Grounds for Optimism

Long before I was old enough to taste that adult morning beverage, coffee, I became a nitrogen delivery system. In other words, I was elected to sprinkle the sediment from the percolator basket around the hosta plants. Recycling before it was fashionable. Unfazed by the caffeine, their huge foliage, continued to expand to gargantuan proportions. The greens were greener, the blues bluer and the variegations more pronounced. We had extreme hosta, years before "extreme" became a buzzword.

Years later, a flowering quince was planted adjacent to the hosta bed and it too, seemed to develop an affinity for coffee grounds. Strong leaf color, steady growth and bountiful blooms (and bumper crops of quince fruits) must be directly attributed to continued applications of that morning sediment - especially since no nutrients, in any other form, were ever offered.

Fast-forward more years than I care to admit, to discover that naturally acidic coffee grounds may have been lowering our already acidic New England soil. And, be advised that hosta, or plantain lily, fed an overabundance of nitrogen, will start to rot. And, consider that the quince was not receiving phosphorus, to boost blossom production. As for the acidity factor, the quince prefers a somewhat acid soil (pH of 3.7 - 6.5), while the hosta requires a sweeter soil, with a pH range of 6.5 -7.5. Still, these plants continued to thrive with their morning coffee.

If you're about to research this topic, brew up an extra pot of coffee. You'll need it. Much of the "evidence" is anecdotal, as is mine. Resources offering scientific results present wildly divergent opinions on the properties and benefits of coffee grounds in the garden. When you "boil down" the available information, you're left with the following salient points and procedures.

Coffee grounds are an organic source of nitrogen, with varying degrees of acidity, according to which expert you believe. Acidifying the soil is a good thing, in areas of high soil alkalinity. Adding a little garden lime or wood ash will neutralize this effect in areas of naturally acidic soil. Augmenting these grounds with rock phosphate and/or colloidal phosphate (more of the necessary calcium) should fulfill the basic needs of most plants.

Enterprising gardeners, carting home huge bags of grounds from the neighborhood coffee shop, are better off adding such large quantities to well-regulated compost piles. And, yes, the filter paper decomposes. Grounds are classified as wet, green, nitrogen-rich material. A balanced pile has alternating layers of green and brown (dry, carbon-rich material, like autumn leaves) materials. Provided with moisture and ventilation, such a pile will quickly yield valuable compost.

When we consider the fact that more gardeners than ever are recycling yard waste into compost, there is cause for rejoicing. With the addition of coffee grounds, our "black-gold" becomes a more valuable commodity, as a soil amendment or as a mulch. In a throw-away society, this is one garden writer who believes we have grounds for optimism!


©Deb Lambert 2007
Photo: Courtesy of Free Images