Here's Why You Should Be Putting Coffee Grounds On Your Lawn

Americans on average drink three cups of coffee a day, according to the National Coffee Association USA. That works out to a lot of coffee grounds, and so the next time you have a cup of joe, instead of simply discarding those grounds, why not use them as an inexpensive, organic alternative to synthetic fertilizers?

Trial-and-error has found that brewed grounds work best, with or without caffeine, but even fresh coffee grounds can be used to feed your lawn approximately once per week. So too can the coffee itself. As Coolabah Turf explains, as a natural fertilizer, coffee contributes to soil health and promotes grass growth. It also provides essential nutrients, aerates the soil, encourages drainage, and repels pests.

Per Burger Farm & Garden Center, coffee grounds are beneficial to plants that favor an acidic environment. The dregs are also a natural weed killer and will discourage the growth of fungi. In contrast to synthetic lawn fertilizers, coffee grounds will not burn a lawn, leech nutrients and minerals from the soil, or contaminate nearby waterways due to ground runoff. Coffee grounds are virtually pH neutral when rinsed, so applying them as a fertilizer will not negatively impact soil acidity. Read on to learn more about how coffee grounds fertilize and why you should consider using them on your lawn.

How do coffee grounds work to fertilize?

According to NC State Extension, fertilizer provides nutrients that some soil may otherwise be lacking. As a natural fertilizer, coffee grounds can serve a similar purpose, and programs like that from the University of Miami's Green U Office of Sustainability are making this point clear. As Green U points out, coffee grounds from Starbucks coffee contain 0.6% potassium, 0.06% phosphorous, and 2.28% nitrogen. There are also hints of copper and magnesium. A trace amount of cadmium occurs in coffee grounds as well.

Earthworms and coffee grounds play a role in stimulating healthy soil. The sod slowly absorbs the coffee remnants when sprinkled on the ground. Worms will consume the coffee grounds and then their castings (droppings) break up the soil and form air spaces, according to Fresh Coffee House. This vermicomposting procedure contributes to soil drainage and lawn growth.

Turf fertilized using coffee grounds should be watered well after they are applied, sufficiently enough to penetrate the top 1 to 2 inches of soil. To prepare brewed grounds before spreading, scatter them on a sheet or tarp and air dry for up to a day. Periodically stir or rake them to expose all the grounds to the sun. The coffee fertilizer can be applied straight or mixed with compost or lime if the lawn is particularly acidic, explains Ground to Ground. Observe a 1 to 4 ratio of coffee grounds to lime if going that route.

Other benefits (and some negatives)

GrowVeg refers to anecdotal evidence of damage caused by coffee grounds, but concludes that the harmful effects of using grounds as fertilizer are due mostly to overuse. It does advise caution when spreading grounds around seeds or seedlings, however; and a caffeine overdose might result in bald spots. In addition to directly contributing to your lawn's health with its benefits to the soil, coffee also repels cats and keeps them from using your garden as a huge litter box. Coffee is also known to deter rabbits, snails, slugs, and some insects.

Although they work as fungi suppressants, coffee grounds are capable of providing an effective medium to grow some mushroom varieties, according to The Lawn Mower Guru. Plants including azaleas, hydrangeas, lilies, and blueberries are also partial to fresh coffee grounds. Per Burger Farm & Garden Center, radishes and carrots will flourish with a coffee fertilizer, but tomatoes will not. The spent coffee is thought to be helpful to lawns where the soil is sandy or clay-filled, and it may absorb harmful contaminants. According to AgriLife Today, coffee as a fertilizer is so effective that it might replace sphagnum peat moss for use on USGA golf courses or other sports fields.

A key attribute of coffee grounds is that they're inexpensive or even free. Bolstering one's personal supply, some coffee shops participate in the Grounds for Your Garden program and will provide, at no charge, at least a 5-pound bag of spent grounds for use on your lawn or in your garden.