Megan Wild is an experienced gardener who loves planting and pruning flowers all throughout the Spring and Summer. When she’s not coveting the flower bed she’s near, you can find her writing her advice and ideas on her blog, Your Wild Home.
Ever wondered what to do with all those leftover coffee grounds from your cup of morning joe? It turns out the grounds don’t have to be destined for the trash and can serve as a rich sources of essential oils, fatty acids and other nutrients to enrich your soil — be it in the garden or in your potted windowsill plants.
You’re probably wondering what exactly your coffee grounds can do and how you should go about using them. Don’t worry, we’ve answered the burning questions behind gardening with your java below.
What Benefits Lie in Coffee Grounds?
Let’s take a look at the contents of your typical Starbucks coffee grounds. According to a report requested by the magazine Sunset, coffee grounds that Starbucks gave away for free were able to amend soil minerals by 35 percent.
The report also highlighted that coffee grounds substantially boost phosphorus, magnesium, copper and potassium minerals available in the soil, as well as canceling out the need for the addition of most chemical nutrients. Don’t throw out your grounds from your home brew and even consider visiting your local Starbucks for some extra composting material.
It is also important to know that certain plants respond to coffee grounds more positively than others — it’s best for the types that enjoy nitrogen rich environments for spreading their roots. Some examples of these types of coffee-hungry plants include: corn, roses, tomatoes, spinach, azaleas, camellias and rhododendrons.
Another great benefit: Coffee grounds act as a natural pest repellent for your garden. Even just a little bit of your used java will help save vegetables like beets, peas, broccoli, lettuce or beans from squirrels and rabbits. You really can’t go wrong!
How Do You Work Your Grounds Into the Soil?
Again, coffee grounds can’t replace the need for all nutrient additives. You’ll maximize its use, though, if you add another supplemental fertilizer to the soil at the same time. This way, the coffee grounds have time to decompose and release their nutrients back into the soil you are tilling without limiting the plant growth while you wait. The decomposition can take several months, which is why it’s so important to supplement in the meantime.
If you are looking for extra reading material, one great read for gardeners, 1000 Gardening Questions and Answers, has fantastic tips on how to properly use your coffee grounds. For example, they recommend using six or fewer pounds of grounds for each 100 square feet of planting space.
Can You Use It as Mulch?
The answer to this question is, most definitely, yes. However, you need to take care not to exceed a thickness of more than one half of an inch of grounds on the top layer of soil. A thicker layer can become a moisture barrier that limits the entrance and exit of air and humidity in the soil.
Contrary to popular belief, coffee grounds have been found to be not only mildly acidic, but also mildly alkaline at times. As they decompose, the grounds tend to have a close to neutral pH of 7, making them great for use as a sheet mulch around fruit trees, blueberry bushes, cane fruit and currants, as Chef Erica writes on her blog.
If you’re mulching large bits of land — for, say, a fruit tree orchard — you may want to consider looking into transporting all that mulch: Use a utility vehicle ideal for landscaping. It’ll make your gardening days that much more efficient and productive.
Can You Add It to Compost?
Since coffee grounds are rich in nitrogen content, they are a great addition to your backyard compost pile. If you stick to a 1:1 ratio of grounds to leaves or grass clippings, you’ll have an ideal balance to create a great compost mixture. Try to stick to this ratio, as adding too many grounds can have a detrimental effect on your compost.
With the right mixture of coffee in your compost, you’ll not only speed up the decomposition process, but you’ll also yield better, higher quality fertilizer that operates as an antimicrobial agent as well. This great little bonus can prevent certain fungal diseases from forming on plants like tomatoes, cucumbers and beans.
Do Any Plants Respond Negatively to Coffee Grounds?
Most plants that you will work with respond well to the nutrient-rich use of coffee ground compost or mulch. However, this doesn’t mean they all do. In fact, using coffee grounds with some plants can actually harm them by stunting growth or preventing seed germination. So, avoid using coffee ground with plants like asparagus fern, alfalfa, geraniums or white clover. The results won’t be good.
The coffee-ground soil amender is an extremely useful tool for the avid gardener, and a green choice at that. The next time you consider throwing your grounds in the garbage, reconsider how many benefits are waiting to be used by your flowers, vegetables and leafy plants.