one of the leaves on seedling in a polytunnel has shrivelled, discoloured, and dried up. not feeding nutes at this time. soil is simple potting compost. what is be the likely cause, and how can it be brought back to health and prevented in future?
That's a cot leaf, it's job is done. All of them will eventually do the same thing, as will your single point leaves just above them. Completely normal and unpreventable.
