Is Coffee Grounds Good For Indoor Plants? (Potential Problems+How To Use)

Coffee grounds are easily available in most households because everyone enjoys a good cup of coffee in the mornings. The fact that coffee grounds are easily available makes them popular in the houseplants community.

You can fertilize your indoor plants with coffee grounds. But is it good for them? Let’s find out.

Coffee grounds are suitable for indoor plants because they contain nutrients like nitrogen that help the plant grow faster. However, instead of adding it directly on topsoil, you can make compost, liquid fertilizer, or mulch out of the coffee ground as it helps minimize the side effects.

But there are some don’ts that you should know if you want to use coffee grounds on your plants.

Never add them directly to the soil as they can retain excess moisture and make the soil soggy or increase its acidity drastically that your indoor plant might not enjoy.

This article will explain to you the pros and cons of using coffee grounds, which indoor plants love coffee grounds, and the best ways to use coffee grounds on your indoor plants. Keep reading.

Pros and cons of using coffee grounds

You should be careful while using coffee grounds on your indoor plants. This is because coffee grounds can damage your plants if you don’t use them properly.

But before that, let’s discuss the benefits of using coffee grounds as fertilizer for your indoor plants.

Pros:

1. Coffee grounds are easily available.

This one of the best things about coffee grounds is that they are easily available. Most people like to drink coffee, so they always have coffee grounds in their kitchen.

People don’t do anything with the used coffee grounds other than throwing them away to use them on their indoor plants to fertilize them easily.

Even if you don’t have coffee grounds at your place, you can get some used coffee grounds from your neighbor and use them.

2. Coffee grounds are rich in Nitrogen.

Another reason that makes coffee popular is that it is rich in Nitrogen. Nitrogen is an essential element that indoor plants need for their growth. Coffee grounds provide a lot of Nitrogen to your plants that can boost their growth.

Coffee grounds also contain phosphorous, another essential macronutrient that indoor plants need. Phosphorus helps in photosynthesis, the transformation of sugar and starches, and other internal functions of plants.

Coffee grounds contain micronutrients such as calcium, iron, magnesium, etc., that benefit your houseplants in different ways.

3. Coffee grounds cost less.

If you want a growth-boosting fertilizer at a low cost, you should consider coffee grounds.

Instead of purchasing a fertilizer rich in nitrogen, you can use coffee grounds that will not cost you anything extra.

So, coffee grounds can save you some money that you would have used to buy fertilizers for your plants, making it a very economical option.

4. Coffee grounds are eco-friendly.

Instead of dumping coffee grounds in the garbage, using them on your plants can reduce pollution and benefit your indoor plants.

Coffee grounds are a natural way of fertilizing your indoor plants that reduce synthetic fertilizers that you may buy from the markets.

Cons:

1. Retains excess moisture.

Coffee grounds are great at retaining moisture. Even though this might sound like a good thing, it can become a problem for your indoor plants.

Most indoor plants prefer moist soil, but using coffee grounds can make the soil soggy, the same effect that overwatering has on the plants.

If you use coffee grounds for your indoor plants, you need to ensure that the soil is well-draining and not holding too much moisture. Add perlite to the soil to increase the drainage so that the soil doesn’t go soggy.

Make sure that the pot has drainage holes to drain the excess water fast. If you make sure that the drainage system of your indoor plant is working well, coffee grounds will not harm them.

2. Invites pests.

While coffee grounds can repel pests like wasps and bees, they can attract pests like ants, slugs, snails, etc.

Adding coffee grounds to the soil, the chances of pest infestation increases. So using coffee grounds as compost is the best way to keep the pests away.

3. Encourage fungal growth.

Fungal growth can be highly harmful to the soil and the houseplants. And adding coffee grounds directly to the soil encourages fungal growth. 

Coffee grounds retain more moisture, creating the ideal environment for fungal growth. Use coffee grounds as compost or liquid fertilizer to reduce the chances of fungal growth.

4. Reduces growth.

Although coffee grounds encourage more growth, they can do the opposite in young plants and seedlings. Again, the reason behind this is the usage of coffee grounds directly to the soil.

Using compost or liquid fertilizer can help combat this problem, or you might skip using coffee grounds on your young plants and use them only on the mature ones.

How do you use coffee grounds on houseplants?

There are different ways of using coffee grounds on your indoor plants but adding them directly to the soil is not an option as this brings all the problems.

So, let’s find out some tried and tested methods of using coffee grounds on your houseplants to get the benefits out of them without causing any damage to your plants.

Coffee grounds as compost

Composting is considered the best way of using coffee grounds on indoor plants. You can add the used coffee grounds to your compost pile, wait for few days and then give it to your indoor plants.

The compost contains browns and greens. Coffee grounds are greens as they are rich in Nitrogen, while elements like dried leaves are browns as these are high in carbon.

Make sure to maintain a ratio of 3:1 of browns to greens while making the compost.

You can add the compost:

• While repotting the plant.
• As a top layer on the soil.
• Mix it with the top inches of the soil.

Indoor plants do not get the natural dose of nutrition they usually get in their natural environment. But compost provides similar value to the potting mix by adding different nutrients to the soil.

Along with nitrogen from the coffee grounds, compost also provides other nutrients that your plant might need.

Remember these tips while using coffee grounds as compost:

• Keep a check on the watering. Compost with coffee grounds can retain a lot of water, so make sure you don’t water without checking the soil as that can cause overwatering.
• Compost can produce some smell, but you can mix the compost well with the soil if you want to avoid the smell.
• Excess compost can cause root burn or leaf burn, so only add a moderate amount of 1 inch.

Make a liquid fertilizer with coffee grounds

Instead of pouring coffee on the soil, you can make a liquid fertilizer with the coffee grounds, also called compost tea.

Using coffee grounds as a liquid fertilizer helps to add beneficial bacteria to the soil.

One of the easiest ways of preparing this liquid fertilizer is:

• Take a container and fill it in with water.
• Add coffee grounds to a container.
• Let the coffee grounds soak for 1 or 2 weeks.
• Stir it after few days.

The coffee grounds will break down and release nutrients into the water. You can strain this water and use it on your indoor plants.

Coffee grounds as a mulch

Although mulching is more prevalent in the gardens, you can do this with your indoor plants too. However, you should be careful while adding the coffee grounds.

If you add a balance of other organic matter such as compost or straw along with coffee grounds, your plants can benefit from mulching. Mulching will help retain moisture and keep the plant hydrated.

However, the caffeine in coffee grounds can inhibit the growth of young plants, so you might not want to use this on the younger plants or seedlings.

Is leftover coffee good for plants?

Yes, leftover coffee can benefit your indoor plants, but here is how you should use it:

• Let the coffee cool down. Do not pour hot coffee as that will shock and damage the plant.
• Let the coffee get into the soil without touching the leaves or the flowers of your plant.
• You can add some more water to dilute the coffee.

If you notice that the leaves of your plants are showing brown tips or edges, refrain from using coffee grounds or use less of them.

How do coffee grounds affect the soil pH?

Too many coffee grounds can increase the acidity of the soil. So, before using coffee grounds on the soil, check the pH of the soil with a pH testing kit.

Most indoor plants prefer slightly acidic soil. Coffee grounds can work great on soil with less acidity, as coffee grounds can add acidity to the soil.

However, adding too many coffee grounds can increase the soil’s acidity to a great extent that can be bad for the plant.

Instead of adding coffee grounds directly, brew them and dilute them before adding them to the plants.

You can check the pH of the soil after using coffee grounds for a while to make sure that the pH is still suitable for the plants. If the soil pH has become more acidic, you must stop adding coffee grounds.

Which indoor plants like coffee grounds?

Some indoor plants can benefit more from coffee grounds. These are:

• Jade plant
• Golden pothos
• Philodendron
• Peace lily
• African violets
• Christmas Cactus
• Miniature Roses

However, plants like cacti and succulents do not like coffee grounds.

Things to keep in mind while using coffee grounds on indoor plants:

You should be cautious about using coffee grounds on your indoor plants, as anything wrong can damage the plants.

• Do not use coffee grounds regularly. It would be best to use coffee grounds occasionally. Otherwise, the plants can have root burn.
• Caffeine can be toxic to pets. So keep the plants on which you used coffee away from pets.
• Do not pour hot coffee on the plants.
• Observe your plants after adding coffee to make sure it is not getting harmed.
• Stop using coffee grounds if your plant’s growth gets stunted.

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Source: Coffee grounds benefits, Field Evaluation of Coffee Grounds Application for Crop Growth, Effect of fresh and composted spent coffee grounds.