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Many coffee-drinkers view an empty pot as a sign to dump the old grounds and make a fresh batch of coffee. But what if you can reuse those grounds to improve your garden? Are you green' enough to try?

Reused coffee grounds are an excellent addition to your compost pile. Placed in the pile with dried leaves or paper, (the brown', or carbon, part of the pile), coffee grounds can be a good supplier of the green', or nitrogen, part of your pile. You should have at least a three to one ratio of brown' to green' compost materials. Coffee grounds generate quite a bit of heat, and that allows for quicker composting. No more than one-fourth of your compost pile should be coffee grounds.

Coffee grounds also contain nutrients that can aid your soil. Besides having a carbon to nitrogen ratio of 20 parts to 1, the grounds contain an NPK (the numbers on the outside of a fertilizer bag) of 2 (nitrogen), 0.3 (phosphorus), and 2 (potassium). Other nutrients include calcium, magnesium, and sulfur. Nitrogen is essential to a plant for leaf development.

Reused grounds have a pH of 6.9, slightly less than a neutral 7. Plants that love acidic soils will thrive with coffee grounds worked into the soil. Quite a few pounds must be worked in to significantly lower the soil pH. Some of the plants that desire this type of soil include pines, evergreens, blueberries, raspberries, roses, azaleas, gardenias, ferns, rhododendrons, lily-of-the-valley, and marigolds.

Coffee grounds can be used as a mulch when combined with something like sawdust or wood chips that will prevent the grounds from forming a crust and preventing water from reaching plant roots.

Probably the most lauded of the reasons for reusing coffee grounds in gardening is that worms seem to love the grounds as a food source. Worm excrement enriches soil, and the soil is aerated by their movement through it.

Some gardeners say they have had success with the use of coffee grounds to repel ants. Controversy exists over claims that slugs and snails are somewhat poisoned by the caffeine level in the grounds.

Fresh coffee grounds may be applied in a thin layer around the base of plants that prefer more acidic soils and worked in with your fingers or with a fork. This prevents mold from developing. Do this before watering or before rain falls so that the nitrogen seeps into the surrounding soil in a time-released fashion.

You may stockpile your used grounds by spreading them on a sheet of newspaper and allowing them to dry. This prevents them from spoiling or fermenting. The dried grounds can be stored in a sealed container and, for top nutritional worth, used within three weeks.

You can make a liquid fertilizer from a half pound of wet grounds and five gallons of water. Allow this mixture to steep for one day before using it on your garden plants.

Reused coffee grounds are a great green' gardening tool!

Learn more about this author, Sandra Petersen.
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