Peonies (Paeonia species) are long-lived plants known for their beautiful blooms and strong roots, often lasting for decades with proper care. I am excited that one day I my girls will be able to take some of my peonies to their homes and they will last their lifetime too. Peonies are such a special flower in that way. As flower enthusiasts, we are always searching for the best ways to encourage vibrant growth and stunning flowers. One common question is whether coffee grounds can be beneficial to peony plants as fertilizer.

Let's explore whether coffee grounds are a good idea for peony bushes and discuss the best practices for fertilizing peonies to ensure healthy growth.

Fall is the best time to plant peony roots. I have created a free download with planting tips, my favorite peony varietals, my favorite places to purchase peonies, companion plants, my favorite Spring bulbs, and more.

If you already have peonies in the ground, it's time for fall cleanup. You should cut your peonies back and dispose of the plant material. It is very important that you do not chop and drop peony foliage nor should you compost it. Peony foliage is very prone to disease like botrytis and powdery mildew. These pathogens will persist in the soil and in your compost pile. This is one of the very few things that I will tell you to throw away.

The Power of Coffee Grounds: Myth or Reality?

Coffee grounds are often touted as a beneficial soil amendment because they add organic matter to garden beds. However, not all plants thrive under the same soil conditions. For instance, peonies prefer neutral to slightly alkaline soil, while coffee grounds can contribute to acidic soil. The pH level of your soil is a key factor to consider when deciding whether to add coffee grounds.

Peony plants typically thrive in well-draining soil with a pH between 6.5 and 7.0. Adding coffee grounds, which can lower soil pH, might not be ideal, especially if your garden soil already tends to be acidic. Before using coffee grounds on your peonies, it’s important to perform a soil test to determine the current soil pH. If you live in the Richmond, VA area, I think that you will find that our soil is naturally acidic. The ideal time to test your soil is in late winter or early spring, but now is okay as well and may be faster because labs aren't backlogged with those eager Spring gardeners. By performing a soil test now, you are giving you time to adjust the soil conditions before the growing season begins. I can perform soil tests as a part of my garden consultations or you can utilize your local extension office.

Benefits of Coffee Grounds for Soil Structure:

While coffee grounds might not be the best fertilizer for peony plants, they can still benefit the soil structure. Coffee grounds, when composted properly, improve the texture of the top layer of soil. This enhances soil drainage and aeration, which is critical for peonies that prefer well-draining loamy soil. Mixing coffee grounds into a compost pile can be an easy way to boost the organic matter in the soil without directly affecting the pH balance around the base of the plant.

However, applying fresh coffee grounds directly to the soil surface might not be the best practice. Fresh grounds can compact, reducing soil drainage, which could harm peony blooms and new shoots. If you’re set on using coffee grounds, the best way is to compost them first and then add them as part of your soil amendment process in late fall or early spring. You can put them in any composting method of your choice. I use Bokashi as my way to harness important nutrients from my food waste. It is the best choice for my family and our lifestyle, but you may find another composting methods works great for your needs too.

What Type of Fertilizer should I use on my Peonies?

The right fertilizer can help your peonies thrive throughout the growing season, especially during the early summer and late spring when flower buds are forming. While coffee grounds may not offer the full range of nutrients peonies need, there are other fertilizer options that are better suited to peony growth.

Peonies benefit most from a slow-release granular fertilizer applied in early spring, as new shoots emerge from the soil. Bone meal, which is high in phosphorus, is a great choice for encouraging strong root development and vibrant flowering plants. A balanced slow-release fertilizer or a fertilizer high in potassium will also support plant growth and beautiful blooms. Granular, slow-release fertilizers are great for the busy gardener. I like Espoma organic products. You simply apply these products at the root zone of the plant. You'd use Flower-Tone monthly in the early Spring to promote large blooms. After your peonies bloom, you can switch to a fertilizer that promotes root development. On the farm, I foliar feed my peonies with Neptune's Harvest Emulsion bi-weekly during the growing season. I also use copper fungicide immediately upon shoots emerging to prevent botrytis.

When is the Best Time to Apply Peony Fertilizer?

The best time to fertilize peonies is in early spring when new shoots appear. A second application of liquid fertilizer can be made in early summer after the peony flowers have bloomed, helping to build strong roots and prepare the plant for the next flowering season.

For new plants, incorporating a slow-release granular fertilizer into the soil during the planting time is key to establishing a healthy foundation. Organic matter, such as compost or well-rotted manure, can also be added to improve soil quality and structure.

Remember: The label is the law. Follow the application rates listed on any fertilizer or chemical that you apply to your garden.

Other Factors for Growing Healthy Peonies

In addition to using the right fertilizer, it's important to consider other aspects of peony care to ensure optimal growth and blooming. Planting peonies in full sun is essential, as they require at least six hours of sunlight daily to produce their best flowers. Be sure to avoid planting peonies in spots with poor drainage, as waterlogged soil can lead to root rot and reduced plant growth.

Regular monitoring for diseases like powdery mildew is crucial. While coffee grounds won’t help prevent fungal issues, maintaining proper spacing between peony bushes and ensuring good air circulation around the plants will reduce the likelihood of disease. In a landscape setting, peonies should be spaced at 3 foot on center unless you plan to dig and divide every few years. In cut flower production, we space our plants at 24 inches apart because we will be cutting some of the foliage out with the flowers which allows for the proper airflow needed.

The Bottom Line: Are Coffee Grounds the Right Fertilizer for Peonies?

While coffee grounds may not be the best fertilizer for peony plants due to their tendency to create acidic soil, they can still be a valuable addition to your compost pile, improving soil structure and drainage. For the best results with peonies, bone meal, slow-release granular fertilizer, and compost are recommended. Always ensure you’re fertilizing at the right time—in early spring and early summer—to give your peonies the nutrients they need for beautiful flowers and healthy plant growth. Not a coffee drinker? Ask your local coffee shop or Starbucks for free coffee grounds.

Need help designing the perfect garden bed? I offer garden consulting services that can take the guesswork out of plant selection, placement, and care. Whether you're interested in creating a native plant garden, improving your soil quality, or simply want to know the best plants for your conditions, my personalized consultations are designed to help you achieve your dream garden with ease.

As your garden coach, I can assist you with:

Assessing soil conditions and providing recommendations for soil amendments
Creating sustainable and pollinator-friendly garden designs
Offering advice on the best plants for your specific climate and garden goals
Helping you avoid common mistakes, like over-planting or choosing the wrong plants for your garden’s sun and shade balance

Ready to get started? Learn more about my services here and book your consultation today!

Until Next Time Flower Friends, Keep Blooming,

Nicole Dillon

Owner of Breemar Flower Farm and Founder of Your Garden Pathway Ashland, VA | Zone 7b

References:

Penn State Extension. (n.d.). Fertilizing Flower Gardens and Avoid Too Much Phosphorus. Available at: https://extension.psu.edu/fertilizing-flower-gardens-and-avoiding-too-much-phosphorus
Clemson Cooperative Extension. (2020). Peonies. Available at: https://hgic.clemson.edu/factsheet/peonies/
University of Vermont Extension. (2015). Peony Care. Available at: https://pss.uvm.edu/ppp/articles/peonycare.html

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Do Peonies like Coffee Grounds for Fertilizer?