My Norfolk Island Pine has been growing unremarkably indoors for over 5 years. This mushroom was found tonight in the pot...it wasn't there 8 hours ago. It appears to have a greenish tint. Ideas on what kind of fungus it is and WHY it suddenly decided to grow in this medium?

I'm not sure what the question is: Why are you growing a mushroom? Why is it greenish?

Mushrooms feed on decomposing organic matter in the potting soil. Its greenish because that's the color of that type of mushroom.

I have edited my original question to include more information. DaisyI should know that I am not purposely growing a mushroom: it just appeared. We have a mushroom book and cannot find info on anything like this.

Could be spores in the air, one of my container pots out side has similar mushrooms that appeared after heavy rain. Has your soil been wetter than normal?

Christine: soil not wetter. Wondering if the use of MiracleGro might have contributed...never used a fertilizer on this plant before. Thanks for your response.

Its most likely a Yellow Houseplant Mushroom (Leucocoprinus birnbaumii). The spores come with the potting soil or float in. They range in color from pale like yours to bright yellow.

This is time of year for fungus to produce their fruiting bodies. The spores or mycelium is in the potting compost. They are harmless and you can simply remove the 'mushrooms'.

I looked up Leucocoprinus birnbaumii it is a species of gilled mushroom in the family Agaricaceae. It is common in the tropics and subtropics, but in temperate regions frequently occurs in greenhouses and flowerpots, its common name of flowerpot parasol .

Daisyl is right. It would be interesting to let it continue to grow . I had a lot of them growing in the greenhouse pots .

In my neck of the woods ..... literally..... they grow everywhere. Have had them growing out my wooden garage doors.UGH !

Welcome to "The World of Decomposition!" Mushrooms feed on dead and decaying matter. Just like Daisyl said. Certain mushrooms have seasons of abundance, others can be found on a year round basis.
The get their nutrients from the dead and decaying material that they feed on. Miracle Grow has nothing to do with it.

I agree with Sue. The mushroom spores are in the potting mix. When the potting mix is kept constantly moist, then the mushrooms will pop up seemingly out of nowhere. Beneath the surface, you will probably find a thin white root system that may produce other mushrooms.

They are not a problem to your plant or to you unless you decide to eat it - toddlers beware!

Remove the surface soil and any roots that you find. Keep the potting mix drier in the future. Use a sterile, soilless potting mix in the future.

If you want to get rid of them (I do because they smell really good and I have a really dumb cat), pull them up and sprinkle the surface of the soil with cinnamon.

Daisyl......what does the cinnamon do? I use cinnamon to keep ants away they won't cross it.

Cinnamon is a natural fungicide. I use it on seedlings (after they germinate - the cinnamon will prevent germination) to prevent damping off. Also when I repot orchids and have to cut roots.

There are a lot of recipes to make a spray but the shaker works just fine.