Patchy germination and worms.

Had fairly good germination but when we tipped out the pots that did nothing every pot had a huge worm sat near the bottom. I have never had this before just seemed odd.  Pots are in cold frame on the patio not direct on soil.

Ps I am sure I asked this question already so I do apologise in advance if indeed I am going mad. 

It was fat and very long one in each pot, it was in courgettes, cabbage, one lettuce pot that did germinate, loads of the horrible things. Will try and find a pot and photograph one.