Robert Cecil and the Gunpowder, Treason and Plot

Cecil was a consummate plotter who undermined enemies and helped his supporters, he himself wrote:
"I spend my time in sowing so much seed as my poor wretched fingers can scatter, in such a season as may bring forth a plentiful harvest. I dare boldly say no shower or storm shall mar our harvest except it should come from beyond the middle region."
This was written just a fortnight before the discovery of poor Guy Fawkes. What does it mean? It is ambiguous, which is probably what Cecil wanted.
I think it is a coded message proclaiming that nothing could stop his plot from succeeding except if those in his service, in the Midlands bungled their part; that is failed to kill all the Catholics hiding in the house.
This must surely refer to the assassination of all those Catholic nobles who fled London. If they were dead, they could not protest their innocence.
The sherif's men ambushed and destroyed anyone who might have told the truth. Might those 'plotters' have set the record straight?