Do Calathea Like Coffee Grounds? (+How To Use It Correctly)

Coffee is a popular beverage worldwide, and coffee grounds are famous in the houseplant community for their Nitrogen content. If Calathea is one of the houseplants you own, you might want to know if Calatheas like coffee grounds or not. So, let’s find out!

As a general rule, Coffee grounds are beneficial to Calatheas if they are used correctly. Coffee grounds are rich in nitrogen, and it makes the soil acidic that the calathea plant prefers. However, excessive or incorrect use of coffee ground can burn the leaves leading to wilting of Calathes.

In this article, you’ll understand the right way of using coffee grounds on Calatheas and their benefits and hazards so you can avoid making a mistake. 

Are coffee grounds good for Calathea?

Coffee grounds can do wonders on plants that enjoy acidic soil. Calathea prefers slightly acidic soil, and with the correct use of coffee grounds, your Calathea will be able to draw all the benefits out of them.

People tend to use coffee grounds on their houseplants because these are found in almost all households, and it is better to use them than throw them away.

Coffee grounds have various benefits such as boosting growth, increasing the water retention capacity of the soil, etc.

We will discuss more of these later in this article, but these benefits make coffee grounds suitable for your Calathea plants.

How often to use coffee grounds on my Calathea?

Just because your Calathea likes coffee grounds doesn’t mean you can use them regularly on it. You must also not think of replacing your regular fertilizer with coffee grounds.

Adding coffee grounds once a month to the Calathea should be good enough for the plant. If you think the plant is reacting well, you can add coffee grounds twice a month.

But don’t forget to check your plant’s reaction afterward. If you notice any unusual sight or signs of problems, avoid using coffee grounds twice a month.

Benefits of using coffee grounds

Before finding out how to use coffee grounds on your Calathea, let’s check out their benefits.

Improves retention: Calathea prefers moist soil, so if the soil you use for your Calathea doesn’t have proper retention, you can add coffee grounds to improve the retention.

• Improve drainage: Coffee grounds contain organic matter that helps to improve the drainage of the soil and allows the excess water to run out of the system quickly.
• Provides Nitrogen: People use coffee grounds because of their Nitrogen content. Nitrogen boosts the growth of the Calathea and encourages foliage growth.
• Aerates the soil: Coffee grounds improve the soil texture and allow the roots to breathe and remain healthy by aerating the soil.
• Keeps cats away: If you have a cat as your pet, you might be thinking of ways to keep it away from your Calathea. Coffee grounds alone can do it as cats don’t enjoy the smell of coffee.
• Reduces waste: Coffee grounds are waste matter that is usually dumped in the dustbin. But using it on your Calathea puts it to good use instead of letting it be a waste.

Your Calathea will be able to reap all the benefits only if you use coffee grounds the right way. However, if you don’t use it correctly, you’ll face hazards which I’ll discuss in the next section.

What are the hazards of using coffee grounds?

Coffee grounds can damage your Calathea if you use them the wrong way. Some common hazards of coffee grounds are:

• Stunted root growth: Using coffee grounds in higher quantities can reduce root growth and cause stunted growth in plants, but this happens more on younger plants than mature ones.
• Too much retention: Coffee grounds can improve retention, but too much can lead to excess moisture retention that can cause overwatering, and Calathea doesn’t enjoy being overwatered.
• Harmful for dogs: If you put coffee grounds on the soil and your dog ends up consuming it, you might notice some health issues in your dogs. This is because coffee grounds are not suitable for dogs, especially when they ingest large quantities.
• Stops growth in seedlings: Coffee grounds are not suitable for seedlings, so if you end up giving coffee grounds to your seedlings, you might see no growth in them.
• Too much acidity: If the soil is already acidic, you should not add more coffee grounds to increase acidity. So, before adding coffee grounds, check the soil pH so that the soil doesn’t become too acidic.
• Attracts pests: Coffee grounds can keep snails and slugs away, but they can attract other pests, especially if you directly add them to the soil.
• Fungal diseases: If you add coffee grounds directly to the soil, it will encourage fungal growth, eventually leading to fungal diseases in Calathea.

You can avoid these if you use coffee grounds correctly on your Calathea plant.

What is the best way of using coffee grounds on Calathea?

There are many ways of using coffee grounds on your Calathea plant. Let’s discuss them.

Coffee grounds as a mulch

Mulching is an effective way of adding coffee grounds to your Calathea. You can add a layer of mulch on the coffee grounds instead of just putting coffee grounds on the soil.

You can mix the coffee grounds with organic matter such as bark, wood chips and add them to the soil. This will improve the retention of the soil.

However, you must not add too many coffee grounds as these can stunt your plant’s growth. Add only a small amount of coffee grounds to be on the safe side.

If your area receives less humidity, mulching the plant with coffee grounds can be very beneficial.

Using coffee grounds as compost

Composting is not very different from mulching, but you mix all the ingredients with the soil instead of putting a layer of it on the soil in composting.

Don’t mix coffee grounds alone but add other organic matter along with them. It will ensure that the plant gets all the nutrients evenly.

Coffee grounds will provide Nitrogen, but it doesn’t contain much of the other nutrients the plant needs. While preparing the compost, add 20% coffee grounds along with the other ingredients.

You can add the organic kitchen waste to the compost. 

You can use this and add it to the soil once a month. The soil will remain nutrient-rich, and the coffee grounds will also be used.

Coffee grounds as liquid fertilizer

I was saving the best for the last. Using coffee grounds as a liquid fertilizer is the best way of using coffee grounds.

Follow these steps to make a liquid fertilizer out of your coffee grounds.

• First, pour some water into a container.
• Put it on the gas and let it simmer.
• Turn the gas off and let the water cool down.
• After that, add some coffee grounds.
• Leave this aside for a few days.
• Strain this into a spray bottle, and your liquid fertilizer is ready.

You must let the coffee grounds break down into the water, so don’t skip leaving it aside for some days. Use this on your Calathea every month or once every two months if you want to boost its growth.

Can I water my Calathea with leftover coffee?

You might be thinking of pouring the leftover coffee on your Calathea, but it can go wrong.

• The coffee grounds can have excess caffeine, which can stunt the growth of your Calathea.
• If you pour hot coffee on your Calathea, the plant will get shocked, and the roots will burn.
• You might end up overwatering your Calathea if you start pouring leftover coffee on it.
• Excess coffee can make the soil more acidic than is comfortable for the Calathea.
• If you pour the coffee over the leaves while watering your Calathea with it, you may notice leaf burn.

Final words

Since Calathea prefers slightly acidic soil, it will benefit from coffee grounds. We have mentioned the correct ways of using coffee grounds: mulch, compost, or liquid fertilizer.

There are three things you should avoid:

• Avoid using coffee grounds too frequently or replacing the regular fertilizer with them.
• Avoid putting coffee grounds directly on the soil.
• Avoid using leftover coffee to water your Calathea.

If you use coffee grounds carefully, you will notice more growth in your Calathea. But check the soil before using coffee grounds so that it doesn’t become too acidic.

Also, check your Calathea’s reaction after using coffee grounds on it. If you notice leaf burn or root burn, or any other problems, stop using coffee grounds. You need to reduce the quantity or frequency, or your plant might not enjoy coffee grounds at all.

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Source: NCBI, University of Florida, Wikipedia,  Growing Indoor Plants with Success, Agriculture, and Natural Resources, University of California, Missouri Botanical Garden.