Hi skaboo,
as ab stated earlier 'on the radio' is a term used by the daily mail quite often.
it is a indicator of 'sounds like'.
as you only hear things on the radio, 'recede' and 're-seed' sound the same. If you saw them written with your eyes. they would appear different. Hence 'on the radio' means 'sounds like'
go back = recede (to ebb)
broadcast is a method of scattering seeds, therefore to
re-seed = broadcast again (to sow seeds by scattering once more)
I have no intention of being smug or rude. I hope this may be of use to anyone reading this for future xword challenges as it does pop up quite often. (especially in the mail. : )