Did you know that coffee grounds can help you fertilise plants? Maybe until now you have always thrown them away, precisely because you were not aware of this ingenious and ecological way of recycling them.
That said, it is true that not all species benefit from this novel fertilisation system. That is why we decided to tell you which plants should not be fertilised with coffee grounds… and which ones should!
Which plants should not be fertilised with coffee
Coffee grounds are an ecological resource rich in minerals such as nitrogen, calcium, potassium and magnesium, which can work wonders for the soil. However, not all plants like the acidity that coffee grounds bring. If not used carefully, soil acidification may be harmful for some species. It is important to know which plants to avoid fertilising with coffee grounds so as not to compromise their growth.
For many plants, the acidity of coffee grounds is a challenge. Plants that prefer more neutral or alkaline soils cannot tolerate excessive acidity and may suffer if fertilised with this beverage. Here are some plants that you should avoid fertilise with coffee grounds:
- Fruit trees: Plants such as apple, pear, and cherry trees do not tolerate overly acid soil. Coffee acidity could prevent good fruiting, damaging the roots and compromising the growth of the trees. These trees prefer more balanced and neutral soils for optimal fruit production.
- Indoor plants: Some indoor plants, such as ficus and dracaena, are sensitive to acidity. Coffee grounds degrade slowly and can accumulate, compromising the health of the roots, making the soil too acidic for these delicate plants.
- Broccoli: Like other cruciferous vegetables, broccoli does not like soil acidity. The lowering of pH caused by coffee grounds may obstruct the healthy growth of the plants, reducing the quality and the quantity of the harvest.
- Tomatoes: Tomatoes are very sensitive to soil pH. Soil that is too acidic could interfere with the absorption of vital nutrients, compromising the health of the plants and the fruit quality.
- Sunflowers: Sunflowers, despite being quite resistant, do not like when the soil is too acidic. Coffee grounds may slow down its growth and reduce fruiting.
- Radishes: Radishes prefer a more neutral pH. Excessive acidity from coffee grounds could slow their growth and reduce the quality of the harvest.
- Carrots: Carrots are also unsuitable for coffee grounds, as they could compromise the quality of the tubers and slow down growth.
- Peppers: Peppers do not tolerate acidic soil. If fertilised with coffee grounds, they could suffer from an inability to properly absorb essential nutrients.
- Lettuce: Lettuce grows best in soil with a neutral pH. Coffee grounds, with their acidity, can hinder leaf growth, making the plants more bitter and less healthy.
Plants that benefit from coffee grounds
While some plants do not tolerate the acidity of coffee grounds, others benefit greatly from them. Acidophilic plants love soil with a low pH and adapt very well to fertilisation with coffee grounds. Here are some plants that love acidity and can thrive thanks to coffee grounds:
- Basil: This aromatic plant likes slightly acidic soils, so coffee grounds are perfect for promoting lush, aromatic growth.
- Berries: Blueberries, strawberry, and raspberries are acidophilic plants that benefit greatly from coffee grounds, which improve fruit quality and stimulate growth.
- Rhododendrons, azaleas and camellias: These garden plants thrive in acidic soil, and coffee grounds are an excellent fertiliser for stimulating abundant and colourful flowering.
- Hydrangeas: Hydrangeas can change colour depending on the pH of the soil. Coffee grounds, which acidify the soil, can be used to achieve more vivid colours in the flowers.
- Rhododendrons: Rhododendrons also thrive in acidic soils and benefit from coffee grounds, which promote healthy growth and abundant flowering.
Can coffee grounds be used to fertilise succulents?
The cultivations we have mentioned so far mainly involve people with a ‘green thumb’. If you do not have one, however, you should not necessarily think that this subject does not concern you: there are in fact plants that are also appreciated by those who do not know how to handle them, precisely because they are so easy to grow.
We are obviously referring to succulents, which are characterised by the fact that they require very little care and, as such, are perfect for those who tend to kill off any plant that has the misfortune to fall into their hands.
The reason we are telling you this is because, among the species we have listed to answer the question ‘which plants should not be fertilised with coffee grounds’, succulents are not included.
This means that if you have a cactus as a friend, you can safely fertilise it with the ‘waste’ from your favourite beverage. The coffee grounds will not only contribute to its growth, but will also aerate its soil, providing it with massive, healthy oxygenation.
But that’s not all: unlike the nutrients contained in chemical fertilisers, those in coffee grounds tend to be absorbed more slowly, resulting in their beneficial effects lasting longer.
That said, you should still use them sparingly. The amount of coffee grounds used as fertiliser should ideally represent no more than 20% of the soil mixture. Otherwise, in fact, the risk is to turn them into harmful substances, favouring the presence of mould and parasites that would inevitably end up ‘suffocating’ the poor plant.
As with everything, therefore, stick to the old adage of ‘cum grano salis’, using coffee grounds only from time to time and never neglecting the normal care that every plant needs.
Conclusion
If you’ve made it this far, you probably understand how useful coffee grounds can be, not only for your plants but also for the environment. Far from being considered ‘waste’, coffee grounds are an ecological resource that can enrich your garden in a simple and natural way. Next time you enjoy your favourite drink, remember not to throw them away: use them as fertiliser for plants that will benefit from them.
Not only will you be doing your plants a favour, but you will also be contributing to sustainable recycling that helps reduce waste. And why not take the opportunity to treat yourself to a few extra cups of coffee (in moderation, of course!), prepared with the right machine. Discover the perfect coffee machine for you, to enhance every sip and do good for the environment at the same time!
