Find out if using coffee grounds on rose bushes is a good thing.
You may have heard that old coffee grounds are great for sprinkling around your rose bushes because they help roses to grow.
This is true, but you’ll need to know a bit about when and how to do it, to avoid damaging your plants.
If you add too many coffee grounds, you may end up ‘burning’ the roots of your roses or creating a crusty layer of dried-out coffee around your plants. Not good.
And if you add coffee grounds at the wrong time of year, it could cause parts of your rose bushes to die as winter approaches.
So, for peace of mind, check out our comprehensive guide below and find out the best ways to use coffee grounds for roses.
Coffee grounds for roses – how does it work?
Coffee grounds contain nutrients that roses need. Nitrogen is the most important of these. A boost of nitrogen in the spring as roses are starting to grow again will be very welcome.
Besides nitrogen, coffee grounds contain minerals that help roses to grow, including phosphorus, copper and potassium. These minerals will improve the overall health of your soil, which makes for happy roses.
The trick is to make sure you are adding your coffee grounds to your rosebeds at the right time and in the correct quantity.
Below you’ll see there are a few different ways to add coffee grounds to your roses. Adding too much coffee can harm your rose bushes, so it’s worth getting it right.
Best ways to use coffee grounds for roses
1. Add coffee grounds to your compost
By mixing up coffee grounds into your compost, you will be adding nutrients and dispersing them effectively. Class your coffee grounds as green waste – in other words, just like your food waste. You can use your coffee-fuelled compost anywhere in the garden as a fertilizer.
For roses, add a layer of compost around each plant to stop weeds from coming through, improve the soil, and retain moisture. Avoid putting compost right next to the stem of the rose as this could cause rot. Leave at least an inch gap all around the plant stem.
2. Use coffee grounds as a mulch and fertilizer
You can add coffee grounds straight onto beds where acid-loving plants will appreciate them.
Coffee grounds tend to be neutral or slightly acidic in their ‘raw’ form. Using them on their own without added compost or leaves needs to be done carefully and will only help your acid-loving plants. Roses are in this group, as well as azaleas, rhododendrons and heathers.
Here are 5 different ways to do this:
- Make a coffee ground mulch: mix grounds with leaves and use this around your rose bushes.
- Make coffee ground ‘tea’. Add half a pound of used coffee grounds to a 2-gallon watering can and mix. Use one 2-gallon canful per mature rose bush.
- Sprinkle coffee grounds in small quantities around your rose bushes. Let the rain and the worms dig them in for you, to avoid disturbing shallow roots. If there’s no rain, use a 2-gallon watering can per rose plant.
- Add coffee grounds to the hole when you are planting acid-loving shrubs to kick-start growth.
- Add coffee grounds to a wormery. Worms love them, as you’ll see below.
Worms love coffee
Having lots of worms in the soil around your roses is a good thing. As worms travel, they create tunnels. These channels help to get water and air into the roots of your rose bushes. If you have compacted soil or poor drainage, worms are invaluable.
They also love to eat coffee grounds. The resulting ‘worm casts’ are full of nutrients that get plowed back into your soil, enriching it and helping plants grow bigger and better.
Best time to fertilize roses with coffee grounds
It’s worth getting the timing right with coffee grounds for roses. Too early or too late in the season and adding coffee grounds could cause your roses to grow at the wrong time, risking damage.
The best time to use coffee grounds for roses is spring. April or May are ideal when the leaves are out, and your roses are starting to grow.
Don’t add coffee grounds to roses after August because it will encourage new young growth which may not have time to prepare for the winter months ahead.
You’ll end up with black dead leaves and stems when the first frost hits. If this happens, remove all of the decaying material before the winter months really set in. The mature parts of the plant should survive; roses are hardy.
Coffee grounds for acid-loving plants
Did you know you can use fresh coffee grounds in the garden too? These are more acidic than used coffee grounds. Sounds a bit extravagant, doesn’t it?! But you might have some old ground coffee in the cupboard that you don’t like. Acid-loving plants will love it though.
Roses grow best in neutral to slightly acidic soil. If you don’t know how acidic your soil is, you can buy an easy pH soil tester kit.
Hydrangeas, azaleas and rhododendrons are partial to fresh coffee grounds in the flower garden. In the vegetable garden, your radishes, carrots and blueberries will appreciate a sprinkle of ground coffee – but your tomatoes won’t, so keep that caffeine kick away from them.
Coffee grounds for roses: 3 top tips to take away
- Coffee grounds are good for roses, as long as they are used at the right time of the year and in the correct quantities. A good rule of thumb is half a pound of used coffee grounds to 2 gallons of water per rose.
- Use coffee grounds for roses when your plants start to grow in spring. The nitrogen will give them an extra burst of energy. April and May are ideal.
- Don’t use coffee grounds for roses in late summer or autumn. It may encourage growth just as the weather gets colder, which could mean parts of the plant start to die.
Use our easy methods above to make sure you are giving your rose bushes just what they need.
And if you have lots of coffee grounds to use up, think about what other acid-loving plants in your garden might like a boost, such as rhododendrons and azaleas.
In conclusion: don’t ditch the grounds; they are useful!