Coffee grounds can hasten process in compost heaps

Q My mother is a dedicated recycler. She has begun saving used coffee grounds, but is uncertain about the safety of using them in the garden or/ and compost. I believe they are very acidic. Also, can you help me decide on a potted plant for her on Sunday? I'm looking for beautiful, exotic (if possible) flowers.

A I often find sound, well-researched information from the extension services of various universities, mainly Oregon State and Washington State universities, for horticultural information.

According to the Oregon State University (OSU) Extension Service, coffee grounds are an excellent addition to compost heaps. The nitrogen they contain helps to activate the decomposition process.

The OSU findings also indicate that most of the acid is leached from the ground beans in the brewing process and ends up in the coffee we drink. Shallow layers of coffee grounds can also be mixed or scratched directly into the soil, where they will compost over time “on site,” though years of research at OSU led to a preference for composting them by layering or mixing them into heaps with other materials.

Spread over the ground at any significant depth, coffee grounds will cake over and shed water. Best to mix them in. And anyone who saves coffee grounds in a container as I do, for use later in the garden, knows that wet grounds go mouldy. I store mine in a wide, heatproof, open container so they can be kept at least partly dry.

As for your second question, Martha Washington geraniums have lovely, ruffled leaves and large, stunning blooms in vivid colours and bicolours. That's the plant that immediately came to mind in response to your request for ideas. The plants are not usually hard to find at garden centres at this time.

Another possibility is an orchid. Phalaenopsis are the easiest. For a classic look, a red geranium in a clay pot on a sunny patio shelf or table always pleases.