I've planted Basil (from a pot) outside and it's been very wet in the last few weeks. The plant has now got these grey spots on it. What is wrong with it?
That is leafspot, or pseudomonas cichorii. It is a bacteria that lives in the soil and infects the plant when soil is splashed onto the leaves
There is no cure for bacterial leaf spot for homeowners. Growers could use streptomycin or copper maneb but I would not use these for something I was going to eat.
Here are some recommendations: