by Aster C. Lilly

Created on: April 24, 2009

Coffee grounds provide an excellent and cheap fertilizer. What most people throw away can be used to improve the consistency and chemical content of your house plant soil. You can even leave the filter with the coffee grounds as most filters can be composted easily.

The first thing to be aware of is that used coffee grounds are slightly acidic. When you have akaline soils, these soils can be poor fertilizers initially. When you add coffee grounds, the ph value of the soil can be lowered, making them more acidic. The plants that enjoy more acidic soil are typically flowering monocots, for example rhododendrons, raspberries, azaleas, lingonberries, grapes, roses, petunias, and many other plants.

If you have any questions regarding your houseplants and their ideal pH, you may want to do some research before you change the pH by adding coffee grounds. Not all plants like an acidic environment, there are many reasons why a plant may not be thriving, coffee grounds should not be used to cure your plant problems.

Coffee grounds also provide an amount of nitrogen. Plants of course need nitrogen in their soil; coffee grounds provide a small amount of nitrogen, but should not be relied on as a source of this essential nutrient. If you truly want to provide a source of nitrogen in your soil, supplement coffee grounds to already nitrogen-rich composts and fertilizers.

Coffee grounds also provide a minimal amount of calcium and phospherous, it's not an ideal candidate for these elements, but it does boost the levels of those elements in the soil.

Some things to avoid: coffee grounds are naturally attractive for mold and other fungi. Be sure to mix the grounds with extra soil; mold can grow on the grounds and spoil your soil. Secondly, coffee grounds can trap water; I advise adding coffee grounds to grainy soil so that water can still pass through and prevent any root loss from clogged pots or flowerbeds.

I suggest adding a pound of used coffee grounds for every ten pounds of mulch or soil compost. This way, you avoid the problems mentioned above, and improve the pH of the compost. The grounds should decompose in a few weeks and become unrecognizable as part of the mulch or soil.

All in all, keep in mind that coffee grounds provide a cheap and effective supplemental fertilizer. While not the ultimate soil that some people purport it to be, coffee grounds can add a small boost to an otherwise fertile soil.
Coffee reduces pH, brings nitrogen, and adds something for your worms to eat. So mix a healthy dose of coffee grounds in with your normal mulch, and you can improve the life of your flowers and berries in your garden.

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