Coffee Grounds Compost

You’ll be over the moon to hear that there are various ways you can benefit your garden with used coffee grounds. Try making coffee grounds compost today!

Coffee grounds carry diverse minerals for plant growth and development – calcium, nitrogen, iron, potassium, magnesium, chromium, and phosphorous. They help plants absorb heavy metals that could contaminate the garden soil. Additionally, coffee grounds act as a magnet for handy worms – great for your garden soil.

Read on to learn all about how to use coffee grounds in compost and when to use them, as well as frequent pitfalls you might encounter when using the coffee grounds in compost.

Let’s begin!

Sources of coffee grounds

You can collect coffee grounds to use as compost from various locations:

First, once you’re done with making coffee, put your coffee grounds in a compost bin. Your own home is the best source of collecting coffee grounds.

Second, talk to the nearby coffee shops and restaurants owners – they offer free coffee grounds. You can visit your nearest Starbucks. They have, in 1995, introduced a program for Grounds for your Garden program, and they offer free bags of used coffee grounds which you can use to use in compost.

If you can’t find free coffee grounds from coffee shops, you can still collect used coffee grounds from your office. To collect coffee grounds from your workstation, add a small bin near the coffee machine and collect free coffee grounds.

Bingo! A free compost for your garden soil.

Coffee grounds in compost

Coffee grounds in compost works like magic for your garden plant’s health.

There are two types of compost material: Green and brown.

At first glance, coffee grounds might appear to be brown compost, but in compost jargon they are green.

Being green compost material, coffee grounds are high in nitrogen content – approximately 1.4% nitrogen by biomass. That’s a lot of nitrogen for your garden plant’s growth and development. Besides nitrogen, they contain magnesium, calcium, potassium, and other trace elements.

Not only the coffee grounds but also coffee filters constitute green compost material. Before adding coffee grounds and filters as compost, it’s essential to balance it with the brown compost. To do so, mix your coffee grounds and filters with leaves and newspaper in a perfect 4 to 1 ratio. This mixing makes your compost perfect for your plant health.

Remember, too much green mass in your compost will give off odor and smell.  

ingredients for coffee face scrub and candles on wood background

How to use coffee grounds in compost?

  • Directly on the soil, spread the coffee grounds. Incorporate the seeds into the soil. If allowed to dry out, they can repel water in the same manner that dried peat moss can.
  • Cover with leaves, compost, or bark mulch after spreading on the soil.
  • Layer the components in the compost pile by using 1/3 leaves, 1/3 fresh grass clippings, and 1/3 coffee grounds.
  • As part of a static compost pile, add coffee grounds, being sure to always include an equal amount of a carbon source, such as shredded paper or dried leaves. Mix everything up thoroughly.

But remember, coffee grounds alone can’t be used as nitrogen fertilizer.

A test was performed at the GrassRoots Garden in Eugene, where the coffee grounds were intermixed with the potting soil at the 1:4 ratio and applied to the lettuce fields. 

To their surprise, lettuce seeds grown in mixed potting soil with the coffee grounds showcased a poor rate of germination and slow growth to the lettuce seeds grown in potting soil without coffee grounds. 

If you’re using coffee grounds directly into the garden soil, don’t forget to add a natural or synthetic nitrogen source. Coffee grounds alone can’t make any difference for better growth and germination during the first year. 

Further, in another research, it was found out that the “coffee grounds are useful to enhance long term crop growth, short-duration weed control, and soil improvement in agricultural fields by considering the inhibitory effects on the plant growth for half year after the application.”

Coffee grounds as fertilizer

Now, you’ve used coffee grounds under your fingertips. Why don’t we put them to some other good use?

You’ll be glad to know that you can add used coffee grounds as fertilizers.

First, you can add coffee grounds directly to your garden soil as fertilizers.

Second, you can mix the coffee grounds with the top two inches layer of the soil, or in another way, sprinkle the coffee grounds over the garden surface. Both methods work pretty well.

In addition to being a good nitrogen source, the used coffee grounds are close to pH neutral. So, don’t worry they don’t pose any potential problem in decreasing or increasing the acidity of the soil.

It’s equally important to avoid using high doses of used coffee grounds or stocking or piling them. When used in larger amounts, “the small particles can lock together, creating a water-resistant barrier in your garden.”

Uniquely, used coffee grounds can work as liquid fertilizers. Add two cups of used coffee grounds to a six-gallon water bucket. Mix them well, let the used coffee grounds work overnight and use them as liquid fertilizers for your outdoor or indoor gardens.

Further, used coffee grounds work perfectly as a foliar spray. You can spray the liquid coffee ground fertilizers onto the leaves directly.

Benefits of using used coffee grounds in compost

Although there are many benefits of using coffee grounds in compost, but we will limit our study to some top benefits of using coffee grounds in compost:

  • First and foremost, coffee grounds can enrich your plants with nitrogen.
  • Next, they are close to PH neutral. So, they don’t pose any threat to soil acidity or alkalinity. They can boost plants’ performance many folds. 
  • According to the reports of Oregon State University, coffee grounds compost can improve soil tilth or structure.
  • Moreover, coffee grounds can ripple snails and slugs from your garden soil.

coffee bean compost isolated on white background

Can you put too much coffee grounds in compost?

If you want to hear a clear-cut answer, then it’s a big no. Master gardener – Kit Smit – has on many occasions warned us about putting too many coffee grounds in compost. It’s because coffee grounds are a little bit acidic in nature. Putting too much coffee grounds in compost can drop the soil acidity considerably. Less soil acidity can limit the growth of garden plants and even may kill them. Additionally, putting too many coffee grounds pose a threat to the beneficial thriving bacteria and other microbes. These microbes play a vital role in maintaining the soil ecosystem of your garden.

What plants do not like coffee grounds?

There are some garden plants that do not like coffee grounds in their root zone. Some notable examples include asparagus, fern, Chinese mustard, Italian ryegrass, century plant, lavender, pothos, orchids, sago palm, yucca, and rosemary. 

Are coffee grounds brown compost?

Once again, the answer is no! Coffee grounds are not included in  brown compost. To disguise you, they may look brown. In reality, coffee grounds are actually green compost material.

How long do coffee grounds take to decompose?

Coffee grounds take three to four months or more to decompose, depending on the soil microbial activity and health. The more microbial activity of the soil, the more quickly coffee grounds decompose. 

brown bag of coffee grounds and sprinkled coffee beans on light wood background

Other gardening articles:

  1. Dark Colored Vegetables For The Garden
  2. How To Grow Ginger Organically
  3. How To Grow Green Onion
  4. Winterizing Raised Garden Beds
  5. Easy Fruits And Vegetables To Grow

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