Upon winning the toss they invited Alford to bat and started well when Ian McPeake had Kelly caught by Shorthouse for three.
Howman and Bovey rebuilt as Sleaford’s bowlers struggled with footholes and conceded extras, but on 51 Howman (21) was stumped by Burford off Conor Harbron.
Bovey continued to play with care and reached a creditable 44 before becoming McPeake’s second victim.
The remainder of the innings revolved around White who put together a very good 48 before being caught by Harbron off Angus Youles as Alford were bowled out for 150 in the 43rd over.
McPeake took 4 for 32, Youles 3 for 20 and Harbron 2 for 22.
Sleaford’s reply began badly when Aayush Patel was bowled by Bennett for two, bringing Andy Hibberd to the crease.
Shorthouse (6) was then caught and bowled by Bennett (6 for 33), Burford went for 0 and Roberts for four as Sleaford slipped to 41-4.
Hibberd and Youles rallied to 82 when Hibberd fell to White for a well-compiled 48.
McPeake and Harbron went for 0 leaving Sleaford on the brink of a shock defeat at 88-7.
But Youles continued to apply himself to the task and with Adi Sreedharan moved the total to 108 when Youles was lbw to White for an excellent 30.
Scott Tite and Sreedharan began to accumulate, putting away the bad ball to great effect and took Sleaford to an exciting two-wicket win with Sreedharan on 22 and Tite 16.
Sleaford gained 20 points and are 22 points clear of Woodhall Spa in third, and trail second-placed Grantham by 16, with two games left.