Coffee Grounds In The Garden

For coffee lovers there’s that age old conundrum - what to do with all those leftover coffee grounds. Over 3000 tonnes of coffee grounds are produced each year in Sydney alone and most of that ends up in landfill. Not cool.

Thankfully coffee grounds are one of the most useful waste materials around. They’re full of nutrients and when you add an organic material to soil (like coffee grounds), it improves the drainage, water retention and aeration in the soil. You can even change the colour of your flowers with coffee. How cool is that?

Here are a few things you can do with your spent coffee grounds other than put them in the bin.

Add them to your compost

When you add used coffee grounds to your compost and then use that compost on your garden, it enhances the soil nutrients and helps keep your garden resistant to pathogens (nasty little viruses that cause disease). Also compost doesn’t really smell great at the best of times and coffee is a natural deodoriser so there’s the added benefit of making your compost heap less stinky.

Make a leaf spray with them

Just add two cups of coffee grounds to a five gallon bucket of water and let it rest overnight. Then pour it into a spray bottle and use it as a liquid fertiliser on the garden and on your pot plants. Sometimes we forget that leaves need a little loving too!

Use them as a general fertiliser

Mix your coffee grounds in with your mulch or potting soil to add growth promoting enzymes and minerals. Tip: Don’t use coffee on its own. It tends to clump together and creates a drainage barrier. Always mix large amounts of coffee grounds with other gardening materials to stop your plants from suffocating.

Sprinkle them around the base of your plants to keep the creepy crawlies off

If you spread a thin layer of coffee grounds (not too thick or you risk drowning or suffocating your plants) in your garden beds, it may help to keep slugs and snails from having your plants for lunch. Tip: Apply coffee grounds to the area regularly as rain will wash them away easily and soil will absorb them over time.

Do magic colour changing flower tricks with them

Do you know why some hydrangea flowers are pink and some are blue? The higher the alkaline level in the soil, the more likely pink hydrangeas will appear. So if you add your coffee grounds to pink hydrangea soil, they might just turn blue because you’re making the soil more acidic. Tip: This works better in pots and it’s easier to make pink hydrangeas turn blue than the other way around because it’s easier to add to the acidity levels of soil than it is to lower them.