If you don't love coffee yourself, you might consider getting a can of coffee for the plant world. It's time to find out which plants you can use coffee grounds in as a fertilizer, which you shouldn't, and how to find out from the comfort of your home!
Fertilizer is as common in a plant-lovers home as cooking oil is in a chef’s home, but sometimes we want something a little more natural and affordable for our houseplants. Lucky for you, I have an answer: Coffee grounds. Adding coffee grounds to your plants acts as a natural fertilizer without needing to make a compost bin.
There are countless houseplants that like coffee grounds, and in general many plants benefit from natural fertilizers like ground coffee. The plants in question should be acid-loving plants, such as commonly known house plants like peace lilies, jade plants, and weeping fig plants.
However, things can get a bit complicated when you start searching the great wide web for answers. That’s why we’ve rounded everything up and broken the technicalities down for easier understanding.
What Houseplants Benefit From Coffee Grounds and Egg Shells?
Healthline explains in their article covering 16 Creative Uses for Used Coffee Grounds that coffee grounds contain countless nutrients that will assist with plant growth for house plants that like coffee grounds. Nitrogen, calcium, and potassium, among other valuable elements, are key to helping any plant thrive, but those grounds can also protect plants from metal contamination, and attract helpful worms in outdoor plants.
However, you have to use the coffee grounds properly in order to receive the best results! More specifically, using used coffee grounds directly in the soil of the plant. Don’t toss out your coffee grounds after you’ve brewed coffee in the morning, add them to your house plants instead! The difference between used coffee grounds and unused coffee grounds is that used coffee grounds have been activated by the hot water during the brewing process.
They will have a soil texture, and blend well with any potting soil, so you don’t need to worry about it looking strange or standing out, and this boosts plant growth for both indoor plants and outdoor plants. If you don’t like drinking coffee yourself, you can always just brew a small cup and pour the liquid coffee
Now that you know all of this, it’s important to understand that not all plants prefer coffee grounds. Acidic loving plants like coffee grounds, and will act as an organic fertilizer that boosts growth and health, because coffee is also an organic matter considered to be high in acids. Acidic soil, which is also referred to as soil with a low pH (less than seven), is able to handle the acidic levels of the coffee grounds, whereas basic soil, otherwise known as alkaline soil or soil with a high pH (more than seven) is more finicky and requires less acidity in order to grow properly.
The plants listed below are considered to have acidic soil.
Money plants range from a pH level of 6 to 7.5, and are considered to prefer a more neutral soil combination. It would be okay to use coffee grounds with this plant, but be mindful of the amount you give it – especially if it is a small plant.
Snake plants have a pH preference of 5.5 to 7.5. This is the lesser end of the acidic soil measurements and the lower side of neutral soil measurements, so it is okay to sprinkle coffee grounds in the soil to fertilize a snake plant
These climbing ivy plants enjoy slightly acidic soil, with a pH measurement of 6.1 to about 6.5, which is a pretty small margin to watch out for.
Similarly to devil’s ivy, the golden pothos plant also flourishes in the pH range of 6.1 to 6.8. However, there isn’t much to worry about with either of these measurements, as the average potting soil lands in that range of acidity, meaning your golden pothos plants are good to go.
With a pH from 6 to 6.5, spider plant growth intensifies in acidic soil. The spider plant also tends to be more sensitive toward direct light and changes in temperature, so adding coffee grounds might give it the extra boost it needs.
Peace lilies are, indeed, acid loving plants. These houseplants range from a 5.8 level to a 6.5 level of acidity, and therefore are considered to be houseplants that like coffee grounds.
African violets grow best in a less acidic soil, almost neutral, with a pH of 6 to 7. While they will be able to tolerate the acidity of coffee grounds, use coffee grounds for fertilizer in small amounts few and far between.
To get miniature roses to blossom their best, ensure that the pH levels range from 6.7 to 7.4. These flowers are just barely considered to have acidic measurements of soil, and yet can’t quite be considered as acid loving plants.
Cacti are already some of the most low maintenance houseplants you’ll ever own, and the Christmas cactus is no different. This darling plant will thrive with a 5.5 to 6.5 pH measurement, so feel free to strengthen any drooping leaves with a sprinkling of used coffee grounds.
A jade plant, also known to be succulents, is another type of house plant that demands little to no attention and effort to grow. Still, that doesn’t mean they don’t like a little boost during their flowering season, and since they prefer the slightly acidic pH of 6, you can certainly help them achieve this with coffee grounds when you perform the occasional watering.
Of course, there are countless more plants that like coffee grounds as a form of natural fertilizer. If you’re interested in learning more about pH levels, take a look at the Almanac’s article on the Optimum Soil pH Levels for Plants!
What Vegetables Like Coffee Grounds?
Whether you have a garden, are planning one, and the garden is indoor or outdoor, you should know which plants like coffee grounds as a fertilizer made from reusable organic matter! Just as with regular houseplants, you’ll want to look for pH levels lower than 7 for acid loving plants – especially for an indoor garden.
A tomato plant is an excellent plant for acidic soils. Its preferred pH levels are around 5.5 and 6.5.
Carrot pH preferences range from 5.5 to 7, so acidic to an average neutral soil, a sprinkle of used coffee, is best.
You will certainly find with a pH of 4.8 to 6.5, potatoes will turn out to be an avid coffee lover!
As it turns out, broccoli plants grow best in the range of 5.5 to 7 acidity and therefore would love coffee grounds as a boosting fertilizer.
Cucumbers are one of the plants that like coffee, thanks to their tolerance of the acidity as they prefer a pH of 5.5 to 7.
Cabbage is very similar to cucumbers despite it not being a vining vegetable, since its favorite acidic measurements are 5.5 to 7.
Turnip plants also love coffee, so you can spice up their potting mix with a little coffee to reach the acidity levels of 5.5 to a more neutral 7.
Radishes are a specific plant that truly love a low pH, from 4.5 to 5.5, so pouring a nice cup of liquid coffee over your radish garden is definitely a good idea!
Measurements of 6 to 6.8 show that asparagus require a slight acidic environment. As asparagus tend to be very picky, it’s better for you to cater closely to their needs.
Bell peppers will grow in an acidic pH of 5.5 to 6.5, so feel free to add coffee grounds to fertilize for your next picking!
What Plants Don’t Like Coffee Grounds?
Many fruits and flowers tend to be more sensitive to the acidity in low pH soil. Thus, adding coffee grounds in hopes it would act as an organic matter would act as a low-cost organic fertilizer might end up with a seriously unhappy plant. The following plants are commonly kept flowers, fruits, vines, and trees that prefer a less acidic, alkaline soils. Trying to give these plants used coffee grounds could actually stunt plant growth!
Lavender can double as outdoor or indoor plants, so long as they have a pH of about 7 to 8.
Goldenrod truly thrives at the perfectly neutral pH measurement of 7! However, it can survive with small fluctuations. That still doesn’t mean you should add coffee grounds – better safe than sorry
Black-eyed susans are beautiful flowers that love a neutral to slightly basic soil, 7 pH to 7.7 pH.
Daylilies can only handle slightly acidic pH, leaning more toward the basic measurements at around 6.5 to 8.
Much like goldenrod, Easter lilies are neutral loving plants, resting at the pH measurement of 7.
Hostas are a widely known favorite, and tolerate a more neutral pH soil balance. Aim for a 6.8 to 7.8 with access to bright light for long lasting, healthy blooms.
Clematis are beautiful vining flowers, perfect for trellises, and to achieve the best result you should be monitoring pH measurements of 7 to 7.5 with plenty of natural light.
As with the clematis plant, bluebeards thrive in the pH range of 7 to 7.5. These beautiful violet flowers prefer bright light for their bloom and a very slight, mostly neutral soil.
Crocus vernus sits just on the other side of neutral, enjoying a slightly basic pH of 7 to 7.7. This margin is barely bigger than bluebeard and clematis flowers.
Ornamental Cherry Trees
Ornamental cherry trees range from 6.5 pH to 8 pH measurements, so being on the higher end of the pH scale means this plant requires a more basic soil to show the best results during the flowering season.
How Do You Measure pH Levels?
Almanac.com has a great 3 step process to help you measure the pH levels in your soil from home! Their article, How to Test Your Garden Soil, also details two other DIY ways to test pH levels, as well as instructions for take-home pH kits!
Step 1 (Alkaline): Combine two tablespoons of soil and half a cup of vinegar. If the soil begins to fizz, you have alkaline soil!
Step 2 (Acidic): Combine two tablespoons of moist soil and a half a cup of baking soda. If the soil begins to fizz, you have acidic soil!
Step 3 (Neutral): Perform both tests. If the soil doesn’t react to either test, you have neutral soil!
If you don’t feel that your results were accurate, always check at your local gardening centers for take-home pH testing kits! If you’d rather the work be done by a professional, contact someone at your local county office as an inexpensive and accurate alternative.