White fuzzy mold

[kenny_j]

I bought Sunshine Advanced mix #4 to pot up with this year. When I opened the bag I noticed a very faint layer of white mold on the surface of the compressed bale. I scraped off the surface layer and used it to pot up a month ago. No recurrence til thin mornining. Plants were out yesterday and got over wet when the rain came, but the soil was almost too dry just before that. Warm night in the garage and many pots have white fuzzy mold on the surface of the soil. I had wondered if the mold was part of the mycos or something else. Is this normal? or do I need to take action. I have a proper H2O2 mix in the spray bottle now-1 TBS/cup of H2O. Any advice will be appreciated.

[RootLoops]

it could be from the mycos, does it stay white or turn green at some point? green mold will start off white and turn green within a couple days. most myco formulas contain trichoderma(green mold) do the plants seem to be doing worse? do you have any pics?

[RayR]

You can't see mycorrhizae, besides they won't grow other than in association with the roots of a living host plant. The white mold is just a common saprophytic fungi that is feeding on the dead organic matter in the mix.

[kenny_j]

The plants are fine now. Will the mold be a problem to the plants is the real question. Do I need to treat it?

[RootLoops]

those mixes often contain more than just mycorrhizal fungi, trichoderma being the one most added, i've seen it in just about every one i've bought, that's what i meant by mycos not the ones that live on the roots. trichoderma can eat a lot of other fungi that may be harmful. as for if you should kill it you'd have to identify it to know if it is bad or not. if the plants don't seem to suffer it may not be worth treating it

[Cole_Robbie]

I think we just had this discussion a couple of weeks ago. The white stuff that looks like a mold is a lichen. It's harmless.

[RayR]

The white saprophytic molds are no danger to the plants since they are not parasitic to living tissue, they only feed on dead organic matter. I often see when I am doing germination testing on old seed that if the seed is dead white or black molds will readily grow on them but the viable seed they don't even touch.
The only problem with white molds on top of the soil is that if the mat gets thick enough it can inhibit air flow to the roots. Just scrape the top surface with the mold off and put a thin layer of sand, bird grit or DE on top and that is usually enough to keep the mold from growing back in any major way.

Trichoderma are very interesting fungi, there are many species of Trichoderma and the type you may see above ground growing on dead wood or mushrooms are usually green in color. The dark green growth that appears on top of potting soil is more often green algae and not Trichoderma.
There are few species of Trichoderma that are capable of growing underground and typically grow on and around plant roots feeding off of root exudates and any invading fungi or oomycetes species that comes in their territory. These are the species that are beneficial as biocontrol agents, they directly protect the roots from pathogens as well as inducing acquired resistance pathways in the plant to pathogens. They also have a positive effect on plant nutrition and growth.

Plant-beneficial effects of Trichoderma and of its genes

[kenny_j]

Thnx for the inputs/ I sprayed it lightly with H2O2 before I read the last couple, wish I had let it be on at least a couple just to see. Second yr in a row I've had it.