This morning, at about 11am, I went outside and found white fuzzy patches growing on the exposed soil of my lawn in a shady spot (in north-west England). It does not appear to be on the grass itself. See attached images. On closer inspection, it was also present on the soil under the grass in the non-shady non-exposed spots. I've searched the internet and this stackexchange, and have come across several white growths on soil, but nothing looks quite like this. I'm assuming it is some sort of mould or fungal growth. I'd like to know what it is, whether it is harmful, either to the grass or to a child, and whether it will go away on its own or if there is something I can do to treat it.

Some background: I recently thoroughly dethatched the lawn with a manual rolling scarifier as it had a significant thatch (and probably moss) problem. I applied EVERGREEN NO MOSS NO RAKE lawn feed at the recommended rate with a hand-held spreader, as well as lawn seed (various varieties left over in old boxes, maybe up to a year old), and then treaded and watered it in. I then watered with a sprinkler for about 20 minutes a couple of times a day. This was exactly one week ago. The grass and soil got quite wet, and I'm thinking it might not have needed the extra water, but I was worried about the soil drying out (it had been very dry prior to the overseeding) and causing problems with the new seedlings.

white fuzz on soil under grass

Thanks for any advice!

1 Answer 1


The white fuzzy growth is fungal hyphae. I can't quite tell from the photo (even under magnification) if its clustered over undissolved granules of moss killer/feed, or even over seed you may have laid - excessive amounts of granular products, under very damp conditions, do sometimes grow this type of mould over the top. It may also be a side effect of the product 'eating' the moss. I note you say you spread seed - if you did that just after using the mosskiller/feed, it may be that the seed will not germinate - it is usual to leave a gap of 4-6 weeks (depending on the product used) before seeding after using similar products, so the hyphae may be associated with seed going mouldy. I don't think it will cause problems to the grass that's growing there already.

  • Thanks! Is it possible to tell the type of fungus? Doesn't seem to be clustered around granules or seed. I wondered about the product eating moss leaving residue, but I would have expected to see remaining moss. Shame if seed doesn't germinate! I did some research before, and saw varying advice re: timing/ordering. It's not a ferrous sulphate based, and nothing stopping germination. e.g. see lawnsmith.co.uk/buying-guides/…: "For convenience apply the seed and fertiliser on the same day but never feed before seeding.". Time will tell!
    – grassnoob
    Commented May 3, 2020 at 18:27
  • As its just fungal hyphae (sort of strands or fuzz) it'll probably just disappear over time - it usually appears over a pile of wet dead leaves or something that's rotting down, even i you can't see what that is. It might develop as time goes on, though slime moulds and the like don't usually start like this.
    – Bamboo
    Commented May 3, 2020 at 18:37

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