Weird Fungus in Pots?

Question

I have a number of large potted plants on my patio. They were repotted with potting mix over a year ago. Just over the last few months I have been emptying my coffee grounds onto them. The plants are flourishing, however, they have started growing several sorts of really weird fungus - white toadstools and a hideous bright yellow fungus - growing out of the drainage holes. What on earth is in the coffee grounds to do this ? Should we still be drinking it ! It seems odd that, if the spores were in the potting mix, they have only started growing just recently. Any ideas ? And, other than repotting them all, how to get rid of the stuff? It is freaking me out a little. I have rather gone off coffee lately !

Answer 1

Hi Cresta -

Kikkaz has most of the idea right - but, I dont believe it is a serious one or one to be alarmed over your own health about. The plant's health is a different matter.

Fungus spores - and lots of other micro particles - live everywhere and are in the air, water, soil - EVERYTHING! When you find mushrooms and fungus growing onto any medium (such as your potted plant) they have just found the proper growing medium for their own needs. Remember, things like mushrooms also have their own living requirements. I would venture a guess that these plants are very rich in organic matter (such as your coffee grounds), they are kept pretty moist and cool or somewhat shady. Voila! You have conditions to grow mushrooms and fungus.

I wouldnt be so alarmed, really - particularly over your own well-being and the coffee you drink - they really are completely unrelated to the health of your plant. If it disturbs you, cut back on the watering (to killl off the fungus) and do not add additional organic matter (particularly being it is decomposed - such as the grounds); if you feel the plant is suffering because of the added neighborhood of the mushrooms - or, it just really annoys you: then repot the plants with clean soil

Best of luck,
Chris

Answer 2

You are correct in saying that the coffee grounds are causing the problem, its not a good idea to be adding anything like that to your potting mix.
The fungus is not a good sign, and could possibly kill your plants in the long run I am not sure why you would want to put your coffee grounds in your pot plants, that's a new one to me. Remove all of the old potting medium and replace with a new mix.

Answer 3

We can often be tempted to add coffee grounds-left-overs or used tea-leaves into our plant's soil thinking it will supply additional nutrients and they do EVENTUALLY...but first they must decompose. Pouring left-overs directly from cup to plant, (specifically potted plants) doesn't have the same effect. The plant cannot directly process the fresh additive. It's in a form it cannot absorb and may actually be damaging it.
The fungus is due to a kind of chemical reaction it has to the forced-feeding it's being put through. The plant and therefore the soil it feeds on is just excretiating what's not needed or potentially damaging to it's health and survival.
I know we may think that organic additives must be good for our plants in general, but in large amounts, just sprinkled continuosly on our plants top-soil, faithfull in the idea that it must do them good, just doen't work and does more damage than anything else.
If you want to use your coffee or tea left-overs to good effect, you need to allow for decomposition before including these to compost/soil before adding them to a plant....besides, maybe you're directly adding certain nutrients to your plant which it may detest. ...acidity etc. You need to find out what nutrients your plant prefers before adding heavy loads of one particular chemical make-up which might unbalance it's necessity.

The fungus you see (sometimes at the bottom of the pot, sometimes on the surface top-soil) is a sign to stop whatever you're adding...watch and let the plant tell you what it wants!

Answer 4

Take a walk in the foest and you might notice that little toad stools, fungi and moulds abound - especially in damp areas.
Remove them if they are bothering you and slow down on the watering.
As for the coffee grounds - they will draw nitrogen out of the soil as they break down and will also lower the Ph of the soil. Mosses, moulds, fungi and toadstools all love acidic soil.
So I suggest that you safe the coffee grounds for the compost or use it in the garden where it will not be so concentrated.