Coffee grounds and other sorts of organic materials (e.g., leaf mulch, aged manure, yard, and garden compost) incorporated into the soil will improve soil structure and drainage.
Organic matter breaks down steadily, providing slow feeding and supporting beneficial fauna in the soil, such as earthworms.
These qualities work together to make the soil more nourishing and make it easier for plants to uptake that nourishment.
For these reasons, roses (and many other plants) are definitely like coffee grounds.
What You Need To Know About Using Coffee Grounds In Rose Gardening Q&A
1. Are Coffee Grounds Harmless To Rose Bushes?
Like many things, excessive use of coffee grounds can be detrimental to rose bushes and plants.
For example, adding many coffee grounds to the soil around your rose bushes could burn their roots.
It’s best to spread coffee grounds lightly over the soil’s surface (staying away from plant stems) or mix them into your compost mixture rather than incorporating them into the soil.
2. Are Coffee Grounds Acidic?
For the most part, coffee grounds are near neutral pH.
However, fresh coffee grounds may be a bit acidic, and some types of coffee are more acidic than others.
As the grounds break down, the acidity lessens, so composted coffee grounds and those spread lightly over the soil’s surface.
Be careful not to place them right next to the base of your rose bushes should provide just the right amount of acidity to keep roses happy.
3. How Do You Compost Coffee Grounds?
The most effective way to include coffee grounds in your garden compost mix is to layer between dry leaves and fresh grass clippings.
Try to create layers of an equal amount of each ingredient.
Alternatively, you can compost coffee grounds by mixing them with shredded paper and coffee filters.
This can be done in an indoor bin if you don’t have a garden compost heap.
More on Coffee Grounds in Compost
4. How Do I Fertilize Rose Bushes With Coffee Grounds?
You can either spread about half a pound of grounds around each of your rose bushes and then water them in with a couple of gallons of water per half a pound of grounds.
You can also create a slurry of half a pound of grounds and two gallons of water, which you would apply using a watering can.
You can mulch over the coffee grounds with compost, bark mulch, or leaves if you want.
However, many gardeners report that a layer of coffee grounds on the soil surface repels slugs and snails.
5. How Do Coffee Grounds Add Nourishment To Soil?
Coffee grounds are rich in the following:
All of these are essential for vigorous plant growth and provide a great deal of support for rose bushes during the growing season.
In addition, nitrogen is beneficial in stimulating the growth of foliage, stems, and cane.
6. When Is The Best Time To Feed Roses With Coffee Grounds?
Spreading coffee grounds over the soil in the springtime will help promote vigorous growth and disease resistance. Wait until all danger of frost has passed, though.
Applying coffee grounds too early can stimulate growth too quickly. Tender new growth is very susceptible to late frost damage.
7. Should You Use Coffee Grounds In Pre-Winter Mulch?
You can mulch with finished or nearly-finished compost containing coffee grounds, but don’t use fresh grounds.
The nitrogen in fresh coffee grounds might cause your rose bushes to put out new growth too late in the season.
If this happens, the new foliage and buds might be killed off by early frost. This creates the potential for fungal growth.
8. How Do Coffee Grounds Improve The Structure Of The Soil?
Organic matter possesses an essential combination of absorbency and texture.
For example, the coarse nature of coffee grounds creates a light and airy soil mix that allows excessive amounts of water to drain off.
Simultaneously, the grounds are absorbent and retain just the right amount of water to provide moisture to growing roots a bit at a time.
9. How Do Coffee Grounds Support Beneficial Fauna In The Soil?
Friendly, helpful earthworms especially enjoy coffee grounds.
The worms eat the grounds and transform them into mineral and nutrient-dense worm castings to provide your roses with a steady supply of all-natural fertilizers.
In the process, earthworms tunnel through the soil, aerating it and improving its drainage capabilities.
Earthworms aren’t the only beneficial fauna that like coffee grounds, though. Many beneficial microorganisms need nitrogen in coffee grounds to thrive. [source]