We can all agree that coffee is wonderful, but what about all those used grounds that we end up throwing away? It turns out, used coffee grounds can be a wonderful addition to your gardening repertoire. From providing a little extra “oomph” as a fertilizer to keeping the aphids away, coffee has quite a few uses beyond keeping us caffeinated. This article will teach you which plants enjoy the added benefits of coffee, which don’t, how to add coffee to your compost bin, and how to keep the bugs at bay in your garden using your spent grounds.
Which Plants Like Coffee And Which Don’t?
Coffee is an acidic beverage with acidic beans. Because of this, some plants will thrive with the addition of coffee to the soil while others will shrivel. On the spectrum from acidic (low pH) to alkaline (high pH,) most plants trend somewhere in the middle. Some, however, tend toward the extremes. Below is a list of some common garden plants and their soil preferences.
Likes Acidic Soil:
Vegetables: Tomatoes, Broccoli, Turnips, Squash, Corn, Potatoes
Fruits: Blueberries, Blackberries, Grapes, Raspberries
Trees: Evergreens, Willow, Oak, Dogwood
Flowers: Gerbera Daisies, Azaleas, Rhododendrons, Hydrangeas, Daffodils
Likes Alkaline Soil:
Vegetables: Cucumbers, Carrots, Lettuce, Radishes, Herbs
Fruits: Plums, Apples, Peaches, Cherries
Trees: Ash, Beech, Irish Juniper, Maple
Flowers: Carnations, Clematises, Peonies, Poppies, Sunflowers
It is important to keep in mind that even though some plants love acidic soil, this doesn’t mean they’d rather be hydrated with coffee than water. The next sections of this article will outline two proper methods of introducing coffee into your garden.
Coffee & Compost
In the world of compost, coffee is considered a “green” material as opposed to “brown,” despite the color, meaning that coffee grounds are rich in nitrogen. In a perfect compost heap, one should use three- to four-parts “brown” material (dried leaves and newspaper) to one-part “green” material (food scraps and grass cuttings). Coffee should make up no more than 15% the “green” material. This ratio goes for pile composting, turned composting, and vermicomposting alike. In fact, studies show that worms enjoy coffee as well – great news for the vermicomposters out there!
Composting coffee is one of the safer ways to introduce it into your garden if acid-loving plants are grouped together. If not, however, you may consider adding coffee to topsoil as a fertilizer only around acid-loving plants.
Grounds On Top
If your garden features acid-loving plants in close proximity to alkaline-loving plants, you may consider using the grounds on top method when introducing coffee into your garden. Before sprinkling your used grounds, make sure to dry them out completely. Spreading the wet grounds on a cookie sheet and setting in the sun is an effective method. Be sure to rotate the grounds periodically until fully dry.
Once dry, sprinkle an even, thin layer of grounds around the base of your acid-loving plants. Make sure the grounds aren’t too thick on top of the soil. Any more than 1/8 inch of grounds on top of the soil is too much and can slow growth even in acid-loving plants. Once you have sprinkled your grounds, water the plants as usual.
Go Forth and Garden!
Next time you finish your daily cup, consider saving the grounds to reuse in your gar-den. Whether incorporating used grounds into compost or sprinkling them on soil, we’re sure you’ll find recycling coffee helps produce the most beautiful blooms.