No it is fine. Some of the wood in the mix was not composted enough. So the fungus found some food. No big deal. Not mushrooms but fungus in your potting soil namely mycorrhizae, is a tremendous benefit to root growth. I add fungus to all my vegetables and all plants in containers. Everybody should be using mycorrhizae specific to your plant type. They help the roots absorb nutrients more effecienly. Even expand the ph range plants can uptake nutrients. Make nutrients in the soil availablee that otherwise would not by expanding root growth to more of the soil.
Disease and pathogen suppression is another benefit for a mycorrhizal plant. Mycorrhizal roots have a mantle (a tight, interwoven sock-like covering of dense filaments) that acts as a physical barrier against the invasion of root diseases. In addition, mycorrhizal fungi attack pathogen or disease organisms entering the root zone. For example, excretions of specific antibiotics produced by mycorrhizal fungi immobilize and kill disease organisms

That's interesting - and sounds great! Thank you for the helpful info. Next time, I will leave them in, if it's just a few.

I looked at the plant again and even found some growing upside down, through the ends of the container! I tossed those, so they wouldn't block drainage. I only transplanted this a few days ago, just before the rainy spell, and it seems the roots have expanded quite a bit! I wonder if the mushrooms promoted that growth.

Good thing they are friendly mushrooms to balance the overwatering! Are they edible? I wouldn't want to try one, but in case they were ingested, would it be toxic? safe? hallucinogenic?

I planted some leaf lettuce seedlings in the top of the pot, hoping they won't be in competition with the mushrooms.

Be careful with overwatering in the plant spa particularly if you are using an off the shelf average potting mix. The water reservoir combined with a high perched water table(because of the dense potting mix) is a root killer. Especially if you have a young plant. The mushroom growing is a symptom of too much water obviously. That type of fungi is not beneficial like the root mycorrhizas though it does no harm either. By the way there are millions of species of fungi and thousands of mycorrhizas. Keep the saucer dumped out during periods of extended rain.
My only success with the plant spa and store bought potting mix is a fast growing annual that becomes somewhat rootbound and drinks water faster than you can pour it.
Best chance for success is a highly aerated potting mix that retains a low PWT such as the homemade 5-1-1 mix. Lots of info on this container forum on how to make it yourself.

Rebuilder, thanks. Out of curiosity, what was the annual that did well in that pot?

I dumped out the excess water on Wednesday - it was prob built up over a few days of rain, and have seen the odd tiny mushroom here and there since then.

I haven't watered since then - three days later - except for a tiny sprinkle to hold the soil together for my transplants. It only rained once, very lightly and for a few minutes - yet the soil in the container is still quite moist on top.

It's been humid, cool, and cloudy, but come ON, weather!

At least the leaves are looking good.

PS, for future reference is something like this better for drainage than traditional Miracle Gro potting mix?

http://www.midlandhardware.com/143557.html?gclid=Cj0KEQjwrqieBRCln82Rgufz7I0BEiQAPNjAI2Ks5r7vKwlPGZZqCM-sJXSc-ZK6UmRQq1YFrM5IHd4aAhJb8P8HAQ#.U8rhrPldWyU

Green Thumb's Moisture Manager Potting Soil.

It says it "slowly releases water". " Includes Canadian Sphagnum Peat Moss, Water Absorbing Crystals, Perlite, Time Release Plant Food, Gradually Releases Water & Assists In Maintaining Consistent Moisture Levels Longer Than Ordinary Soils."

At the moment, I don't have the resources or need to make a batch of my own mix, maybe next year.

I'm not familiar with a plant spa, but I had to return most of the organic top soil I bought this year due to a MAJOR mushroom infestation. The store allowed me to keep the used soil and I dumped it outside and had to toss all the plants in a trash bag.

It was explained to me that the bags I bought (about 10 ) had mushroom spores in them due to where the company picked the soil up. Yes, some twigs were in the bags... I also had bought 6 bags of organic compost and mixed them together...

It was freaking unreal... never had I heard of anything like this or seen anything like this.... every day THOUSANDS of new mushrooms in about 10 container plants. I kept picking the massive amounts daily... next day even 30 minutes later... massive amounts more grew. Every where reeked the smell of a mushroom. I couldn't take it... whether the soil was indoors or outdoors.

All of it I dumped... still mushrooms grow, but not the abundance as inside. LOL... I had it proven when I returned some of the bags... mushrooms were growing outside of the tops etc...

Most people say never use top soil for gardening especially container gardening.... eh... I have years experience. Don't degrade my lushest many years experience with great outcomes unless you've seen how successful I've been. I got some BAD bags from Lowes... organic they sold. I even have most of my current garden top soil with other mixes this year and are doing great. NO MUSHROOM SPORES!!!!!!!! woohooo!

The start of this was back in Jan or Feb of this year... I had starter pods for some seeds germinating. I posted pictures on here questioning it. Once those were big enough to put in their perm pots.... kapow!!!!!!!!!!! I was told the few mushroom species weren't' poisonous ... but no way could I find it safe to breathe their smell constantly. They fumed my entire place.

BTW... I've heard companies are suppose to burn the soil first to prevent this with a mushroom infestation and other soil bug infestations and diseases etc....
This is the only time this ever happened to me and that organic soil wasn't cheap. They only refunded me for all the soil and compost... I took a hit on seed cost lost and electricity and light bulbs... never the less... I'm certain the plants weren't happy to lose their life so quickly.

I absolutely do not mind an occasional mushroom... in fact I like having a few around.

natydoll,

I can't remember if it was a New Guinea impatien or the hybrid Sunpatien that did ok(not great) in the spa. I may have also had dragon wing begonias in one of those pots that did well.

Do not use the moisture retentive potting mix you linked. It uses the polymer crystals that will make it even worse. Again there may be some circumstances where one might use that type of mix and be semi-successful. One is a hanging basket with a coconut coir liner that breathes and evaporates lots of water from the sides of the basket in the summer sun. I have baskets like that in the full sun but my choice was to continue using the 5-1-1 mix and place a plastic liner with slits for drainage.
One other thought is that you could amend the media that you have with "soil conditioner" or "pine bark mulch" to add more aeration. In our region soil conditioner is made from pine bark as well. I live in the southeast and both can be found at all the big box stores and nurseries in the atlanta area. Some of the pine bark mulch is not good however. Right now the Timberline brand of mulch is good but the Evergreen brand is bad. Just yesterday I noticed the Evergreen pine bark mulch at Lowes had large bark chunks with lots of sapwood. There is considerable variation in consistency and quality depending on where you live. I have even seen considerable differences in batches at the same store a month later. Both brands can be found at some of the Lowes and the Timberline brand at Home Depot. Soil conditioner($2.60 for 2 cu.ft.) is more composted than mulch so it might be a little better than pine bark mulch. You could mix between 2 to 5 parts of conditioner/mulch to one part of your existing potting mix. It's also recommended to throw in a little dolomitic lime to offset the possibility that the conditioner/mulch has a low ph(maybe a 1/2 tablespoon per gallon). Usually it's the addition of peat moss when making 5-1-1 that requires lime(1 tablespoon per gallon). Soil conditioner/mulch is partially composted and has had time for the ph to adjust upward. You may not even need lime when mixing in with your existing media.
Best of success!
Tony