After a particularly wet winter, you often notice small mushrooms growing on the top of the soil in plant pots. Most people want to know if they are poisonous and more importantly, how to get rid of them. Read on to find out why mushrooms are growing in your plant pot and some suggestions to banish them for good!
A few facts about mushrooms
Mushrooms are the above-ground, visible section of the mycelium root strand, which is a long, thin, underground string that mushrooms use to grow. In the wild, mushrooms thrive in damp environments like fields and woodland. The wet soil in a plant pot provides near-perfect conditions for fungi to grow.
The fungus may have arrived because the wind blew the spores there but it may also have been introduced by contaminated soil. Using animal manure is a common reason for the appearance of fungi. Occasionally, spores can be introduced after a day in the countryside when a spore attaches itself to your clothing and falls into a pot in the garden. Contaminated soilless mixtures can sometimes contain the spore of fungi.
Once the fungus is introduced, a mushroom may appear in damp conditions if there are enough nutrients for it to grow. The spores are produced in the underside of the cap of the mushroom and they can be blown far away from the pot they are in. So understanding what these mushrooms are like can help you to banish them forever.
How to get rid of mushrooms in flower pots
- Physically remove the mushrooms. Use gloves in case it is a poisonous variety. It’s important to remove the cap but also the mycelium, (the root of the fungus) in order to eradicate it permanently. The root grows at least 2 inches deep so when you remove the cap, dig a little and pull up the root too. Discard the mushroom and the roots so they do not find their way back into your soil again. Allow them to completely dry out first if adding them to your compost heap.
- Remove any rotting leaves. In the autumn, clear any fallen leaves or plant debris to discourage fungus from growing in the first place.
- Re-pot the plant. Adding new soil means that the mushrooms will also disappear. Wash your plant pot using hot, soapy detergent. Scrub it hard and then rinse with clear water. The next step is really important! Make sure you allow it to dry well, before adding any new soil. Fungi thrive in moist, damp soil so if your pot is clean and dry, even if spores find your pot, they will be less successful.
- Do not over-water your plant! Fungi do not naturally occur in dry soil. Moisture is the key ingredient so if you water sparingly, they have less chance of developing. You could try watering a small amount that only reaches the top inch of the pot, but this will not suit all plants. Some plants need a good soaking, so check the watering requirements before you deprive the plant of generous moisture.
- Empty the water saucer. Plants are often placed on a saucer or tray to catch excess water. Make sure you empty the saucer quickly and don’t let the pot sit in a wet tray for a long time.
- Use chemicals (fungicides) to kill them. I don’t like using chemicals at all. However, this could be the last resort if you have pets that like to chew mushrooms or small children who may be tempted to pop them in their mouths. Just be careful using them, use gloves and be careful when disposing of any leftover chemicals.
Are mushrooms in plant pots poisonous?
Some mushrooms that grow in plant pots may be toxic if consumed. Here’s a list of poisonous and inedible mushrooms that are commonly found in the UK:
These bright mushrooms are probably Leucocoprinus birnbaumii and they are poisonous. They have yellow coneheads and yellow stalks, which become increasingly dense in colour as they age. Do not eat these! They can cause diarrhoea, vomiting and fever, and in extreme cases death. Make sure you remove and discard any that you find.
Panaeolina foenisecii or the brown mottlegill mushroom is very common in Kent, where I live. These mushrooms are inedible.
Panaeolus semiovatus, also known as the egghead mottlegill mushroom is inedible and can cause digestive upset.
Are mushrooms in pots bad for the soil?
It is a commonly held belief that fungi remove all the nutrients in the pot in which they are growing. Generally, fungi improve the soil by breaking down other plant materials. They are not bad for the soil. In fact, they probably improve the quality of the soil overall. Mushrooms enjoy moist environments with plenty of rotting plant material, like fallen leaves or decaying wood.
If you want to keep mushrooms out of your pot, remove any rotting leaves, do not water them too frequently, and change the soil every few years.
Common indoor mushrooms found in houseplants
If you’re a proud houseplant parent, you may well have noticed some rogue mushrooms appearing in the soil from time to time. These are some of the most common culprits:
These small, pale yellow mushrooms are the most likely to be spotted growing amongst your indoor potted plants. They begin as small round balls which grow to between one and three inches tall. These are saprotrophic mushrooms which feed on dead organic matter, they won’t harm your plant.
Although these mushrooms aren’t parasitic, they will spread and they can cause digestive problems if ingested. Mushrooms can be tricky to eradicate so it’s best to change the potting soil and wash the pot thoroughly before repotting the plant.
These mushrooms are very common in potted plants and greenhouses. Also known as pleated ink cap mushrooms, they feed on dead organic matter and won’t harm your houseplants.
These pretty, grey mushrooms grow to 5-6cm in height and are usually found growing outside in short grass, a batch of infected compost is the usual reason for them cropping up next to your houseplants.
Why are mushrooms growing in my plant pot?
Mushrooms can grow in plant pots for several reasons; the most common one is an infected batch of compost. Mushroom spores can survive for many months, waiting until the conditions are right for them to grow. Overwatering and warm temperatures are perfect conditions for mushrooms to thrive and they’re also more likely to sprout in areas with little natural light and poor airflow.
Should I remove mushrooms from my houseplants?
The mushrooms you’ll find growing in your houseplant compost are unlikely to harm the plant, however, they are likely to spread. Whether you remove them or not is up to you! You might want to remove the mushrooms if you have young children or pets who could accidentally ingest them.
What should I do with mushrooms growing in potted plants?
Since mushrooms that grow in houseplant pots are harmless, you can simply leave them alone. If you’d prefer to remove the mushrooms, try to do as soon as they appear before the gills open and they’ve had chance to spore. If this doesn’t work, the best way to remove mushrooms for good is to repot the plant, completely replacing the compost. You may need to do this more than once.
You can also spray a fungicide treatment onto the soil, although you will need to repeat the process.