Bottom-of-the-table Spalding could not even be saved by the wet weather as they suffered another defeat.
Warren Nel scored 77 out of 184-8 at Boston, putting on 53 for the third wicket with Brandon Andrews.
Andrews then dismissed Boston’s top three batsmen for 24 and the fourth wicket fell on 58.
Tom Baxter joined Fayadh Haffejee in a 116-run partnership before Haffejee was out for 86. Baxter went on to make an unbeaten 51 and take his side to a five-wicket win.
Bracebridge Heath claimed the championship on a rain-affected afternoon which saw four games abandoned.
The league leaders had only 15 runs on the board at Lindum when the game was called off while second-placed Grantham had reached 70 without loss when their fixture at Market Deeping came to an end.
Bourne were 143-3 against Grimsby when the match was abandoned.