Last Updated on April 15, 2022 by Admin
You’ve probably heard somewhere that coffee grounds are good for plants and your garden. But are they really?
In this article, I’ll go into detail to answer the question, do plants like coffee grounds? Also, for houseplant growers, more specifically, do indoor plants like coffee grounds?
Do indoor plants like coffee grounds? Not all plants like coffee grounds. Make sure the plant is an acid-loving plant before you apply coffee grounds. You can use coffee grounds as fertilizer, mulch, pesticide or in compost.
Make sure that you limit the amount of coffee grounds or coffee you use because it contains caffeine. Too much caffeine can harm plants.
List of Houseplants That Like Coffee Grounds
The most important thing to check before using coffee grounds in your indoors plant is whether that particular plant likes coffee or not.
The most common mistake many home gardeners make is assume that coffee grounds are beneficial to all plants.
That’s not true.
Instead, they are beneficial to some plants. But are downright harmful to other plants.
Therefore, always make sure that the plant you’ll be applying coffee grounds to likes it.
That’s because coffee is acidic.
More importantly, not all plants like acid. Some prefer a more alkaline environment.
So, you have to choose plants that enjoys acidic conditions.
Also, the kind of coffee grounds you use will affect how acidic the coffee is.
Used coffee grounds are only slightly acidic.
However, unbrewed coffee grounds contain more acid.
Therefore, if you plan on using unbrewed coffee grounds the plant needs to have better tolerance to acidity.
In general, only use coffee grounds on acid-loving plants. These include:
- Peace lilies
- Jade plant
- African violet
- Christmas cactus
- Spider plant
- Maidenhair fern
List of Plants That Don’t Like Coffee Grounds
On the other hand, avoid using coffee grounds on some plants.
Never use fresh coffee grounds on seedling on young plants because they contain more caffeine compared to used coffee grounds.
Excess caffeine will stunt the growth of these plants.
Additionally, coffee ground can also be toxic to some plants. Therefore, avoid using it on the following:
- Sago Palm
- Black Eyed Susan
How to Use Coffee Grounds for Houseplants
The best thing about coffee grounds is that you can use them for houseplants in many different ways.
Below, I’ll go through the different uses of coffee grounds for plants. For each, I’ll explain what you can use the coffee grounds for, how to use and why it helps the plants.
Coffee Grounds Can Be Used as Fertilizer
One of the most common uses of coffee grounds for plants is as fertilizer.
Again, check to make sure first that coffee grounds are well-suited for that specific plant. As long as the plant is acid-loving, the coffee grounds can be used as fertilizer.
To use coffee grounds as fertilizer for plants,
Sprinkle the coffee grounds onto the soil around the plant. Like when applying fertilizer, don’t apply it right over the plant, instead, sprinkle onto the soil.
The soil will absorb it and that’s how the roots take it nutrients.
Coffee grounds work well as fertilizer because they contain nutrients that are beneficial to plant growth.
Additionally, they also attract worms and absorb some heavy metals and excess minerals in the soil which reduces toxicity caused by these items.
However, make sure you know what coffee grounds you’re using.
Don’t use coffee grounds that have milk, cream, sugar or syrup that have been added to it. While the coffee grounds are still effective, these extras increase the risk of mold, fungal disease and pests.
In some cases, the added ingredients and damage or even kill your plant.
From experience using coffee grounds as mulch requires a bit more care.
That’s because you don’t want to use too much since more can actually harm your plant in this case.
Often, mulch is associated with outdoor plants. It helps against moisture loss when the weather gets hot and helps insulate the plant during the colder months.
The good news is that mulch also helps with houseplants although not as many people use it with indoor plants since you can control the environment or move the pot as needed.
However, good mulch can help.
In this case, you can use coffee grounds to add organic matter as well as help with moisture retention.
However, don’t leave a lot of coffee grounds like you would straw or compost.
Instead, a little goes a long way.
That’s because coffee grounds contain caffeine.
Yes, even used coffee grounds still have quite a bit of caffeine left in them. Therefore, I tend to avoid using coffee grounds on seedlings.
With adult plants, a little goes a long way. So, avoid overdoing it.
Coffee Grounds Keep Pests Away
Coffee grounds works well as a pesticide as well. However, it is limited in its use.
To clarify, coffee grounds are more effective for slugs and snails.
Thus, if your plants seem to be prone to these creatures, then creating a barrier or coffee grounds around the plant will help keep them away.
Another way to use coffee grounds is to keep your pets away from toxic plants.
Dogs and cats hate the smell of coffee grounds. In fact, my doggie freaks out from the smell if I place it near her.
So, this is a good way to keep your pets from chewing or ingesting toxic plants indoors.
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Coffee grounds contain nitrogen and carbon. The nitrogen helps with plant growth especially leaf development. Carbon is an important component of compost.
In addition, coffee grounds also contain some magnesium, calcium and potassium, although it lesser amounts.
Nevertheless, they still contribute to making the soil better for your plants.
As such, you can use coffee grounds as compost to help your plant grow.
Alternatively, you can put the coffee grounds into your compost pile and let it decompose along with the other ingredients. The additional carbon and nitrogen will help create better humus.
If you decide to you use coffee grounds as compost directly on your plants, don’t just dump them all in. This is too much for the plant to handle.
Instead, you’ll need to mix in the coffee grounds along with compost.
That said, the better way of using coffee grounds in this case is to put them in the compost pile.
If you do vermicomposting or worm compost instead of regular composting, then you can use coffee grounds in there as well.
Worms like coffee grounds as food.
Again, they cannot take too much at a time due to the acidity of coffee. As such, only add about a cup of coffee grounds into a small worm bin each week.
This will give the worms enough to feed on without overdoing it.
By adding coffee grounds, more worms will be attracted to the soil once you mix the finished compost in.
This is another potential use. But I’m not completely sold here because it may or may not work.
But this is a quick way to use partially leftover coffee.
Make sure to allow the coffee to cool to room temperature. Don’t pour hot coffee on soil.
Also when pouring coffee on your plant, never do so on the plant instead. Try to pour directly on the soil at least a few inches from the plant.
Here, coffee works as a water alternative.
Of course, it does contain the extra nitrogen and a few other minerals.
However, it does contain acid and caffeine as well which aren’t great for the plant. Therefore, if your coffee is heavy on caffeine or you put a lot of coffee and little water in your java, then this is probably not a good idea.
Just skip it.
Also, only use plain black coffee.
Don’t use any coffee with sugar, milk, cream, syrup or other additives added to it. Those extra ingredients will attract pests and other problems.
So, like I said, this option is a bit more iffy.
Tips on Using Coffee Grounds for Plants
Always remember that while coffee and coffee grounds offer some benefits for plants, they can also cause a few potential problems.
As such, you need to weigh the pros and cons before using coffee or coffee grounds on plants indoors or outdoors.
Below, I’ll take you through some of the important tips and reminders when using coffee grounds in plant.
Use Decaffeinated Instead of Caffeinated Coffee If You Have It
If you have a choice or happen to drink decaf instead of caffeinated coffee, then that’s a big plus for your plants.
The reason is that caffeine is on of the ingredients in coffee grounds that can harm your plants.
As such, you want to always be careful when using it directly on indoor plant and your garden. Never apply too many coffee grounds at once.
Instead, always make sure to measure it and control how much you use.
When using coffee grounds as fertilizer, only sprinkle around the plant. Don’t pour a bunch directly onto the soil.
Don’t Overuse Coffee Grounds on Your Plants
One common mistake of using coffee grounds many beginners make is to use it regularly.
Coffee grounds for plants are meant for seldom use.
Therefore, avoid regular usage.
If you’re using coffee grounds as fertilizer, you’ll only want to add it in place of fertilizer. In most cases, that’s once every 4, 6 or 8 weeks. Don’t apply more than that.
When adding coffee grounds to your compost bin, add a bit at a time. Once a week is as much as you need to go. And limit the amount to about a cup for a small compost pile at time.
In most cases, you only including some coffee every time you add to your compost pile. Nothing much more than that.
As a pesticide, only use coffee when the insects start appearing. It is not meant to be a used as a regular application to deter pests.
If you want to pour coffee onto the soil to add moisture, only do so once every 3 to 4 weeks. Avoid doing it on a regular basis or you may see your plant turn brown.
Don’t Add the Coffee Grounds onto the Plant Directly
Like water and fertilizer, never apply coffee or coffee grounds directly on the plant, its leaves or flowers.
Instead, add it onto the soil at least a few inches away from the plant itself.
The goal is to allow the soil to absorb the coffee grounds instead of overwhelming the plant with coffee grounds.
Make Sure the Plant Likes Acidic Soil First
In addition to containing caffeine, coffee is also acidic. Therefore, the first thing you always want to make sure of is that the plant likes acidic environments.
This is not always the case.
As such, using coffee or coffee grounds on some plants can damage them or even kill them.
Thus, this step is always very important.
To check, look up the preferred soil pH of the plant.
If the plant likes soil pH that’s below 7.0, then it prefers acidic soil. This makes coffee grounds a good option for it.
However, the closer its soil pH preference to 7.0 is, the less acid it will tolerate.
Meanwhile a pH of 7.0 is considered neutral.
And pH levels above 7.0 until 14 is considered alkaline or basic (base). So, never apply coffee grounds to plants with soil pH preferences over 7.0.
To give you an idea, plain black coffee has a pH of 5.0 on the pH scale.
While it is not overly acidic, adding a lot can harm a plant especially if its preferred soil pH is 7.0 to 8.0.
In this case, you’ll be better off using water.
Never Pour Hot Coffee onto Your Plants
Plants don’t like hot or cold water. As such, they also don’t do well when hot coffee is poured on them.
This is no doubt burn your plants and cause damage.
Before you pour coffee onto your plants, allow it to cool to room temperature first.
If you’re using coffee grounds, you can let the grounds dry first before applying them.
Do Use Coffee for Making Compost
While you can use coffee grounds directly on your houseplants, a better, more effective way of using coffee is to include it into the compost pile.
Compost piles are made up of kitchen and garden scraps.
These are split into green and brown matter.
Brown matter include things like wood branches, sawdust, newspaper, dry leaves, dry grasses and hay. These are materials rich in carbon.
In contrast, green matter consists of things like food scraps, grass clippings, coffee grounds and tea bags. These are materials rich in nitrogen.
When creating compost, the ratio of brown and green materials is important.
Therefore, make sure to add coffee grounds to the green materials even if they look brown in color.
Always Check and Monitor for Any Changes
When using coffee or coffee grounds on your plants, always monitor to see what happens.
Keep track of when you added the coffee or coffee grounds and what happened after.
Because they have side effects to plants, this will let you decide whether you should use less, can use more or should just avoid using coffee grounds on this particular plant.
Used and Unused Coffee Grounds Both Contain Caffeine
Finally, always remember that both used coffee grounds and unused coffee grounds both contain caffeine.
Many people think that just because you’ve used coffee grounds in today’s cup of coffee that their caffeine content has been depleted.
That’s not the case.
In fact, used coffee grounds still have substantial amounts of caffeine in them which makes them dangerous if you use a lot on your plants.