Unison announced on 24 August that it would open its ballot on 12 September, closing it on 2 October.
The union's 45,000 members in the higher education sector, including registrars, cleaners, cooks, administration and security staff, make it second only to the University and College Union in size.
The sector's five unions - Unison, the UCU, Unite, the Educational Institute of Scotland and the GMB - entered a 7 per cent claim for 2012-13.
The claim was calculated on the basis of a 3.7 per cent inflation rate and 3.3 per cent to account for a "catch-up" after three consecutive years of low pay rises - 0.5 per cent, 0.4 per cent and 0.5 per cent.
The five unions have all rejected the final 1 per cent offer from the Universities and Colleges Employers Association. Four are preparing for strike ballots, with the GMB yet to announce its plans.
Unison's announcement of a ballot follows consultation with branches, which saw the offer rejected by a margin of two to one.
Jon Richards, Unison national secretary for education and children's services, said: "In real terms it represents a cut in pay, at a time when prices are rising and members are struggling."
He added that the employers "have refused to compromise, and it is clear that if we want to get more out of them, members need to vote for strike action".
A Ucea spokesman said the pay offer came alongside "a number of joint working proposals on other important elements of the unions' claim, including the response to a 'Living Wage' [demand] and offer for further work on equality issues".
The spokesman added that the overall staff benefit package "includes excellent conditions of service, defined benefits pensions and provision for incremental pay increases. Despite the economic difficulties and inflation issues that have impacted on all, HE pay and benefits packages continue to compare favourably to those outside of the sector. As always the employers remain open to discussions with the trade unions."