Having roses is quite an attractive addition to your backyard, but having them with undergrown petals and weak stems isn’t! Fertilizing is key to a stupendous garden and many gardening enthusiasts recommend common byproducts for use as fertilizers instead of spending cash on commercial ones. But what common byproducts work best? Do roses like coffee grounds?
Coffee grounds can be a great natural fertilizer for roses due to their high nutrient and acidity content. Coffee grounds will also attract nearby earthworms that produce their own fertilizer through their waste.
Used coffee grounds may indeed help your roses grow to their full potential, beautifully complementing the overall look of your garden. However, they can harm your roses if used incorrectly. Let’s discover if coffee and roses go well together in your garden as they do on your dates!
What Are Your Roses Looking For?
Roses, like all plants, require the right supply of nitrogen, phosphorus, and potassium (also known as the “NPK” nutrients). The optimum NPK ratio in the soil for maximal growth is nitrogen:phosphorus:potassium 1.0:0.8:0.8.
They also require sulfur, magnesium, iron, manganese, and boron, but these are considered secondary nutrients. I’ll discuss why your roses need each of these nutrients below.
Nitrogen
Nitrogen is needed for the growth of the entire plant and the development of the flowers. Too much nitrogen can cause a lot of foliage and not enough blooming, while too little nitrogen will cause smaller blooms, yellow leaves, and incomplete growth. Nitrogen also assists in the development of microbial populations.
Phosphorus
Author Note: Phosphorus is responsible for the growth of the root system and the emergence of flower buds. Low phosphorus supply can result in closed buds, weak stems, and the premature falling of leaves.
Potassium
Potassium is your rose’s defense line! It helps protect against attacks from insects, disease or rough weather conditions, and water shortages. This happens because potassium aids the lignification of shoots at the end of the growing season so that shrubs wouldn’t die of frost during winter.
Carbon-Nitrogen Ratio
The carbon-nitrogen ratio describes the relative amounts of carbon and nitrogen in the soil below your roses. Soil microorganisms prefer this ratio to be around 24:1 for them to break down organic matter for consumption by the flowers.
Secondary Nutrients
The secondary nutrients are required in very small concentrations. Most soils will readily have a sufficient amount in them. These nutrients include sulfur, which helps with the metabolism of nitrogen.
They also include magnesium and iron. These contribute to the production of chlorophyll, which is responsible for the coloration of the green parts of the plant.
Manganese is responsible for the chemical processes that happen inside the plant. These include respiration, photosynthesis, and nitrogen assimilation which significantly affect the overall health of the rose.
Also, boron deficiency can cause flower drooping after the buds open.
You should be on the lookout for the mentioned effects on your roses. This should help you determine if there is a lack of secondary nutrients. Accordingly, you may want to consider repotting your flowers with better soil.
How Can Coffee Grounds Benefit Your Roses?
The benefits of using coffee grounds aren’t just limited to supplying your roses with essential nutrients. There’s a variety of pros for the soil and the environment as well!
Nutrient Content
As organic matter, coffee grounds contain the NPK nutrients with a ratio of nitrogen:phosphorus:potassium 2.1:0.3:0.3. This isn’t the recommended ratio, but still quite acceptable for a free fertilizer!
The carbon-nitrogen ratio is 20:1, which provides an excess supply of nitrogen to your roses. This means that there’ll be more than enough nitrogen for the demand of soil microorganisms.
However, this can lead to undesirable smells since too much nitrogen causes the production of ammonia. Also, the excess nitrogen concentration can make your flowers foliage-heavy and less bloomy.
Other nutrients found in the chemical composition of spent coffee grounds include potassium, calcium, and magnesium. In addition to sulfur, phosphorus, iron, and more.
Acidity Level
Used coffee grounds have a pH level of about 6.5, which is perfect for growing roses. A pH lower than this will decrease the absorption ability of nitrogen, phosphorus, and potassium.
A higher pH will decrease the plant’s ability to absorb other nutrients like iron and manganese from the soil. These are quite important for the production and utilization of chlorophyll.
Attracting and Feeding Earthworms
Coffee grounds may attract earthworms to the soil around your roses. Their activity is advantageous to the roses since they concentrate the organic content of the grounds.
Earthworms also increase soil stability by cementing soil particles together, which improves root development and increases water-holding capacity.
Additionally, they improve soil drainage and aeration by burrowing small tunnels. These tunnels help the roots of your roses to grow deeper into the soil, resulting in an overall healthier and stronger plant.
Environmental Benefit
Author Note: Using coffee grounds has a positive impact on the environment as they would have otherwise been thrown in landfills. This negatively affects the soil by increasing its acidity.
Used Coffee waste also causes the production of methane which is a greenhouse gas that contributes to global warming.
Besides, using coffee grounds means that you don’t have to buy specifically manufactured fertilizer, which uses a lot of resources to manufacture and distribute.
For these reasons, some environmental institutions initiated campaigns to gather and distribute used coffee grounds. Coffee shops like Starbucks have also joined the trend.
Natural Repellant and Diseases Preventer?
Finally, some people claim that coffee grounds have helped them keep away snails and slugs that ruin their roses, but more research needs to verify this claim.
Used Grounds are also believed to suppress some common fungi, including Fusarium, Pythium, and Sclerotinia species according to some studies.
Fresh Coffee Grounds vs. Used Coffee grounds
If you’re thinking about whether to go for fresh or spent grounds, the answer is simple. Always add used coffee grounds for roses. Firstly, they are free. Secondly, they have a neutral pH which is ideal for roses and earthworms.
Fresh coffee grounds are acidic which can harm your roses. However, they can be used to fertilize other acid-loving plants like blueberries.
When Roses Don’t Like Coffee Grounds
Coffee grounds can give your roses a nitrogen burn if applied directly. This can be fatal for your roses so you have to make sure you correctly apply the grounds.
Also, if not rinsed well, spent grounds can hold some acidity in them which will lower the soil pH. Another issue that can emerge from ineffective washing is caffeine residue, which can inhibit the growth of your roses, so always make sure you thoroughly wash those grounds!
When Should You Apply Coffee Grounds to Your Roses?
A nitrogen supply during autumn or the end of Winter may induce some delicate growth that will be easily damaged by the frost. You need to add your coffee grounds during April and May because that’s when the roses are regaining their liveliness after the winter season. It also means that they won’t be subjected to harsh conditions for the next few months.
After the middle of August, it isn’t recommended to add any more grounds to your rose soil. This is because the plant will need time to harden before the tough winter season, to survive till the next summer.
If you happen to sprinkle grounds after August, the new growth will probably die out during the first hit of winter. You will need to remove the dead parts from your roses with pruners before the entire flower is ruined.
How to Apply the Grounds?
People have countless recipes for using the grounds, but I’ll be discussing the use of plain used coffee grounds. The most important thing to take into consideration while applying coffee grounds is their high nitrogen content. Bear in mind that too much nitrogen in your soil can cause your roots to burn which will ultimately ruin your roses.
Dry Coffee Grounds Method
You’ll need to make sure your grounds are well-rinsed before use, this ensures the right pH level. Evenly sprinkle each rose with about half a pound of grounds, water immediately with a couple of gallons.
There is no need to dig into the ground, sprinkle only on top of the soil to let the grounds break down and reach the roots slowly. The water and earthworms will help gradually introduce the grounds to your roses.
It is recommended to only do this once between the end of winter and the start of spring.
Wet Mixture Method
Another approach is to mix the grounds and water before adding them to the soil. Using the same amounts previously mentioned ( half a pound of coffee grounds and a couple of gallons of water for each rose). Stir and shake well before applying!
This has the benefit of helping you evenly distribute the nutrients, as sprinkling a powder may result in heaps of large concentration in one spot, and areas of low concentration in another. It also saves you the job of having to water after sprinkling.
Conclusion
Roses do like coffee grounds since they contain many of the needed nutrients for optimal growth. You’ll be doing your bank account, the environment, and your roses a favor if you switch from chemical fertilizer to used coffee grounds. So stop throwing away those coffee filters and start saving them for the beginning of the spring.
However, you may still need to add extra fertilizer or repot your roses in cases of deficiency. Also, the high nitrogen content in coffee grounds has its downsides and you may harm your flowers if you don’t rinse the grounds thoroughly.
If you want beautiful looking roses that aren’t burnt and that will continue to serve you through the seasons, make sure you add the correct amount of grounds during the optimum times.
Stay caffeinated friends!