Last Updated on December 29, 2022 by Cristina
Do roses like coffee grounds? Yes, but you do need to apply this natural fertilizer correctly! Coffee grounds are an excellent source of nitrogen and a few trace elements. Find out how to use your coffee grounds for your roses!
Coffee grounds are an excellent soil amendment. They are rich in nitrogen and organic matter. To understand how to formulate a fertilizer for your roses that uses coffee grounds as a component, or just add coffee grounds to the roses, we need to look at a few facts.
What Is The Composition Of Coffee Grounds?
Coffee grounds consist of organic compounds that have been roasted to various levels. The result of this roasting and the natural components in the grounds means that the coffee grounds contribute nitrogen-containing compounds, phenols and polyphenols, tannins, and many other compounds to the soil.
When I see phenols and polyphenols I immediately think a bit further, because these compounds can actually lock out nutrients by adsorbing them (nutrients stick to the coffee grounds and become unavailable to plants). I also immediately think about fungi – because certain fungi will break down these phenols and other complex organic molecules.
I am sure there are lots of articles on how to add coffee grounds to your roses available on the internet, but this article will present a unique perspective, based on experience in the biodegradation of phenols to this method. I personally have used coffee grounds in large quantities – 3-4 x 5-gallon buckets per week – in my garden, and have learned how to do this so that I do not damage my plants.
What Type Of Rose Grower Are You? – Do Roses Like Coffee Grounds?
There are two broad types of rose growers: People who grow in soils that are fed with chemical fertilizers, and the soil is really just something to hold the plant roots. Natural living soil growers create soil that nourishes the rose and will keep feeding the soil so that it can feed the roses.
If you are in the second category, coffee grounds can help you, and if you are in the first category I would probably suggest not using coffee grounds as the grounds will inhibit the absorption of the chemical fertilizers that you add to your non-living soil.
Coffee Grounds For Roses Using Living Soils
Do roses like coffee grounds? In living soil, they thrive on coffee grounds. We provide food for the living soil, and this food enables microbes (Bacteria and fungi) as well as earthworms and other soil organisms to process these foods and release nutrients for the plants that grow in the soil. Coffee grounds can be incorporated below the mulch layer of your roses if you have living soil.
The coffee grounds are an excellent food for earthworms, and certain fungi, that will both break these down and release nutrients for your plants. This is the ancient cycle of life as nature intended it, and these soils that are living are always the best for plants.
If you use coffee grounds to supplement a living soil place three cups of coffee grounds in the layer below your mulch. I add some wood ash – 1 cup – and bone meal – 1 cup. This approximates a rose fertilizer in terms of its NPK value. You put the nutrients in this area because this is the area where there is oxygen because the fungi that break down polyphenols use oxygen to do this. Earthworms will also eat the coffee grounds and become quite active after this! The caffeine in the coffee grounds seems to give them a buzz.
Are Coffee Grounds Good For Roses On Their Own?
My general observation is that if you do not have living soil, coffee grounds on their own can actually make your leaves go yellow due to excess nitrogen or nutrient lockout of other nutrients. This is corroborated by some friends I have who engage in high-end cultivation of certain plants in the US where such plants are legal. Coffee grounds are good when mixed in living soil.
How Often Should You Put Coffee Grounds On Roses?
I would suggest every 6 weeks, using the above ratio of wood ash and bone meal placed below the mulch. This works very well for roses, and for tomatoes, and certain other plants that have attained more legal status recently in much of the world.
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Are Coffee Grounds Good For Knockout Roses?
Coffee grounds in living soil are good for any roses if applied using the above mixture and using a mulch layer to facilitate their breakdown. Knockout roses are relatively heavy feeders due to their abundant flowering nature. I have personally not grown this cultivar, but have grown older Banks roses that appear to have a similar growth pattern, so I would imagine that this would work just as well on knockout roses given the similarity in growth and flowering patterns.
Secret Hack: A Side Note On Mushrooms In Your Soil
I grow about ten types of edible and educational mushrooms – many of these I actually grow on spent coffee grounds. I have found that if I take the leftover media after mushrooms have fruited and mix that into the soil, I often get little clumps of mushrooms sprouting under my plants later. I also mix shiitake and as I say, the education enhancers in there too. You never know what you will find in the garden this way, but whatever it is, it is great.
In Conclusion – Do Roses Like Coffee Grounds?
Do roses like coffee grounds? Yes and no. If you incorporate these in such a way that the nutrients can be released for the benefit of the plants, they are perfect! Living soils amended with coffee grounds, bone meal, and wood ash, and covered in mulch convert coffee grounds into an excellent source of nutrients for the roses.
Dr. Garth A. Cambray is a Canadian/South African entrepreneur and beekeeper with 28 years of experience in apiculture and specializes in adding value to honey. His Ph.D. research developed a new advanced continuous fermentation method for making mead that has resulted in a number of companies globally being able to access markets for mead. His company, Makana Meadery, exports honey mead to the USA where it is available to discerning connoisseurs. He has also developed technologies to commercially manufacture organic honey vinegar in Zambia for export globally. He holds a few patents globally in the ethanol industry and believes in technology and knowledge transfer for human development and environmental sustainability. One of his proudest achievements is the fact that the wind farm he started at one of his old apiary sites has essentially made his hometown carbon neutral.