Have you heard of coffee grounds being great for plants, and wondered about adding some to your Monstera? There are a lot of myths about miracle cure-alls for plants online, and it’s important to check before you start adding things to the soil.
Coffee grounds may offer some nutritional gains to the plant as they decompose, adding nutrients to the soil, but there is currently little scientific evidence to support this. Some people also claim that coffee grounds improve the soil structure, but again, there is no evidence of this yet. Adding coffee grounds could attract fungus gnats, and the larvae of these insects are harmful to plants.
Why Might Coffee Grounds Be Good For Monsteras?
Coffee grounds are said to be good for Monsteras for two reasons: they add nutrients and improve the soil’s moisture retention properties. Some people also say that they can help Monsteras resist certain diseases, but it isn’t clear whether this is true.
Do Coffee Grounds Add Nutrients?
It makes sense that people think coffee grounds will add nutrients to the soil. Used coffee grounds look a lot like rich, dark, fine compost, and they are made up of organic matter, so it seems logical that they would be helpful.
They are also a great addition to a compost heap because they are a favorite food of worms, and this helps to enrich the compost and speed up the decomposition process. This leads people to think that they must be particularly valuable in terms of nutrients for the plant.
It’s possible that coffee grounds do give your plant a boost, but this would occur slowly as the nutrients break down into the soil, and there is not yet any evidence to back this up (although few studies have been done, so the lack of evidence doesn’t prove anything). Like adding any fertilizer, it probably does have long-term benefits.
There is plenty of anecdotal evidence that plants grow better when coffee grounds are added to the soil, but given how difficult this is to measure and the risk of confirmation bias, this evidence should be treated with caution.
It’s hard for people to accurately assess whether their plant’s growth has improved, and they may believe they are seeing a growth spurt where there isn’t one, or where the growth spurt is due to other factors (e.g. more sunlight, changing seasons, etc.).
Before they have broken down, coffee grounds will not enrich the soil, and even once they have broken down, they will not enrich the soil in a way that is notably more powerful than fertilizer.
Overall, coffee grounds will add some nutrients to the soil in your Monstera’s pot, but it is unlikely that this will have a noticeable effect on the plant.
Do Coffee Grounds Improve Soil Structure?
Coffee grounds are also said to improve the soil structure because they are fine and they can absorb water. This claim also isn’t backed up by science, but it may be true in some cases.
However, if the soil in your Monstera’s pot already has a fine texture and holds onto water well enough, you might not be doing yourself any favors by amending this. You may alter the water retention properties of the soil, which could lead to over-watering the plant.
Adding a few coffee grounds around the surface of the pot is unlikely to make much difference either way, but be aware that you may be able to get the same result by adding a bit of perlite to loosen up the soil.
Do Coffee Grounds Help With A Monstera’s Disease Resistance?
Few studies have been done on this, but there is again little evidence that coffee grounds can improve a Monstera’s ability to fight off certain diseases. It is possible that they do, but we just don’t know yet and have nothing except anecdotal evidence to go on.
Activated charcoal is used for the same purpose, and may be a preferable option if you are worried about diseases because it doesn’t have any of the disadvantages associated with coffee grounds (which we will cover shortly). Adding a layer in the bottom of your Monstera’s container can help with watering issues, and could help to fight off mold and insect infestations.
If you choose to, you can add coffee grounds to test the veracity of these claims yourself, but first, let’s look at what the drawbacks and dangers of using coffee grounds may be. You will then be in a good position to decide whether to proceed or not.
Why Might Coffee Grounds Be Bad For Monstera Plants?
Coffee grounds might be bad for a Monstera because they add a layer of rich, decaying matter to your plant’s pot. This is essentially food for many things and will tempt unwelcome visitors to the container. Again, there are a couple of issues: fungus and fungal gnats.
Firstly, fungi may arrive. These will happily feed on the leftover coffee grounds, as they provide the decaying nutrients that fungi need to grow. Indeed, used coffee grounds are often utilized specifically for growing fungus.
The fungus may not go on to attack your plant, but you still don’t want them to grow in your Monstera’s pot. They may spread, and if your plant becomes sick and starts to develop decaying tissue for other reasons, they almost certainly will start to attack it.
You don’t want fungi in your Monstera’s container, and coffee grounds are very likely to attract them. It is better to keep your plant’s container free from this kind of organic matter so that it can grow in a healthy, clean environment. If you do see signs of fungus appearing, consider repotting your plant.
Secondly, coffee grounds and the mold that appears on them will attract fungus gnats and fruit flies. Both of these are harmless to a plant in their adult form, but they are unsightly and annoying, and fungus gnat larvae are far from harmless.
Fungus gnats are tiny flies that will dart about the container and feed on the molding coffee grounds as they break down. They are attracted to almost any kind of fungus, so if you introduce rotting matter to your plant pot, these gnats are very likely to appear.
The fungus gnats will lay their eggs in the coffee grounds, and the larvae will burrow around, eating the decaying matter until there is none left. At this point, they will move onto the plant. Although they prefer decaying food, they will attack your Monstera if there is no other food available.
Because they are in the soil, they will often target the plant’s roots. This means you won’t be able to see the damage, and it also seriously undermines the health of your plant. The roots are possibly the most important part, and if they are being damaged, your Monstera will get sick fast.
Fungus gnats can be a real challenge to get rid of, and you will probably have to repot your Monstera once they have taken hold of the soil.
You can also try adding a layer of gravel to the surface of the pot to stop the gnat larvae from hatching into flies, as this will break the cycle, but it’s better not to invite them in the first place. Providing decaying matter in your plant’s pot can therefore be problematic.
Are Coffee Grounds Dangerously Acidic?
There is quite a bit of debate surrounding the acidity of coffee grounds. Some people say that they will make the soil dangerously acidic and this will kill your plant, and again, there is anecdotal evidence to suggest that this happens occasionally. However, this is fairly unlikely in most situations, as long as you aren’t applying excessive amounts of coffee.
The acidity of coffee grounds can vary a lot, but most coffee grounds are only mildly acidic, and will not have a big effect on the pH value of the soil unless you add them in large quantities (e.g. as a mulch).
Many people estimate the acidity to be between 6.5 and 6.8 in most cases, and with a neutral pH value being 7, this is not strongly acidic.
A small handful of coffee grounds is unlikely to have an impact on your plant, although you should be wary of adding large quantities.
It is also worth noting that coffee grounds will contain at least some caffeine, and this can inhibit growth in some plants. Again, this will likely have little effect on an established, healthy Monstera, but it may still be better to avoid adding caffeine to the container if you can.
Adding coffee grounds to your Monstera’s pot can cause some issues for your plant, as it may invite fungal infections and fungus gnats, which could both be harmful. It is possible that coffee grounds will provide a nutrient boost, but this can also be achieved by adding fertilizer.