Radish Problem

Ive had some radish's in the ground since the middle of march, bit slug eaten on top but no probs.  Loads of top growth but when ive pulled them (today) the actual radish is tiny, they ranged from pea to marble size.  Hardly worth the effort really although my OH loved them as they were extra hot.

Ive never had a problem with them before, what have i done wrong  :blink:

Interesting i didnt know radish' were that affected by weather.

Thank you