How to Use Eggshells and Coffee to Improve Your Plants

Don’t throw away your used coffee grounds and eggsheels! They can act as the perfect DIY fertilizers. Read on to learn how to use them effectively in your garden.

Eggshells Add Calcium to the Soil

One of the main reasons that eggshells can be an effective fertilizer is that they are full of calcium. In fact, a dry eggshell is about 95% calcium carbonate. Calcium carbonate, also known as lime in the gardening world, can help strengthen your plants’ root systems and can help your plants avoid blossom end rot, a condition that can ruin the fruits of plants like tomatoes and peppers. Blossom end rot arises when your plants don’t have access to enough calcium.

Eggshells Make Soil Less Acidic

Another fantastic benefit of eggshell fertilizer is that it can help make your soil less acidic. While many plants will thrive in acidic soils, others require soil that is more neutral or alkaline. When soil is too acidic, it can become difficult for some plants to absorb vital nutrients from the soil. The calcium carbonate in eggshells helps raise the soil’s pH, making it more alkaline and allowing your plants to absorb the nutrients they need.

Eggshells Can Discourage Pests

Eggshells can also be a useful way to get rid of certain pests in your garden. The sharp edges of crushed eggshells can harm soft-bodied pests, such as slugs and other insects, which can deter them or even kill them outright. All you need to do is scatter some roughly crushed eggshells around your plants, and soon these pests won’t be an issue. The downside to this method is that while larger eggshell pieces are best for deterring pests, they take much longer to break down, meaning that your eggshells will be less effective as a soil amendment.

How to Prepare Eggshells to Use as Fertilizer

If you want to use your leftover eggshells as fertilizer, you’ll be pleased to learn that it is very easy to do. Start by washing your eggshells and allowing them to dry. Once the eggshells are dry, you can crush them using a mortar and pestle, a coffee grinder, a rolling pin, or any other tool you think will work. Remember that crushing your eggshells into a fine powder makes it much easier for them to absorb into the soil so that your plants can use them immediately. Leaving your eggshell pieces a bit larger is better for those interested in pest control rather than soil enrichment.

How to Apply Eggshell Fertilizer to Your Soil

Adding your crushed eggshell fertilizer to the soil is also very easy to do. Typically, it is best to lightly till your eggshells into the soil in the late fall. Applying in late fall gives your eggshells a better chance to absorb into the soil and become readily available to your plants once new growth resumes in spring.

Here’s how to get started with coffee grounds in the garden.

Why Use Coffee Grounds in the Garden?

You might value coffee beans mostly for their flavor and caffeine content, but spent coffee grounds have many other advantages as well. They contain approximately 2% nitrogen by volume, meaning that they add vital nutrients to depleted soil.

Just note that you’ll want to add a more concentrated nitrogen fertilizer at the same time you apply them. Coffee grounds promote the growth of beneficial soil microorganisms, which will munch through all nitrogen present. Adding more ensures that there is enough nitrogen for your plants as well.

Beyond their nutritional content, coffee grounds also improve soil tilth, structure, and water retention. They are an excellent addition to any compacted soil that you need to make easier to work, which creates better habitat space for earthworms.

Finally, many gardeners find that sprinkling coffee grounds around their plants keeps slugs and snails away.

How to Apply Coffee Grounds in the Garden

There are many strategies for applying coffee grounds to plant beds. Some gardeners will sprinkle them directly on the soil before planting so they get blended into the bed.

Others apply the grounds after the growing season and then cover them with leaves, fresh compost, or bark mulch. The grounds will break down by planting time. Finally, it’s also possible to incorporate coffee grounds into your compost pile to apply in the spring.

Coffee grounds offer a low-cost, versatile soil amendment to make your garden stand out. So long as you limit their use to plants that they can most benefit — and not harm — spent coffee grounds are a proven way to keep things at their peak.

Best Plants to Fertilize with Coffee Grounds

Not all plants benefit from used coffee grounds. Since the grounds are slightly acidic, they best serve acid-loving plants like hydrangeas, azaleas, rhododendrons, carrots, radishes, and other root vegetables. Fruit lovers will find they are the perfect way to perk up blueberry bushes.

Note that coffee grounds will inhibit the growth of some plants, so keep them away from your geraniums, tomatoes, Chinese mustard, and asparagus.