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Are Eggshells Good for Rhododendrons? How To Apply Correctly

Are Eggshells Good for Rhododendrons? How To Apply Correctly

Maintaining the original beauty of a garden can be achieved by incorporating vibrant rhododendron plants. Speaking as an avid gardener, I must say that a thriving rhododendron shrub is a delightful sight.

I have several years of experience in growing these plants, and I know the tricks of the trade. 

Are eggshells good for rhododendrons? Eggshells are good for rhododendrons. Eggshells provide additional calcium and act as a fertilizer as they break down. Another benefit is that eggshells will help ward off pests such as snails and slugs. Wash and grind or crush the eggshells before use to speed decomposition.  

In the following you’ll learn how eggshells can help your rhododendrons and how you should apply them to your garden.

Feeding your rhododendrons with eggshells isn’t as simple as it sounds. If you do it the wrong way, it will end up being a waste of time, so let’s get started. 

Using Eggshells for Your Rhododendrons

Crushed eggshells are a great natural food to give your rhododendrons for a calcium-boost and fertilization. 

Benefits Eggshells Provide for Rhododendrons

Eggshells offer many benefits for your rhododendron plants. Adding eggshells to the soil near your rhododendrons will: 

1. Provide More Calcium – Like with other plants, calcium is necessary for rhododendron growth and general health. 

2. Fertilize the Plants – While rhododendrons often require no fertilization if they have the right kind of soil, adding eggshells will provide a nutrition boost. 

3. Repel Pests – Adding crushed eggshells to the soil surrounding your rhododendrons will help keep pests such as slugs and snails away. However, you must carefully wash the eggshells first. 

How To Use Eggshells for Rhododendrons

Before you use eggshells to feed your rhododendrons, you must prepare them correctly. There are two methods for doing this. 

Method #1 

1. Rinse eggshells in cold water – Thoroughly rinse your eggshells with cold water. Tap water is fine to use for this.

2. Sterilize eggshells in the microwave – Put the eggshells on a paper towel, and put them in the microwave for three minutes

3. Crush the eggshells – Put the eggshells in a container, and use a wooden spoon to crush them, getting the shells in the most minuscule pieces possible. The smaller the pieces, the faster the calcium can be used by your rhododendrons. 

Now that you’ve finished preparation, proceed with incorporating the eggshells into the soil around your rhododendrons. 

The second method is to make a liquid solution with your eggshells. Many homeowners find this more effective, as the calcium is more readily available to the soil. 

Method #2

1. Boil the eggshells – Boil between 10 and 20 eggshells. 

2. Leave eggshells in the water overnight – Once you’ve taken the eggshells off the boil, leave them in the liquid overnight. 

3. Remove the eggshells – Use a strainer to take the eggshells out of the water, and dispose of them or add them to your compost heap

4. Put the liquid into a container – Transfer the water into a container, such as a jug, that you can bring into the garden. 

5. Pour this solution on the soil – Aim to give each rhododendron plant about 2 cups of the liquid. You can do this as often as twice a month. 

How Long Eggshells Take To Breakdown in Soil

A woman's gloved hand spreading crushed eggshells over garden soil.

Avoid putting large pieces of eggshell on your garden. These will take a minimum of one year to break down and for their calcium to be available to your rhododendrons.

If you want fast results from the eggshells, grind up the eggshells as much as you possibly can. 

The fastest way to get eggshell calcium into the soil is to create the eggshell solution we discussed earlier.

Remember, you extract the calcium from the eggshells by boiling them, and the resulting water is the solution you give to your rhododendrons. 

How To Speed Eggshell Decomposition

The best way to speed eggshell decomposition is to grind up the shells as much as possible before putting them in the soil. 

1. Wash the eggshells with cold water.

2. Dry out the eggshells on a flat surface, such as a cookie rack.

3. Put the eggshells in a blender/food processor.

4. Use this eggshell powder in your garden.

Best Fertilizer for Rhododendrons 

If the soil is already rich in nutrients, you probably won’t need to use fertilizer for your rhododendron plants.

If you have poor soil, however, you can use commercial or natural fertilizers in your garden. 

Best Commercial Fertilizer for Rhododendrons

If you need to use a fertilizer, get one made for rhododendrons. My favorite is Dr. Earth Acid Lovers Organic Fertilizer.

This is an organic fertilizer that offers the best balance and supply of nutrients for rhododendron plants.

It makes sure the soil stays at the optimal acid level, which is important for plants that need acidity, such as rhododendrons. 

Best Natural Fertilizer for Rhododendrons

There are several different natural materials you can use as a natural fertilizer for rhododendrons. One is compost containing washed seaweed, alfalfa, evergreen needles, and oak leaves.

You can also add fish meal, canola meal, or blood meal in between the layers. Create this compost to fertilize your rhododendrons. 

Related Questions: 

Do Rhododendrons Like Coffee Grounds and Eggshells? 

Yes, rhododendrons may respond positively to coffee grounds. If you wish, you can apply coffee grounds at the same time as you do finely ground eggshells. 

To use coffee for your rhododendrons, take the coffee grinds out of your coffee maker filter and put them around your rhododendrons.

This will give your plants a great source of extra nitrogen, magnesium, phosphorus, and potassium, as well as copper. Additionally, coffee grounds will help boost the acidity level of the soil. 

Are Eggshells Good for Roses? 

Yes, eggshells are good for roses. It’s best to grind up eggshells to a fine powder before you use them.

Feeding your roses with eggshell powder gives them extra calcium that they can use to strengthen their cell tissue.

Eggshells can be so useful for roses that many gardeners put some eggshell powder in planting holes and incorporate them into the soil before planting a new rose.  


Eggshells may benefit your rhododendrons, but only if you use them the right way. Crush and grind your eggshells into the finest possible powder so the calcium is released more quickly.