How to Use Coffee Grounds to Help Your Poinsettia Thrive All Season

Poinsettias are a popular holiday houseplant known for their vibrant, colorful bracts that surround tiny yellow flowers in the center. They typically bloom in December and January, adding a cheerful splash of color to any setting. While they are relatively easy to care for, using used coffee grounds as a soil amendment can help poinsettias thrive throughout the season.

Coffee grounds can be beneficial for maintaining your poinsettia's health, but they must be used correctly and at the appropriate times to achieve the best results. Ahead, experts explain the advantages of using coffee grounds to extend your plant’s life and provide straightforward tips on how to do it correctly.

Benefits of Fertilizing Poinsettia With Coffee Grounds

Coffee grounds add a small amount of nitrogen, which supports leaf production and overall vigor of poinsettias, says Christina Koether, a garden designer and flower farmer at Nomadica. "Coffee grounds also contribute organic matter that helps the potting mix hold moisture more evenly, and encourage microbial activity, which helps break down nutrients already in the soil," she says.

Used coffee grounds also contain small amounts of trace minerals such as magnesium and potassium, which can boost your plant's health. Koether recommends using coffee grounds sparingly, as they can increase acidity. "Apply them only when the plant appears stable and well-watered," she says.

When to Fertilize Poinsettia

While coffee grounds can boost the health of your festive plant, it's best to fertilize poinsettias only once every four weeks. "When fertilizing, avoid piling on coffee grounds, especially if the plant is stressed, drooping, or overwatered, since they can hold extra moisture," Koether notes. Additionally, coffee grounds do not provide complete nutrition. "Therefore, also using a balanced houseplant fertilizer every three to four weeks will ensure the plant receives everything it needs."

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How to Fertilize Poinsettia With Coffee Grounds

Fertilizing poinsettias with coffee grounds must be done in moderation, says Ankit Singh, assistant professor and ornamental horticulture educator at the University of Maine Extension. Overuse can lead to soggy soil, mold growth, and nutrient imbalances. To help you fertilize your poinsettia correctly, he offers two effective methods for using coffee grounds as fertilizer.

Method 1: Mix Small Amounts Into the Soil

This beginner-friendly method is easy for gardeners of all skill levels to try. Singh recommends using 1 teaspoon for a 6-inch pot, and up to 2 teaspoons for a 10 to 12-inch pot.

1. Lightly work coffee grounds into the top 1/2-inch of soil.
2. Mix the coffee grounds in well, as it prevents mold, compaction, and surface crusting.
3. Repeat once every four to six weeks during the growing season.
   

Method 2: Make a Diluted Coffee Ground Tea

This method is gentler and easier to control, says Singh.

1. Add 1 tablespoon of used coffee grounds to 1 liter of water.
2. Let the mixture sit overnight.
3. Strain it thoroughly.
4. Use the liquid to water the plant once a month.

When to Stop Fertilizing Poinsettia

Once the bracts fall off and the vivid colors begin to fade, it's essential to stop fertilizing your plant. This signals that the plant is entering its rest period and requires fewer nutrients. Additionally, you should also halt fertilization when the colorful bracts have fully bloomed, indicating they’ve reached maturity. Overfeeding during this stage can lead to stress and even cause the leaves to drop.