Colleen Vanderlinden is a specialist in organic gardening. She is the author of Edible Gardening for the Midwest and Vegetable Gardening for the Midwest. Her articles have been featured in publications such as Mother Earth News, Northern Gardener, The Detroit News, and Birds & Blooms.
The response to whether coffee benefits plants is a mix of yes and no. Regularly applying leftover coffee or coffee grounds to your plants is not advisable. In many office environments, plants often receive their only hydration from discarded coffee, which can lead to their decline. However, applying leftover coffee occasionally, such as once a week, and using coffee grounds in moderation can be advantageous.
Continue reading to discover how to utilize leftover coffee or coffee grounds for your houseplants, outdoor greenery, and vegetable garden.
Contents
Frequency of Watering Plants with Coffee
While it may be appealing to use the remnants of your daily coffee for your plants, it’s advisable to limit this practice to once every week to ten days. This recommendation holds true for both indoor and outdoor plants.
If you frequently use coffee or coffee grounds for your plants, monitor their condition carefully. Yellowing leaves or browning tips can indicate that the coffee is increasing the soil’s acidity too much. If you notice these symptoms, reduce your coffee application to once every two to four weeks and observe your plants’ recovery.
Plants and Vegetables That Adore Coffee
In general, plants that thrive in acidic soil benefit from being watered weekly with coffee or from receiving a dusting of coffee grounds. It’s important to note that there is a distinction between plants that favor mildly acidic soil and those that require a more acidic environment. For instance, roses and beans flourish in soil that is slightly acidic to neutral, while blueberries require a significantly more acidic soil to thrive.
Here’s a compilation of indoor and outdoor plants that would appreciate a drink of your leftover coffee:
Houseplants
Herbaceous plants, woody plants, and bushes
Produce and Fruits
Ways to Utilize Remaining Coffee Grounds
You can utilize leftover coffee grounds in two primary ways: by incorporating them into your compost or by mixing them into the soil. While coffee grounds have a nitrogen content of approximately 2 percent, which is relatively low, they can still support plant growth. However, it’s advisable not to apply excessive amounts of coffee grounds as a fertilizer. This is not due to concerns about soil acidity, as coffee grounds do not significantly alter pH levels, but rather because a thick layer can form a barrier that prevents water from penetrating the soil, causing rain or irrigation to simply run off. It’s best to limit the application to a layer no thicker than 1/2 inch in the soil, while the remainder can be added to your compost.
Used coffee grounds serve as a natural repellent for various garden pests, including slugs, snails, and ants. However, there is no proof that they deter deer. While coffee grounds may help keep curious cats away from your garden, their impact on rabbits and other typical garden rodents remains uncertain.
Tip
If you don’t enjoy coffee, remember to save your used tea leaves and tea bags. They serve as excellent soil boosters for plants that thrive in acidic conditions and contribute valuable nutrients to compost heaps.
Ways to Utilize Remaining Liquid Coffee
When utilizing leftover liquid coffee for your plants, it’s advisable to dilute it with additional water, particularly if you enjoy your coffee robust. Depending on how strong your coffee is, you can combine one part coffee with three parts water, or create an equal mixture of coffee and water.
One alternative method for utilizing liquid coffee is by incorporating it into a dry compost heap to enhance its moisture content.
Tip
Utilize only plain black coffee without any flavorings for your plants. Coffee that contains milk, sugar, or other additives is inappropriate for plants and may even be detrimental, much like sugar water.
Is it beneficial to apply coffee grounds to my tomato plants?
It’s not advisable to place coffee grounds directly onto tomato plants. A more effective method is to incorporate them into your compost pile, allowing them to break down naturally.
Is it possible to overdo it with coffee when it comes to plants?
Indeed, using too much coffee or coffee grounds can harm plant development. It’s best to water your plants with diluted coffee just once a week or to apply a light layer of coffee grounds directly to the soil.
Is it possible to simply scatter coffee grounds on my plants?
Certainly! You can distribute them around your plants, but ensure that the layer is thin, ideally no more than half an inch. Avoid using them in garden beds where you are sowing seeds, as coffee grounds can hinder germination and growth.
