Do Azalea Like Coffee Grounds? Positives and Negatives

Azaleas have a requirement for acidic soil. Caffeine grounds are acidic and bear many nutrients, but do azalea like coffee grounds?

The short answer is yes. Azalea can be grown with coffee grounds. But there are certain restrictions like the type of plant and the proposed positive benefits it offers azaleas.

Read on to find out more about the relationship between azaleas and coffee grounds. 

What Are Coffee Grounds?

Small pieces of coffee are most effective because they offer more surface area. These are ‘coffee grounds’. They are small fragments of coffee that are left behind in the filter after brewing coffee. 

These used-up and exhausted grounds are considered the waste material of coffee. They will not be able to impart coffee flavor anymore. 

But, they are not completely useless! You are about to find out how to put your coffee grounds to good use in the garden.

Although the coffee essence is gone, there are still some minerals left within. 

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Benefits of Coffee Grounds To Azaleas

The end of its coffee brewing capacity is not its end of life. Coffee waste in the form of coffee grounds is useful in many ways.

Here are other ways azalea can benefit from your old coffee grounds.

Possible Pest Resistant 

Some garden enthusiasts say that coffee grounds act as a great barrier and deterrent against annoying insect pests.

Particularly slugs and snails who will not be able to get past these somewhat rough granules of coffee. 

But, there is little evidence of this. Researchers argue about this not being true. You can try it out to see if it works for your garden. You may have to be prepared with ‘plan B’ if the coffee grounds don’t work! 

Also, a bit of coffee grounds in the garden can help keep cats away. Yes, many cats dislike the aroma of coffee.

So, there are high chances that they will not eat your plants or use that area as a litter box! It’s worth a shot. 

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Coffee Grounds in Compost

It just so happens that coffee grounds aren’t just rich in Nitrogen. This ‘waste material’ also holds several other minerals. Most of which are required for plants to grow and thrive. 

The elements coffee grounds contains are: 

  1. Potassium
  2. Magnesium 
  3. Calcium 
  4. Other elements in trace amounts 

Actually, all of these minerals exist in a good compost mix that can be added to plants. Especially heavy feeders like azalea plants. The good news is you can still do this, make compost with coffee grounds. 

You just have to make sure you get the ratios right. Putting coffee grounds directly over your plants as a layer is not advisable. You have to mix it in with your compostable household waste. Keep mixing it into the compost.

Household compostable waste is available in two types, green compost material, and brown compost material. 

Green Compost 

  • Coffee grounds (including the filter paper)
  • Tea bags 
  • Grass cuttings
  • Vegetable peels
  • Old flowers
  • Fruit scraps 

Brown Compost

  • Paper/Newspaper
  • Cardboard
  • Egg trays and egg shells
  • Dry leaves
  • Twigs/Branches
  • Straw
  • Nut shells

To keep your compost heap balanced, you must watch how you combine these two types of compost. Usually, keeping it balanced means mixing it in the ratio of 4:1 (brown compost to green compost). 

An excessive amount of green material can create a foul odor from the compost. But, a lack of green material will prevent the compost pile from decomposing because it won’t heat up.

Acidifies Soil 

Spent coffee grounds have a mildly acidic characteristic.

Acidity is something azalea plants need! But, there is a substance more acidic than used up coffee grounds. Unused coffee grounds are more acidic than used ones.

Fresh coffee grounds would be a treat for acidic-soil-loving plants. There are bound to be quite a few of them in your garden. Examples of plants that love soil with acidic pH are:

  • Azaleas 
  • Rhododendrons
  • Hydrangea 
  • Lily of the valley
  • Blueberries 
  • Radish
  • Carrots 

NOTE: Tomato bushes aren’t very fond of coffee grounds!

Also, seedlings and very young plants may be stunted when they come into contact with coffee grounds.

This is because these coffee shards still contain a large amount of caffeine. This substance is not very helpful when it comes to the growth of young plants. 

You don’t even have to make a trip to the store to get unused (fresh) coffee grounds. Everyone has that packet of coffee that is past its date.

Or maybe you have coffee that you don’t exactly like to drink! Instead, using it in the garden would be an appropriate substitute. 

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Adds Nitrogen To Soil

Coffee grounds are popular for having high amounts of Nitrogen. This is great seeing as all plants need this nutrient if they want to grow.

Coffee grounds are a high source of Nitrogen. In fact, around 1.45% of the grounds are this element! 

If you are a regular coffee drinker, you can save your money by not having to buy Nitrogen fertilizer. Your daily coffee grounds and the filter can find better use. 

Azalea plants can benefit from the high amounts of Nitrogen released from the coffee grounds.

Besides this acts as a more natural source of Nitrogen compared to artificial fertilizer. 

Besides, choosing the wrong fertilizer can make the soil alkaline, unsuitable for azalea plants.

At the end of the day, you don’t really know what actually the fertilizer is made from. As well as the effects it will create! 

Worm Attractant

Word is that while coffee may act as a pest deterrent, it can help to attract another useful organism.

If you haven’t guessed already, the mystery organism is ‘worms’. Apparently, worms like coffee grounds. So, adding them to your worm bin is a big benefit that you won’t regret.

Worms are a core soil recycling organism. They help the natural decaying of plant matter which is essential if you plan on planting anything in your garden.

Attracting earthworms is good as they create spaces in the soil. Meaning air gets in the soil and to your plant’s roots.

So while coffee grounds are good for worms, worms are good for your soil as well! These guests will help your soil if you are having trouble degrading compost or getting it to be aery and lighter.

Do Azalea Bushes Attract Bees? Other Insects It Attracts

Weed Killer!

Having to individually take out weeds one at a time is a rather painstaking process that every gardener hates.

But with the help of coffee grounds, maybe there is a way to keep them from ever-growing near your azaleas. 

Composting with coffee grounds may be effective at preventing the growth of weeds. Perhaps it has something to do with the caffeine content of this material.

Either way, just be sure to use it on established plants so they are not also affected by the caffeine. 

Don’t Use Coffee Grounds Alone On Azaleas

Coffee grounds are best when used in compost, combined, and watered-down. But, using it alone and in its true form could prove to be problematic, even for azalea plants.

Adding these coffee grounds to the compost pile is the best and safest option.

Why would anyone dissuade scattering a layer of coffee grounds around plants? It should still provide positive effects, right?

However, there is some truth to this. Actually scattering the grounds as a layer around the plants can create problems.

  1. Coffee grounds could start to stick together. Once this happens the coffee bean shards could form a hydrophobic layer. Unfortunately it gets worse!
  2. Over time, this water repellent layer could favor fungal growth. This could then easily also affect your azaleas or vegetables. 

One solution is to first mix the coffee grounds with dry grass clippings. This mixture will deter sticking together of the grounds.

As a result, conditions will not become suitable for fungal growth. 

We understand that using the grounds immediately without mixing is easier. However, in gardening, whatever is easier is not necessarily better for plants. 

Coffee Grounds in The Garden May Pose Risks! 

What are the possible problems you could face while using coffee grounds? So not all materials have all positives and no negatives! Here are some things to look at with coffee grounds.

Coffee grounds are rich in Nitrogen. But sometimes too much Nitrogen can become more of a burden than a blessing!

That is, if gardeners add too many coffee grounds without checking the mineral profile of their soil, there could be excessive amounts. 

This could result in plants undergoing poisoning instead of growth.

Coffee in all shapes and forms contains caffeine. Sadly, this substance is not kind to small plants and saplings.

Using compost high in coffee grounds will stunt and possibly kill vulnerable plants. Even if they reach these unestablished plants by accident, the diagnosis is grim. 

Relying on coffee grounds to be a pest deterrent may result in extensive plant or vegetable damage. So, take this ‘pest control’ property with a pinch of salt!

Coffee grounds around the garden are not such a great idea if you have pets around. Dogs are notorious for trying to eat almost anything.

Consuming coffee grounds could lead to various side effects such as vomiting, arrhythmia, tachycardia, seizures, etc. In high amounts, it can even lead to death!

Use too much coffee grounds in your compost and soil and your garden could be stuck with it for a while. So, consider it taking 3 to 4 months for this coffee waste to break down completely. 

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Yes, coffee grounds have several positive effects, many of which your azaleas can benefit from. The key is to use the coffee grounds properly.

But, when we say properly, we mean they have to be mixed with brown compost waste in the right ratio. They cannot be used alone!

Some of the benefits of coffee grounds for azaleas are:

  • Could be a pest resistant material
  • Makes the soil acidic
  • High in Nitrogen (as well as other minerals)
  • Worms love coffee grounds
  • Possible weed deterrent

On the other hand, some risks are also present. Avoid using coffee grounds on young plants and seedlings and caffeine can stunt them.

Also, never use coffee grounds directly on azaleas. Coffee grounds as a pest deterrent are also still not scientifically proven. 

But, it is still worth trying to add coffee grounds to your compost heap for your azalea plants!


Which plant likes coffee grounds?

The plants that are like coffee grounds are Azaleas, Rhododendrons, Hydrangea, Blueberries, Carrots, radish, and Lily of the valley.

How to use coffee grounds as fertilizer?

You must mix your coffee grounds with brown compost material. Mix them in the ratio 4:1 (brown compost material is to green compost material). Be sure to keep to this specific ratio to avoid bad compost.