OMG I think I’m being invaded, but I don’t recognize the enemy. Please help. This stuff is spreading. It s growing on the surface of my pots and on the top of the soil. I’m feeding with organic bloom food and bat guano in tea bags. I am already treating preventatively with Thiophorate-methyl and Imidaclopridl-methyl.
I looks like precipitated mineral salts(PMS) to me–it could be mold I guess. If you scratch it and its grainy and tastes like baking soda it is probably PMS. You could be watering with very minerally water, if so you will have find a different water source.
Looks like crystals to me based on color, shape and location. I wouldn’t taste it. Crystals should dissolve (at least mostly) if you scrape some off and put it in a glass of water. Mold won’t really dissolve and will be squishy and floaty. Bugs wouldn’t accumulate on the pot edge like that. I’ve had crystals like this before so I use stored rain water as much as possible. In addition to the tap water, fertilizer and salt in the air (in your location) might also contribute.
Wow, you sure have a lot of that stuff. Crust and James said it well. If it’s crunchy, that suggests an accumulation of salts. If it’s soft, that suggests mold.
Did the white appear quickly or over time?
In general, is the water where you live hard?
If it’s salts, it could be worth figuring out where the salts are coming from as too much salt can harm bonsai. Flushing with distilled water can help wash away accumulated salts, but if the salt continues to accumulate, intervention may be required at the source.
I did the water test suggested above. It appears to be mold. In water, the stuff got squishy. It didn’t really desolve unless I rubbed it between my fingers. Also, I live in San Francisco which I’ve been told has good water. I only have two trees with the problem thatnI can tell. Theses trees have only been in these these pots for a few weeks. The pots are brand new, but I did get both of them from the same potter in Slovakia. Is it possible this stuff came with the pots?
Great, that narrows it down. And yes, the water in SF is pretty good. Has the tree/pot stayed fairly moist in the past few weeks? I’m not used to seeing so much mold unless there’s a lot of water around - it appears the conditions are perfect for it. I’d start by making sure the tree gets as much sun as possible and dries out a bit between waterings.
It’d be interesting to hear if the potter has a similar problem in Slovakia.
I have never ever heard that a new pot could carry fungus–it is counter intuitive to how those things work. I say it still looks very much like a precipitated salt of some kind. Scrape some off and put a small amount of vinegar on it–if it fizzes then it probably is.
Thanks for all of your input. I’ve moved the pots to a location with better air circulation. The stuff seems to be dying back.