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Perking Up Your Crepe Myrtles: The Benefits of Coffee Grounds

Coffee Grounds for Crepe Myrtles: A Comprehensive Guide

If you’re a gardening enthusiast, you may have heard of using coffee grounds as fertilizer for certain plants. But are they suitable for crepe myrtles?

In this article, we’ll explore the benefits of coffee grounds for crepe myrtles, how they affect the soil’s pH levels, and how to use them effectively. Soil Specifics: What Crepe Myrtles Need

Crepe myrtles thrive in well-draining soil with a pH between 5.5-7.0. They’re prone to root rot if the soil is too wet or compacted, so it’s crucial to ensure adequate drainage.

Adding organic matter to the soil improves its structure and increases its capacity to hold moisture. Nutrients that crepe myrtles need include phosphorus, nitrogen, and potassium.

A soil analysis can reveal if there are any nutrient deficiencies. All-purpose garden fertilizers usually contain these necessary nutrients, but there are alternatives like coffee grounds worth exploring.

Using Coffee Grounds as Fertilizer: The Pros and Cons

Coffee grounds are an excellent source of nitrogen for plants. They have a small amount of phosphorus and potassium but insufficient quantities to meet crepe myrtles’ requirements.

Fine coffee grounds are preferable to coarse ones as they break down quicker in the soil, releasing nutrients more efficiently. However, coffee grounds can be too acidic, which can harm crepe myrtles.

They have a pH between 4.0-5.0, which falls in the acidic range of the pH scale. A carbon to nitrogen ratio of 20:1 in coffee grounds promotes beneficial microbial activity in the soil but can be detrimental in high concentrations.

It’s essential to use coffee grounds in moderation, either by incorporating them in compost or spreading a thin coating on the soil surface around crepe myrtles. Coffee grounds add organic matter to the soil, lowering its bulk density, and enhancing its water-holding capacity.

When to Stop Fertilizing Crepe Myrtles

As fall approaches, crepe myrtles transition into dormancy, and their nutrient requirements decrease. Hardening off occurs when the plant stops growing actively and prepares for winter.

Fertilization during this time may disrupt this process and cause frost susceptibility, so it’s best to stop fertilizing crepe myrtles in late summer.

How to Use Coffee Grounds as Fertilizer

To use coffee grounds as fertilizer, start by adding them to your compost bin. Combine them with other organic matter like leaves, grass clippings, and food scraps to provide a balanced blend of nutrients.

As they decompose, the nitrogen compounds in the coffee grounds break down, increasing their availability to plants. Another method is to spread a thin layer of coffee grounds around the base of crepe myrtles, avoiding direct contact with the plant’s stem.

This will prevent the coffee grounds from interfering with moisture and nutrient uptake.

Benefits of Coffee Grounds for Plants

Coffee grounds contain organic material, which improves soil structure, enhances drainage, and increases water retention. They are also an excellent source of nitrogen, promoting healthy leaf growth and reducing weed growth.

Coffee grounds encourage microbial activity in the soil, which supports beneficial earthworms and other soil organisms. Coffee Grounds and pH Levels: What You Need to Know

Coffee grounds are acidic, which affects the soil’s pH levels.

While some plants like acidic soil, crepe myrtles do best in neutral to slightly acidic soil. Adding too many coffee grounds can lower the soil’s pH, leading to nutrient deficiencies and plant damage.

Plants that Like Coffee Grounds

Plants that prefer acidic soil, like hydrangeas, rhododendrons, lily of the valley, hollies, roses, azaleas, fruits, and vegetables, can benefit from coffee grounds. These plants thrive in soil with a pH between 5.0-6.5, making coffee grounds an ideal supplement.

Plants that Don’t Like Coffee Grounds

Plants like lavender, orchids, rosemary, yucca, pothos, tomatoes, and seedlings prefer neutral to slightly acidic soil. Using too many coffee grounds can lower the soil’s pH below optimal levels, leading to stunted growth and other issues.

Using Leftover Coffee to Water Plants

Brewed coffee contains a small amount of nitrogen, which makes it an excellent fertilizer in moderation. Adding sugar can increase its effectiveness, but it’s crucial to dilute it with water to prevent over-application.



Coffee grounds are a beneficial supplement to soil for plants like crepe myrtles when used in moderation. They provide a source of nitrogen, encourage microbial activity, and add organic material to the soil.

It’s essential to monitor the soil’s pH levels and ensure adequate drainage to avoid root rot. Consider composting coffee grounds or using them as a thin layer around the base of your plants to enjoy their benefits.

Tips for Fertilizing Crepe Myrtles with Coffee Grounds

Crepe myrtles can add vibrant colors to your garden with their beautiful flowers and foliage. However, they require proper care and maintenance to thrive.

Nutrient deficiencies can lead to stunted growth and unsightly foliage, but fertilization with coffee grounds can help address these concerns. Here are some tips for using coffee grounds as a fertilizer for crepe myrtles.

Frequency of Fertilization

Fertilization frequency depends on various factors, including the plant’s age and its location. Younger crepe myrtles require more frequent fertilization, compared to established ones.

Applying coffee grounds early in spring helps supply the plant with vital nutrients it needs to grow and flourish during the growing season. Younger crepe myrtles may require monthly fertilization during the growing season, while established ones can get by with two to three doses a year.

The key is not to over fertilize, as it can harm the plant and lead to excessive growth, which is prone to disease and insect infestations.

How to Apply Coffee Grounds

It’s essential to apply coffee grounds correctly to prevent soil acidity from reaching harmful levels that can damage the plant. Start by applying a thin coating of coffee grounds on the soil surface around the base of the crepe myrtles.

For best results, mix coffee grounds into soil before planting, or cultivate the soil around established crepe myrtles to improve nutrient uptake. Covering the coffee grounds with organic matter, like leaves or mulch, helps to regulate the soil’s pH level, preventing acidity build-up.

Excessive coffee grounds application can lead to nitrogen toxicity, a condition in which too much nitrogen concentration in the soil burns the plant’s roots, leading to reduced growth.

Using Coffee Grounds in Compost

Adding coffee grounds to compost can help create a nutrient-rich organic mixture that improves soil fertility. However, it’s important to use coffee grounds in moderation to avoid overloading the compost pile with nitrogen.

A good rule of thumb is to use coffee grounds at a 20% limit to balance carbon and nitrogen. Paper coffee filters can also make an excellent addition to compost, providing an optimal source of carbon material that balances nitrogen-rich coffee grounds in the compost.


Benefits of Coffee Grounds for Plants

Apart from fertilization, coffee grounds offer other benefits to plants that enhance their health and vitality. Here are some miscellaneous benefits of coffee grounds for plants.

Repelling Insects

Coffee grounds have a unique aroma that repels insects, including snails, slugs, ants, and even cats. Strategically placing coffee grounds around the base of crepe myrtles can keep these pests at bay, preventing damage to the plant.

Attracting Earthworms

Coffee grounds contain organic matter that attracts earthworms, which help maintain soil aeration and health. Earthworms create tunnels that increase water infiltration and nutrient uptake, contributing to the plant’s overall growth and development.

Adding coffee grounds to compost can also attract earthworms to your garden, making it a win-win situation.

Cautions When Using Coffee Grounds

It’s important to be mindful of potential hazards when using coffee grounds in the garden. Applying too much coffee grounds can lead to yellowing leaves, a sign of nutrient deficiency.

Coffee grounds can also harbor strong odors that can dissipate with time. Additionally, using strong coffee can negatively affect young seedlings or other sensitive plants.

Pruning Crepe Myrtles

Pruning crepe myrtles plays a vital role in maintaining plant health. Winter is the best time to trim back crepe myrtles while they are dormant.

Cutting back the branches encourages new growth, increases flowering, and helps maintain plant structure.


Coffee grounds make a valuable addition to your gardening routine, providing an affordable and eco-friendly way to nourish your crepe myrtles. By applying coffee grounds correctly, you can give your plants the necessary nutrients they need to thrive.

Additionally, coffee grounds offer other benefits such as repelling insects and attracting earthworms, making them a fantastic supplement to your garden’s overall health.

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