In an effort to keep things natural and sustainable, many gardeners are now moving away from chemical fertilisers, turning to DIY alternatives instead. There’s nothing wrong with this – a good homemade fertiliser can easily rival a commercial product.
That said, you do need to know what you’re doing when it comes to certain feeds. Using coffee grounds is the perfect example – it’s regularly touted as a beneficial soil amendment, but is it actually a good idea to use coffee grounds as a fertiliser for your garden trees?
The Benefits of Coffee Grounds as a Tree Fertiliser
Coffee grounds are packed with a number of essential nutrients. They contain high amounts of nitrogen, along with potassium, phosphorus, and a variety of micronutrients. That’s right, they offer the same nutrients that most commercial feeds provide.
Even better, coffee grounds release these nutrients slowly, providing a steady and consistent supply of feed to your soil and plants. Many gardeners find that coffee grounds also help to deter certain pests, particularly snails and slugs.
The downside to this is that coffee grounds are quite acidic. They’ll alter the pH of your soil, which could pose a problem for certain trees. Some thrive in acidic soil, meaning that coffee grounds would be perfect for them, whereas other need an alkaline mix, which is where coffee grounds could be detrimental. This makes it important to understand the soil requirements of the trees that you’re growing.
Trees That Would Benefit From Coffee Grounds as a Fertiliser
Fortunately, there are quite a few trees out there that do better in a slightly acidic soil. The Queensland Bottle Tree is one example, as is the Dragon Tree. Many fruit trees also prefer a small amount of acidity, including citrus trees, the Avocado Tree, and the Mango Tree.
For these trees, an alkaline soil mix prevents them properly absorbing all of the nutrients that they need. Using coffee grounds to add acidity to the soil can really boost their growth, so long as you use them in the right way.
How to Use Coffee Grounds as a Tree Fertiliser
It couldn’t be any easier to use coffee grounds as a tree fertiliser. Simply sprinkle them lightly onto the soil around your trees. Don’t dump in a thick layer – they shouldn’t make up more than 10% of the soil that your trees are growing in.
Alternatively, if you have more coffee grounds than your trees could possibly use, you could also compost them. Since they’re so nitrogen-rich, they count as a green material when added to a compost heap. However, again, do this in moderation so that your finished compost isn’t too acidic.
Used vs. Fresh Coffee Grounds
One final thing to keep in mind is the difference between used and fresh coffee grounds. Used coffee grounds are what you want. Fresh grounds are simply too acidic, and their high caffeine content could also negatively affect the health of your garden trees.
While fertilising your garden trees isn’t always necessary, people that do tend to notice a significant surge in growth after a few regular feeds. If you happen to have access to used coffee grounds, and are also growing trees that would benefit from a slightly acidic soil, then this is a great way to put what would have otherwise been a waste product to good use!