Coffee grounds for indoor plants are a controversial topic among experts. While coffee grounds can be very beneficial when used properly, they can be detrimental to your houseplants if you’re not careful.
Some commonly chosen ways to add coffee grounds to foliage are sprinkling onto the top of the soil, composting, liquid composting, and mixing into potting soil. However, the best options always include creating a type of compost with old coffee grounds.
Let’s discuss further the good and the bad of using coffee grounds for indoor plants.
When coffee grounds are added to soil and appropriately used, they will significantly benefit plant growth and nutritional goals.
Coffee grounds contain nitrogen, approximately 1.45 percent to be exact. Also full of other trace minerals such as magnesium, calcium, and potassium. Studies show that using grounds as a slow-releasing fertilizer can help get the needed nutrients to your plants more steadily over time than in a short burst.
Adding this extra boost to your fertilizer will not only provide nutrients but is also a natural pesticide. Coffee grounds deter snails and slugs. These grounds, even though small, are abrasive to these slow-moving, slithering creatures.
Water retention is a benefit of adding coffee grounds while being careful not to overwater; sometimes better water retention can mean needing to remember to water less often. If there were a lazy person’s guide to gardening, this tip would be there.
While coffee grounds impressively boost growth by providing nutrients and keeping some unwanted pests away, there are drawbacks.
Plants can become nutrient hogs. Meaning, coffee grounds can cause some plants to halt in growth completely. One plant may soak up all the nutrients while the others around it suffer. Stopping other plant growth can be great for outdoor gardens to keep weeds at bay as long as plants have plenty of spacing. Yet, when indoors, weeds are not as much of a problem and killing one plant to have the other flourish defeats the reason for adding in beneficial nutrients. If you decide to use coffee grounds for indoor plants, be sure to have them in separate pots or provide plenty of space if sharing potting soil.
Coffee grounds are acid-based and benefit acidic plants most. Acidic ph plants that love and thrive on coffee grounds include roses, blueberries, cabbage, hollies, radishes, azaleas, carrots, rhododendrons, and every type of lily.
Basic and neutral soil-loving plants are not big fans of having coffee grounds added into their space. If not careful and monitoring ph levels, this shift in the soil can cause plants to wilt quickly.
Tomatoes, Alfalfa, and Cloves are well-known top three plants to never add in grounds.
There are several different ways to add coffee grounds into a plant’s soil. Some of these ways are better than others.
Top four ways to add coffee grounds into plants potting soil:
Add grounds into your composting cans. Mixing your coffee grounds into your compost that you’ll eventually add to your fertilizer is the best way to reap the benefits without overdoing it.
Top of Soil
Some believe that adding coffee grounds to the top layer of your potting soil is the way to go. Proceed with caution when using this method. Since coffee is very acidic, it can be too potent this way, causing more harm than good. If you decide this is best, do not spread more than ½ inch layer directly onto the soil. Layers too thick can create a barrier making it hard for air and water to pass. This creates issues because it will prevent nutrients from accessing the plant’s roots and create a breeding ground for fungal organisms.
Mixing coffee grounds into plants’ soil is better than coating the surface layer, while still not the best option. Mixing ground into the dirt will increase soil ph and provide mineral benefits yet, will not create a barrier that can harm plants. Since coffee grounds can prevent proper drainage, try using a sand or perlite potting mix to help balance out water retention.
Liquifying compost is an excellent alternative to regular composting. If you want to gain the benefits of coffee grounds but opt not to add them directly to the soil, you can liquefy the grounds and use that compost to water your foliage. This option can provide all the wanted nutrients and minerals without overdoing it.
Creating compost with coffee ground additives, whether liquid or solid, is the safest option for indoor greenery.
Creating compost is a simple strategy. Learn how to make compost the right way.
Liquid compost can be achieved by mixing one part coffee grounds with four parts water and allowing this mixture to soak for about two weeks while stirring occasionally. Liquified compost is used just like you would typically water your plants, but instead of using plain water, use the coffee ground compost mixture.
Solid compost is already a normal habit for many people. It is done by adding kitchen scraps like banana peels, eggshells, tea bags, old vegetables, fruit scraps, and leaves to a usually metal bin. If you already do this, just throw in those coffee grounds, let the organic materials decompose, and break down your compost material. If creating plant compost is new for you, it may seem strange at first to keep kitchen scraps, but soon it will become second nature, and your foliage will thank you.
Did you know that most house plants originate in tropical climates?
These tropical plants thrive in their natural habitats because most of their nutrition comes from decaying organic materials produced by vegetation around them.
At times indoor gardeners will complain that compost in the home does smell. However, this smell does dissipate quickly. When adding compost to fresh soil and mixing it into your houseplant, it is suggested to leave windows open for a little bit to help the smell fade quicker.
A downside to notate when using coffee grounds is that they are very toxic to cats or dogs. Ensure soil with coffee ground additives is kept out of reach from furry family members.
When appropriately used, coffee grounds for indoor plants can boost the nutrition plants crave and give you the luscious greenery and tastier vegetation you aim to achieve.
FAQs for Using Coffee Grounds for Indoor Plants
Personal preference will dictate this choice. Liquid and solid compost are both great options to add to potting soil.
Yes. Coffee grounds are toxic to pets. Cats and dogs cannot metabolize the caffeine in coffee the way humans do. Caffeine in dogs and cats can cause racing hearts, seizures, and organ failure.
Yes, if not used correctly and with the correct plant type. Coffee grounds are best when added to plants that do well with acidic bases. If tomatoes are given coffee grounds, they would likely quickly die, being they are base PH thriving plants. Coffee grounds can also retain too much moisture, keep water and oxygen from reaching plants’ roots, become a fungal breeding ground, and prevent other plants from growing.
Why do people consider adding in coffee grounds? Isn’t regular potting soil and plant food enough?
Yes, potting soil and plant food made specifically for your plant type can be enough. Yet, some opt to add coffee for a few reasons. The main reasons being they produce nitrogen, magnesium, calcium, and potassium; plus, they also repel some types of pests like slugs and snails.
There are multiple ways to add coffee grounds to your plants. Research shows that creating compost to add to potting soil is the safest and reaps the most nutritional value.