minor amounts of calcium, magnesium, copper and other trace minerals, carbohydrates, sugars, some vitamins and some caffeine, according to Planet Green.

Same source: Coffee grounds are particularly good for acid-loving plants, like tomatoes, roses, azaleas and blueberries, evergreens, camellias, avocados and some fruit trees.

You’ll hear and even read that coffee grounds can be used to change the pH of the soil around hydrangeas to change the color of the blossoms.

Doubtful, said LSU AgCenter horticulturist Dan Gill. “Changing the soil pH is not at all easy,” he said. “It generally takes applications of chemicals like copper sulfate or finely ground sulfur, strongly acid-forming substances, to affect pH that much.”

Even if you’re able to change the pH of soil, over time the original pH will return.

By all means, apply coffee grounds, tea bags, banana peels, apple peels and fresh vegetable scraps to the compost, Gill said.

It stands to reason that spent plants contain some of the minerals and nutrients needed by growing plants, the horticulturist said.

“I can’t say that you will actually see a noticeable benefit to the plants from this, but there is great satisfaction in recycling,” Gill said.

Ed Cullen

Advocate staff writer