Well I'm racking the recesses of my (now rather old) brain - as far as I recall, this is a fungus of some sort, of the mushroom/toadstool variety, but I can't for the life of me recall it clearly. I believe its harmless, and is more to do with the woody litter in the growing medium than the plants themselves, but Seaburngirl may have a clearer, more informed answer.

I think that you are right, Bamboo, it is a fungus growing on the wood chips and harmless.

Though I'm not sure the wood chips are good as top dressing for the herbs - which I can't see, are these seed pots?

Thanks all, that refreshing. I was thinking spider eggs or something. I thought the samething about the wood in the soil. It the organic miracle soil in the bag.

Potting compost will not have bark in it... aha did you buy?